Post by Poultry in MotionIt was to be an example for all rec.aviation.rotorcraft readers to
follow. Fetters used "planeman" to steer public opinion.
Actually, I don't want any person to "steer" public opinion concerning
the Mini-500 helicopter. I only want the facts to steer public opinion,
and that is why we spent the time to compile all FAA accident reports
along with what we knew about the case, and put together one of the most
complete accident analyses reports even done on a kit-built aircraft.
Sure, it is subject to be ridiculed by those that refuse to believe the
facts. But I do not post this report for them, I post it for those with
an open mind that truly want to know the account. What the internet
assassins will have to say is of no importance, because if God himself
appeared to them and said it was all true, they would still refuse to
believe, and we all know that is true.
You can take all the parts of a JetRanger, put them in the hands of
someone that never built one, and that helicopter is only going to be as
good as it was assembled. It shames me to say that in large Americans
are the worse people I have ever sold a kit aircraft. Why? Right at half
the Mini-500's I sold went overseas. I have been overseas to see many of
them, and they were typically built and maintained beautifully. On the
other hand, the majority of the ones I've seen owned in the USA I would
consider junked. I can not count how many owners came to my factory for
the free pre-flight inspection we offered, always after 40 hours of
flying it, and all without tracking and balancing. Now they wanted us to
tell them why they are having problems, and in the mean time holding out
a handful of parts saying they didn't know where these went!
DO you know, that even with half of the Mini-500's being over seas, I
know of no one that was killed overseas, even though they fly them more?
All killed were in the USA. That also says a lot about the quality of
our US pilots compared to the overseas pilots. If you build it like junk
it will operate like junk, no matter how good the parts were. I have
only built 3 Mini-500's. They flew with almost no problems at all, but
they were assembled and maintained correctly by competent people and
pilots. The other 497 Mini-500's were built by other people, with the
exact same parts we built ours with, but with mixed results. Now, is
that the fault of the design and parts supplied? No.
Yes, there were some problems were I designed some parts wrong. It was,
in fact my first helicopter I ever designed. I learned, and I corrected
those flaws, all of them, for free or at my direct cost. All problems
were solved, if the owner elected to do the modifications. Most didn't
do them, and surprise!! They still had the problems.
Even with the few problems we had, it was still far less than any
certified helicopter has had, and all fixed at a fraction of the cost,
in fact totaling less than $5000. When was the last time you seen an
R-22 or R-44 AD for less than $5000? And how many have they had??
One important factor is to realize that 72% of the helicopter pilots
involved in Mini-500 accidents were either low-time helicopter pilots
with 50 hours or less, or did not hold a helicopter rating at the time
of the accident, and all were flying untested and untrimmed machines.
I am also proud to say that even with the problems we had, no one was
killed by a properly installed and maintained part that failed, or of a
poor flying characteristics.
Some say that the Mini-500 was designed with no testing. Actually it
probably has more testing than any other kit-built helicopter in the
world. We completed a 140 page structural analyses for the Mini-500, and
performed countless destructive testing, along with hundreds of hours of
flight testing. A fraction of this destructive testing can be seen at:
I will post the Mini-500 Accident report here again, for the new people
that never seen it. I know this has been the most action some of these
newsgroups have seen in years during their final death-throws, but I
will not be drug into a long internet battle, so those that want the
facts, just read the report. You already know who the blowhards are here
that will followup.
Mini-500 Accident Analysis
1995-1998
RHCI has always had a policy of not including the tail rotor gearbox
with the shipment of a Mini-500 helicopter to anyone who is not a
helicopter pilot. This policy has been strictly enforced throughout the
years in order to prevent customers who have not yet received proper
helicopter training from injuring themselves and the reputation of the
Mini-500. Unfortunately, it is impossible to enforce policies for those
few who will find a way around them. Several of the pilots involved in
a Mini-500 accident were not helicopter pilots at the time their
aircraft was shipped from the factory. They received the tail rotor
gear box because either they told RHCI they were buying the kit with
another person who was a helicopter pilot, or they were somehow able to
provide documents to RHCI showing that they were qualified to fly the
kit.
In this detailed analysis, it can be seen that all accidents are a
result of pilot error or a maintenance/assembly problem aggravated by
pilot error, and that the majority occurred to pilots with accumulated
low time in helicopters (100 hours or less).
Mini-500 Pilots’ Flight Experience
(Chart removed)
As shown in the chart above, 72% of the helicopter pilots involved in
Mini-500 accidents were either low-time helicopter pilots or did not
hold a helicopter rating at the time of the accident.
The Mini-500 has become the most popular helicopter in the world since
its introduction in 1990 and, like any other helicopter, has been
exposed to accidents. It was introduced at a time when the industry
needed an economical helicopter not only to purchase, but to operate and
maintain as well. New or low-time pilots were attracted to the Mini-500
as a way to enter the rotorcraft field or to build flight hours. The
relatively low acquisition cost allowed a new generation of pilots to
fulfill their dream of owning and flying a helicopter. High operating
costs had previously kept personal flying to a minimum. The Mini-500
created new pilots because it gave them a reason to become helicopter
certified, but this did not come without some problems.
The first few years proved to be the most difficult as the Mini-500 was
built and "field operated" by the pilots. As expected with any new
aircraft, a few mechanical problems occurred as the Mini-500 built up
flight hours. Components were re-engineered and retested before being
retrofitted to aircraft in the field. One by one these problems were
resolved.
The aircraft was introduced with the Rotax 582, a two-cylinder,
water-cooled engine, which is considered to be very reliable if properly
installed and maintained. The homebuilt industry finally had an
inexpensive helicopter that would make many people’s dreams of reliable
vertical flight come true. A "state-of-the-art" homebuilt helicopter had
achieved a record for affordability and reliability unmatched in the
homebuilt industry.
Conversations with Mini-500 pilots from other countries reveal that many
of them feel that the U.S. suffers from a severe lack of flying
discipline. There are fewer regulations in the U.S. than in most other
countries. The U.S. is still the world leader in the aviation industry,
and more regulations will not solve some of the problems. The only
solution now is "self-regulation.” Flight instructors must demonstrate
through their own actions that safety awareness must be applied to
flying helicopters. This may explain why the Mini-500 has fewer foreign
accidents than U.S. accidents.
A review of the Mini-500 NTSB accident briefs clearly demonstrates that
lack of proper training is the primary cause of accidents through
entering low rotor RPM conditions, followed by improper or inadequate
assembly and maintenance. These are by far the most preventable
accidents and require intensive training in avoidance and prevention
techniques as well as pilot judgment training. An analysis of the
Mini-500 accidents reveals that more pilot training is needed in
anticipating power changes, rotor RPM management, and keeping the dual
engine/rotor RPM tach in the VFR scan. The Power Enhancement Package
(PEP) introduced by RHCI improves the recovery of low rotor RPM, and
therefore, RHCI recommends that every Mini-500 owner install it in their
aircraft.
Most experienced flight instructors agree that low rotor RPM problems
are a result of rapid over pitching of the collective, causing an RPM
drop. This is similar to any powered helicopter rotor RPM droop, but the
throttle in the Mini-500 will respond immediately if the pilot properly
anticipates the need of increasing power before adding collective.
Pilots must obtain training in a similar helicopter without relying on
the correlator or governor before attempting to fly the Mini-500.
Mini-500 Accident Review
(NTSB Data and Unreported Accidents)
(Chart removed)
Pilot Error 24
Maintenance/Pilot Error 19
Undetermined/Pilot Error 1
TOTAL ACCIDENTS 44
Notes:
1. All information was obtained from the NTSB and/or directly from the
pilots, witnesses, friends, instructors, customers’ file, etc.
2. Most of these accidents were caused by several related factors and
probable causes may tend to be misleading (i.e. a roll-over may be
caused by excessive slope or unsuitable terrain, failure to successfully
autorotate, improper maintenance and assembly, collision with ground
object, etc.).
3. Mechanical failures are often caused by improper assembly,
maintenance procedures or exceeding limitations. All of them appear to
be attributed to this. In many cases, the pilot misinterpreted or
reacted improperly to a minor problem in flight.
4. Most of the accidents were attributed to pilots entering into a low
rotor RPM condition and not recovering properly.
5. Approximately 87% of accidents due to autorotative landings appear to
be caused by not recovering properly from low rotor RPM conditions. In
some cases the pilot reported an engine failure during power recovery on
a practice autorotation, or reported a rough engine followed by failure
when power was reduced for a landing. Post-accident engine run up found
wrong jets installed or in some cases no mechanical problems.
ALL OF THESE ACCIDENTS WERE AVOIDABLE!
Types of Accident
(Chart removed)
Types of Accidents Number of Accidents
A. Maintenance/Pilot Error 19
B. Low Rotor RPM 18
C. Collision With Ground Object 3
D. Fuel Exhaustion 2
E. Power Line Strike 1
F. Undetermined/Pilot Error 1
TOTAL 44
Accident Definitions
A. Maintenance/Pilot Error
Aircraft system failure caused by improper assembly, installation,
and/or maintenance procedures (i.e. wrong jets, belt alignment, improper
installation of components, loose parts, wrong adhesive, bad fuel, etc.)
followed by pilot error (i.e. not successfully autorotating or
recovering power after an emergency).
B. Low Rotor RPM
Inadequate control of aircraft, low rotor RPM due to practicing
autorotations, pilot operating behind the "power curve,” lack of
training, failure to maintain or recover from low rotor, etc.
C. Collision with Ground Objects
Collision during ground run-up or while in hovering flight (i.e.
aircraft tie downs, skids caught in a mound of protruding grass, etc.).
D. Fuel Exhaustion
Improper pre-flight preparation, fuel exhaustion due to running out of
fuel, leaking, or fuel restriction.
E. Power Line Strike
Collision with a power line while in cruise, takeoff, landing, etc.
F. Undetermined
The NTSB or RHCI has not determined a probable cause of the accident
(information unreliable, no eye-witnesses, information not obtainable to
determine cause).
RHCI has investigated every known Mini-500 accident, but the
investigations alone will accomplish nothing if recommendations aren’t
issued and adopted to prevent recurrence. Therefore, the following
Mini-500 accident analysis will take a detailed look at how some of the
accidents happened and how a typical safety awareness program can
prevent most of these accidents:
A. Maintenance - Of the 19 accidents in this category, approximately 98%
appear to have occurred as a result of engine failure due to having the
wrong jets installed, unauthorized modifications, improper assembly and
maintenance procedures. Most reported engine failures appear to have
resulted from improper installation and adjustments of the jets. If the
proper needle jet and needle position are not installed according to
RHCI’s instructions, Airworthiness Directives (AD’s) and advisories, the
engine will seize. This would most likely happen in a decent where the
improper needle jet arrangement tends to lean the mixture the most.
One accident was caused by installing a type of adhesive on the fuel
tank that was not the recommended one, causing the fuel filter to become
plugged. In several instances, the pilot or builder forgot to tighten a
part (i.e. a jam nut that secures the tail rotor push pull cable left
loose after trailering the aircraft; a loose hose clamp caused the
engine to lose coolant, and therefore overheat; the collective friction
was not tightened and the aircraft was left unattended causing it to
take off by itself; etc.). Lack of proper assembly procedures (i.e.
drive belt not properly aligned; improper installation of the collective
control tube; failure to remove packing material from inside the tail
boom after trailering; forgetting to change the center of gravity of the
aircraft after a much heavier pilot finished flying; etc.) has caused
several of the accidents. In one instance, RHCI suspected that the
builder reused the nuts and bolts located in the control system area,
because if he would have not done so, the certified bolts and nuts would
have not come loose.
When servicing and performing maintenance work in the Mini-500, it is
important to pay attention to detail and to make sure that no extra
parts are left inside any of the components. Compliance with RHCI’s
assembly manual, pilots operating handbook, service bulletins, AD’s,
safety notices and RHCI’s newsletters will help eliminate most, if not
all, maintenance problems on the Mini-500.
B. Low Rotor RPM - This has always been one of the most common types of
helicopter accidents and is quite often listed by the NTSB as a
contributing cause of a helicopter accident. It typically occurs to an
inexperienced pilot as a result of poor training or judgment and happens
to high-time pilots as a result of overconfidence in their ability.
Sometimes it occurs as a result of operating behind the power curve,
over pitching the collective, twisting the throttle the wrong direction
or exceeding the performance limits of the aircraft (i.e. operating at
high gross weight, attempting takeoff with high density altitude, etc.).
Mini-500 pilots must be made aware of the limits of the aircraft’s
correlator system.
If the pilot over pitches the collective without anticipating throttle,
a rapid decay will occur that can not be corrected without sufficient
airspeed or altitude. Usually the helicopter will settle rapidly to the
ground before the pilot can regain control of the RPM. This will occur
when landing with a tail wind, allowing rate of descent to build on
approach (especially below 100' AGL), landing at a high density altitude
site, operating at high gross weights, etc. It can generally be avoided
by using a high-speed shallow approach at higher density altitude
airports and aborting a takeoff if the aircraft will not hover
momentarily (at least a few inches above the surface). Student pilots
must be taught procedures for safe operation when flying at other than
standard atmospheric conditions.
Autorotations should be practiced frequently, with recovery made before
touchdown, until pilots’ skills are developed. New pilots, low time
pilots, and pilots not accustomed to flying light weight reciprocating
helicopters should not be allowed to practice autorotations in the
Mini-500 until they can do so proficiently in a similar two-place
helicopter with an instructor. These same pilots should also let
experienced pilots first fly their Mini-500, and make all trimming and
balancing adjustments. This will make the Mini-500 safer for a new
pilot to fly.
Of the 18 accidents in this category, most appear to have been caused
because the pilot put himself in a situation where he was not able to
recover from low rotor RPM (i.e. operating behind the power curve,
experiencing settling with power from 20 ft. or higher, etc.). The most
serious accidents have occurred as a result of practicing autorotations
when the pilot lacked thorough and recent training and experience in
helicopters. Intensive training in low rotor RPM recovery is necessary
in a similar type helicopter to reduce this type of accident.
C. Collision With Ground Objects - Three accidents have occurred in the
Mini-500 as a result of operating in close proximity to objects on the
ground. Most of these accidents occurred when hovering too close to the
ground. One pilot was practicing slide on landings from a hover, and
the skids caught on an aircraft tie down. On another occasion, a pilot
thought he could fly his aircraft out of his garage. While attempting
to do this, the down wash pulled the door down on top of the rotors.
Another pilot while hovering the helicopter for the first time, to break
in the engine, drifted off the tarmac area onto a grassy area, causing
one skid to get caught in a mound of grass.
RHCI has found that the odds of striking an object on the ground are
much greater than a hard landing due to engine failure, because of the
Mini-500’s high inertia system. An altitude of at least 12 inches will
avoid most objects on the ground.
Landing in unknown or unfavorable sites is generally a contributing
factor in this type of accident. Quite often the pilot has not seen the
object until it is too late, thereby colliding with it or losing control
trying to avoid it. Other times the pilot will land on a severe slope,
tall grass or soft terrain and the aircraft will roll-over. Ground
instruction on the types of terrain that are unsuitable for skid-type
landing gear must be given to students by flight instructors.
Instructors must use self-control when teaching new students.
Demonstrating landings in extremely hazardous areas has little training
value when teaching pilot judgment.
D. Fuel Exhaustion - There were two reports of accidents caused by fuel
exhaustion in the Mini-500. In one instance, the pilot failed to
pre-flight the aircraft for fuel level before taking off, causing it to
run out of fuel while in flight. On another occasion, RHCI suspected
that the pilot filled his gas tank with low octane level (less than 87
octane) without knowing it, causing the engine to fail due to
pre-detonation. It was reported to RHCI that the aircraft was freshly
refueled at the airport gas pump, and based on RHCI’s past experiences,
the grade usually offered by airports in auto gas is less than 87
octane. If the gas is in the ground for a long period of time, it will
lose octane, and low octane gas will pre-detonate in the Rotax engine,
as explained in the Rotax manual. RHCI recommends that pilots always
test the fuel for octane level when obtaining fuel from an airport or
even from the local gas station.
E. Power Line Strike - Even though there was only one accident caused
directly by a Mini-500 striking a power line, two other accidents can
also be attributed to power lines. One pilot flew into a power line at
70 MPH while flight testing for forward balance. The power line
contacted the aircraft on the mast, and the pilot was able to maintain
control up until ground contact. On another two occasions, the pilots
failed to see the power lines before taking off, but were able to miss
them. In the process, they allowed the rotor RPM to droop and were
unable to recover.
Contrary to popular belief, most wire strikes occur in clear weather
conditions. This type of wire encounter is most likely to be fatal since
the aircraft is usually operating at a high rate of speed at the moment
of impact. Intensive ground training on wire strike avoidance is
required to avoid this common fatal accident. Only experienced pilots
should fly low level operations.
G. Undetermined/Pilot Error - Only 1 accident in the Mini-500 has been
undetermined during this period. The pilot did not successfully
complete an autorotation and did not have the engine disassembled to
determine the reason for failure. Therefore, engine failure is
undetermined.
The Revolution Mini-500 makes up approximately 4% of the total U.S.
civil helicopter fleet (year end 1998). There are approximately 436
Mini-500 helicopters in the U.S. compared to 10,892 other types of
helicopters. Of the 436 Mini-500’s in the U.S. fleet, 38 were involved
in accidents for the calendar years 1995-1998, or approximately .35% of
the U.S. fleet. Of the 10,892 other helicopters, 716 were involved in
accidents during this same period, or approximately 6.5% of the U.S.
fleet. This includes helicopters used for such diverse operations as
crop dusting, corporate, off-shore, personal and business, EMS, etc.
Considering the role the Mini-500 has in the worldwide personal use
market, the Mini-500 would be expected to have a proportionately higher
number of accidents each year. Enstrom had similar problems back in the
1970's when F. Lee Bailey spiffed up the F28A and targeted the
businessman market. The accident rate soared as dealers sold executives
the idea of the modern “flying carpet.” Unfortunately, despite claims
made as early as 1950, the world is still not ready for a helicopter in
everyone's garage. Even the MD-500, one of the easiest light helicopters
to fly, can be a handful to an inexperienced pilot, a phenomenon that is
not unlike the V-Tail Beech or the Cessna Citation. Considering the fact
that Mini-500 helicopters are used for some type of personal recreation
(which generally involves numerous takeoffs/landings), the accident rate
per aircraft flying becomes even more favorable.
To take this analysis a little further, let's look at the total
transportation accidents records in the U.S. as published annually by
the NTSB:
Comparison of U.S. Transportation Fatalities for 1997
Fatalities Fatalities
Passenger Cars 22,227 Pedacycles 800
Trains 746 Airplanes (G.A.) 646
Buses 15 Helicopters 78
Motorcycles 2,099 (Mini-500) 3
During 1998, total helicopter fatalities were 91, while the Mini-500
only had 4.
A detailed analysis would be necessary in order to assess risk/benefit
in any form of transportation. How often has it been said in the
helicopter industry (since Igor Sikorsky first said it) that a
helicopter is potentially one of the safest forms of transportation?
This statement may very well prove to be true someday.
Mini-500 Total Accidents
(Chart removed)
Out of 44 flight related Mini-500 accidents, there were 35 accidents
with minor or no injuries (80%), 2 serious injuries (4%), and 7 fatal
(16%). Of the nine serious and fatal accidents, five were caused by
pilot error and four by maintenance aggravated by pilot error.
Mini-500 Accident Rate vs. Total Aircraft Flying
(Chart removed)
RHCI estimates that about 400 out of 521 Mini-500 sold are flying or
capable of flight. RHCI bases this estimate on conversations and
letters received from the builders. This indicates that 44 (11%) out of
an estimated 400 flyable Mini-500s were involved in an accident.
Conclusion
The results of accident investigations or safety studies are useless
unless the information is readily available to those who need it.
Pilots are still cited as a cause or contributing factor in about 85% of
all general aviation accidents. While new technology and design have
clearly played an important role in the improved safety record, the
potential for continued improvements down the road may be diminishing
and we need to focus on the human factors affecting the safety of flight
operations: factors such as situational awareness, error chain detection
and analysis, communication skills, decision-making, stress management,
etc.
This Mini-500 Accident Analysis has been compiled in the interest of
helicopter safety and can be adapted to any type of helicopter safety
program. Flight schools and instructors are urged to review these and
other Mini-500 accident data with students to make them aware of some
common mistakes made by Mini-500 pilots. All helicopter pilots are aware
of the inherent risks involved in aviation, especially the unique risk
to helicopter operations. Any type of flying activity involves certain
risk, whether it be in an ultralight airplane or a commercial airliner,
and pilots have accepted the risk realizing full well the consequences
when something goes wrong.
Despite repeated criticism from opponents, the Mini-500 helicopter has
proven itself to be one of the safest helicopters ever manufactured. It
was certified as a homebuilt kit under the 51% category. Its primary
markets (personal training for adding on hours and personal use) have
placed it in a high risk category and not unlike the Cessna 152, it is
exposed to a higher accidents rate.
The Mini-500 and the pilots that fly it throughout the world have
achieved a remarkable record in helicopter safety. It has given many the
opportunity to finally own a helicopter, and it has helped many pilots
to increase their helicopter flight time inexpensively. It has opened
the market and allowed pilots all over the world to learn to fly
helicopters affordably. A Mini-500 as well as any other helicopter will
crash as a result of low rotor RPM or poor maintenance. These types of
accidents may very likely occur in a helicopter other than the Mini-500,
but that would probably not receive the same level of attention as a
Mini-500 accident.
Many pilots who have been flying the Mini-500 are aware of some of the
more controversial accidents in the past few years. Many of us in the
industry are aware of these accidents, but it is rare that the actual
circumstances are revealed. NTSB data tends to indicate the probability
that the accident was caused by pilot error. RHCI has acted responsibly,
as it always has in the past, to prevent future accidents. I am
comfortable knowing that with good training and supervision, people are
probably safer in the aircraft than in the car.
NOTES: All data and statistics have been obtained from NTSB and the
Helicopter Association International (HAI) sources.
Mini-500 Reported Accidents to the NTSB
The following accident summaries are abstracts from NTSB Accident
Reports and are intended to keep operators, maintenance personnel and
safety managers aware of the Mini-500 helicopter safety trends. Except
for RHCI Investigative Findings, the text of these reports is taken from
NTSB reports; no editorializing has been done.
Followng each NTSB accident report, RHCI includes its findings (RHCI
Investigative Findings) after investigating each accident and obtaining
information from the NTSB, FAA, pilots, witnesses, and RHCI’s customers’
file. It is RHCI’s intent to clarify the information and help those
seeking the real cause of the accidents to understand what could go
wrong when flying not only the Mini-500, but any helicopter. The RHCI
information is the opinion of RHCI, and should not necessarily reflect
the opinion of the NTSB, FAA or any other affiliated group or
organization.
(1) NTSB Identification: CHI95FA242
Accident occurred Jul-27-95 At Oshkosh, WI
Aircraft: Revolution Helicopter Mini-500, registration: N500ZZ
Injuries: 1 Uninjured
The amateur-built helicopter was conducting a demonstration flight
during the annual EAA convention. During the first flight after
re-jetting of the carburetor, the helicopter experienced a total loss of
engine power. During the autorotation into a crop field, the helicopter
was substantially damaged when the skid shoes caught in the terrain,
failing the left skid and fracturing the shoe on that skid. Subsequent
examination of the engine revealed that the rear piston had seized in
the cylinder. The owner of the company which produces the helicopter
stated that the re-jetting of the carburetor was made in an attempt to
achieve what were thought to be correct readings in main rotor RPM and
EGT after replacement of both gauges. The company owner attributed the
piston seizure to the re-jetting. The skid shoes were new and had been
tested only on concrete. The owner said that the design contributed to
the damage to the helicopter. Probable Cause the inadequate design of
the helicopter skid shoes. Factors related to the accident were: false
indications of rotor RPM and EGT which led to seizure of the piston.
Full Narrative
On July 27, 1995, at 0930 central daylight time, an amateur built
Revolution Helicopter Mini-500, N500ZZ, registered to Revolution
Helicopter Corp. of Excelsior Springs, Missouri, and piloted by a
commercial helicopter pilot, experienced a total loss of engine power
while in cruise flight. During an auto rotational (forced) landing,
one-half mile west of Wittman Regional Airport, Oshkosh, Wisconsin, the
helicopter sustained substantial damage. The pilot reported no injuries.
The local 14 CFR Part 91 flight was operating in visual meteorological
conditions. No flight plan was on file. The flight departed at 0920. The
accident occurred during the annual Experimental Aircraft Association's
convention. The helicopter was conducting a demonstration flight in the
vicinity of the airport at Oshkosh, Wisconsin.
Personal Information
The pilot had obtained approximately 100 hours flight time in this type
of helicopter, at the time of the accident. This was the first flight of
the day.
Aircraft Information
The helicopter had accumulated 210 hours time in service at the time of
the accident with less than one hour since inspection and maintenance to
the carburetor which included changing the jetting.
Wreckage And Impact Information
The helicopter impacted the terrain during a forced landing in an open
field approximately one-half mile west of Wittman Regional Airport,
Oshkosh, Wisconsin. There were two ground scars consistent with the size
and shape of the skids running westerly from the first visible impact
mark to the wreckage. The left skid was broken away from its mounting.
The tail boom was lying to the north of the main wreckage and exhibited
sharp fractures at the broken end. The tail rotor blades were bent. The
main rotor blades were bent and broken and one had red paint on it
similar to the color of the tail boom. Subsequent examination of the
engine found that the rear piston was seized in the cylinder. The owner
of the company producing the helicopter said that two changes to the
helicopter just prior to the flight were of concern. He stated that a
new rotor/engine RPM instrument was installed at the same time as a new
exhaust gas temperature (EGT) gauge. He said that prior to the
installation of these gauges that the helicopter was operating without
incident; however after reading the indications on these new instruments
re-jetting of the carburetor was done in an attempt to bring the
readings within gauge limits. The owner attributed the seizure to the
previous accomplished re-jetting. He said that at the same time a new
set of skid shoes were installed on the skids of the helicopter and
testing was done on concrete only. When an autorotational landing was
conducted in a crop field the new skid shoes dug in and stopped the
helicopter in a short distance, failing the left skid and fracturing the
skid shoe on that skid.
Additional Data/Information
The NTSB did not exercise its right to retain custody of the wreckage.
When the on scene investigation was complete the wreckage was removed
and retained by the owner. Party to the investigation was the Federal
Aviation Administration, Flight Standards District Office, Milwaukee,
Wisconsin.
RHCI INVESTIGATIVE FINDINGS
As published in the September 1995 “Reaching the Customer” newsletter,
the following report was written by Brian Thomas (RHCI’s Test Pilot):
Many of you have been asking questions about the autorotation
capabilities and crashworthiness of the Mini-500. Well, I will answer
some of those questions, but this time with an actual experience...
Oshkosh was less than a week away, the composite department was still in
the learning stage and needed much supervision, and the assembly manual
was a priority. Our minds were divided onto these other projects while
we were working on preparing the aircraft for the show. As a result of
this, we made three mistakes which caused this whole incident.
First, we installed a new rotor/engine tachometer in the aircraft just
before the fly-in. We thought the gauge was calibrated correctly.
Also, we were using a new EGT gauge that was supposed to be
self-compensating for temperature. The week before Oshkosh, the
temperature at the factory was 95 to 100 degrees F. with 95% humidity.
After making these changes, the aircraft experienced a loss in
performance. Our EGT temperatures were only running about 900 to 1000
degrees F. We attributed this loss of performance to the high
temperature and humidity. Using the EGT gauge as a guide, we leaned the
mixture by installing much smaller main jets and lowering the needles.
This brought the temperature up to 1100 and 1200 degrees F., but with no
significant increase in performance. Through testing, we then learned
that the rotor/engine tachometer was calibrated too low. After
re-calibration, our performance returned. EGT’s were still reading
normally and were left as changed. I immediately conducted a short test
flight and everything seemed to be working well.
Second, we installed wear shoes on the bottom of the skids to prevent
excessive wear on concrete and rocky surfaces. Our intentions were to
make this an option later. These shoes consisted of eight pieces of
steel, four per skid, approximately five inches long, riveted with six
rivets each, evenly spaced along the skids.
Third, we did not test the skid shoes on grass or dirt to see if they
would change the run-on landing performance.
Now for what happened at Oshkosh. It was the first flight on the first
day of the show. I started the aircraft and hovered around the grass
runway for a few minutes and the aircraft was operating normally. I
then departed and entered the traffic pattern. On my first trip around
the pattern, the aircraft was performing perfectly. I was keeping an
eye on the EGT gauge to make sure that the temperatures were still good,
since it was cooler at Oshkosh than at the factory. The temperature was
still 1100 and 1200 degrees F. On my second trip around the pattern,
the engine suddenly stopped. The EGT gauge that we installed was not as
accurate as we thought and the engine hot seized. At the time the
engine quit, I was at 300 feet AGL with an airspeed of 70 MPH. I
entered autorotation and steered for a nearby clover field. The
autorotation was uneventful, as was the flair and touchdown.
As I have previously said, the Mini-500 is one of the best autorotating
helicopters I have ever flown. The problems began during the ground
slide. Immediately upon touchdown, the skid shoes caught in the clover
and soft dirt so hard that one shoe was pulled off the skid! The left
skid caught and jerked so hard that the legs buckled. The legs did not
buckle because they are not strong enough. They buckled from the
enormous force of trying to stop 730 lbs. of aircraft so quickly. The
skid shoes were the cause, not the legs. When the left skid buckled,
the aircraft started to go onto its left side. As a result, one rotor
blade contacted the tail boom. Part of the reason that the skid shoes
caught so hard is that the normal procedure for the Mini-500 is to lower
the collective all the way down after touchdown from an auto. On most
helicopters with skid shoes, the procedure is to hold the collective up
until the helicopter comes to a stop to prevent the shoes from digging
in too badly. I am very familiar with this procedure, but failed to
relate it to the Mini-500.
(2) NTSB Identification: LAX96LA150
Accident occurred Mar-31-96 at San Carlos, CA
Aircraft: Lampert Revolution M500, registration: N750GL
Injuries: 1 Minor
According to FAA airman records, the pilot did not hold a rotorcraft
category rating. FAA inspectors examined the pilot's logbook and
reported that he received a solo endorsement in helicopters about 1 1/2
years ago. The pilot was returning to the airport following a local area
flight. About 1 mile west of the airport, the pilot began to smell
something burning and said he sensed something was wrong. Shortly
thereafter, he heard a "slap" sound as the helicopter transitioned
through 50 feet and 50 knots about 1/4 mile from the runway. The pilot
stated that he "didn't do anything [with the controls] but keep it
headed for an open area between the taxi way and the runway." The pilot
said he did not flare or touch the collective, and the helicopter hit
hard in the open area and rolled on its left side. An FAA airworthiness
inspector examined the helicopter and found the engine to transmission
drive belt fragmented, with rubber transfer throughout the engine
compartment. Rubber transfer on the pulleys showed a forward movement
pattern of the belt off the pulley. The inspector reported that the
pulley was designed without a flange or other means to keep the belt
aligned.
Probable Cause
The pilot's failure to recognize a drive train disengagement and
initiate an autorotation. The inadequate engine-to-transmission drive
belt/pulley design, and the pilot's limited training and experience in
rotorcraft operations were factors in this accident.
Full Narrative
On March 31, 1996, at 1347 hours Pacific standard time, a homebuilt
experimental Lampert Revolution M500 helicopter, N750GL, collided with
the ground and rolled over during landing at San Carlos, California. The
aircraft was owned, built, and operated by the pilot. Visual
meteorological conditions prevailed at the time and no flight plan was
filed. The helicopter sustained substantial damage. The non-rotorcraft
rated private pilot, the sole occupant, sustained minor injuries. The
flight originated at Half Moon Bay, California, on the day of the
accident at 1315 as a personal cross-country flight to San Carlos.
According to FAA airman records, the pilot does not hold a rotorcraft
category rating. FAA inspectors examined the pilot's logbook and
reported that he received a solo endorsement in helicopters about 1 1/2
years ago. The pilot reported that he flew from San Carlos to Half Moon
Bay earlier in the day and was returning to the San Carlos airport.
About 1 mile west of the airport the pilot began to smell something
burning and said he "sensed something was wrong." Shortly thereafter, he
heard a "slap" sound as the helicopter transitioned through 50 feet and
50 knots about 1/4 mile from the runway. The pilot stated that he
"didn't do anything [with the controls] but keep it headed for an open
area between the taxi way and the runway." The pilot said he did not
flare or touch the collective and the helicopter hit hard in the open
area and rolled on its left side. An FAA airworthiness inspector
examined the helicopter and found the engine to transmission drive belt
fragmented, with rubber transfer throughout the engine compartment.
Rubber transfer on the pulleys showed a forward movement pattern of the
belt off the pulley. The inspector reported that the pulley is designed
without a flange or other means to keep the belt aligned.
RHCI INVESTIGATIVE FINDINGS
RHCI was allowed to investigate the damaged aircraft with the FAA
present in an attempt to discover why the belt failure occurred. It was
explained to the FAA investigator how the belt alignment worked, and the
flanges on the sprocket were pointed out to him at that time. They were
in place and functioning. There was another Mini-500 in the same hanger
built by the same person, but not yet flown. RHCI showed the FAA
inspector that the belt on the crashed Mini-500 had not been properly
aligned, and that the same mistake was made on the other Mini-500 he
built as well. It is unknown why the inspector said the sprocket was
designed without a flange or other means to keep the belt aligned, even
when RHCI showed him the flanges and explained their operation, but RHCI
had no influence on the outcome of an NTSB or FAA investigation. With
hundreds of Mini-500 now flying, the belt alignment system has obviously
proved itself if properly installed and maintained.
(3) NTSB Identification: LAX97LA150
Accident occurred Apr-16-97 at Lihue, Kauai, HI
Aircraft: Duff Mini-500, registration: N13118
Injuries: 1 Fatal
A witness stated that the helicopter appeared to be about 500 feet AGL
and that he could hear a "tick-tick-tick" sound as the aircraft started
yawing to the left and right. The yawing motion was followed by a left
roll to an inverted attitude from which the aircraft descended nose down
to the ground and crashed. At the time that the roll began, the tail
rotor and gearbox were observed to separate from the tail boom.
Examination of the helicopter did not disclose any pre-accident engine,
fuel system, or flight control system malfunctions or abnormalities.
Black paint, the color of the tail boom, was evident on the leading edge
of both main rotor blades, and four impact dents were found on the tail
boom. Paint transfer indicated that the upper right-hand windshield had
also been impacted by the main rotor blades. Review of the student
pilot's flight records disclosed that he had obtained 12 hours of
helicopter dual instruction in 1991, with only 1 hour listed for
autorotations. No record of additional dual instruction was found
between 1991 and the date of the accident.
Probable Cause
the student pilot's improper use of the helicopter flight controls,
which resulted in rotor contact with the tail boom and loss of control.
Factors relating to the accident were: the pilot's lack of total and
recent training and experience in airborne control of helicopters.
Full Narrative
On April 16, 1997, at 1424 hours Hawaiian standard time, a single-place
Duff Mini-500 homebuilt experimental helicopter, N13118, was destroyed
when it impacted the ground in the vicinity of Lihue, Kauai, Hawaii. The
student pilot was fatally injured. The flight departed from the pilot's
Anahole residence for an unknown destination. No flight plan was filed
for the personal flight and no en route communications were received by
any Federal Aviation Administration (FAA) facility. An eyewitness, who
was approximately 1/4 mile from the crash location, stated that the
aircraft appeared to be about 500 feet AGL, and that the engine did not
sound as if it was maintaining a steady RPM. The aircraft was then
observed to start yawing to the left and right, which was followed by a
left roll to an inverted attitude, from which it descended nose down to
the ground. At the time the final roll began, the tail rotor and gear
box were observed to separate from the tail boom. The witness also
stated that he heard a "tick-tick-tick" sound emanating from the
aircraft at the time that it appeared to be in trouble. The helicopter
was examined by an FAA airworthiness inspector from the Honolulu,
Hawaii, Flight Standards District Office, with the technical assistance
of the aircraft kit manufacturer's safety investigator. According to
their report, which is appended to this report, the fuel system was
intact and without obstructions. The system was equipped with a
motorcycle fuel filter, but no debris or obstructions were found in the
filter and there was no evidence of a fuel problem. All control system
linkage breaks that were found appeared to have resulted from fracture
and not fatigue, and all rod ends that were broken had first been bent.
The engine exhaust manifold bolts and head bolts were found to be finger
tight. The internal parts of the engine were in new condition and
correctly assembled. One manufacturer's bulletin on the carburetor,
which specified a change in jets, had not been complied with; however,
the inspector stated that the engine had been running rich so the
noncompliance was not considered significant. The electronic engine
ignition system was intact and functional. The engine contained coolant
and oil, and no evidence was found that would indicate an engine
problem. The main transmission and tail rotor gear box contained
lubricant. The tail rotor gear box was severed in half but the internal
gears were in new condition. The tail rotor blades were bent and one
main rotor blade had separated from the rotor head and was found 30 feet
away from the aircraft. Black paint, the color of the tail boom, was
evident on the leading edge of both main rotor blades, and four impact
dents were found on the tail boom moving progressively towards the
cockpit. The upper right-hand windshield was separated from the airframe
with a smear of paint transfer identical to the main rotor blade color.
The FAA inspector stated that the student pilot's records indicated
that he had received 12 hours of helicopter flight instruction in 1991,
of which a total of only 1 hour was logged for both autorotation and
pattern flight. Five years later, and without any known additional
instruction, the pilot obtained and assembled a Mini-500 helicopter and
proceeded to train himself to fly it after a flight instructor
endorsement for solo flights that the FAA stated was in violation of
FAR's 61.59, 61.87, 61.189, and 61.195.
RHCI INVESTIGATIVE FINDINGS
The FAA asked RHCI to join the Investigation Team in an attempt to
establish a cause for the accident. RHCI compiled information through
the local police department, eye witnesses, friends of Mr. Duff, and the
NTSB and FAA.
After RHCI’s examination, it is RHCI’s opinion that no mechanical
failures occurred during the aircraft's last flight, and if it were not
for the crash, the aircraft could be flying today. By compiling the
evidence, RHCI believes that the best scenario which led to the crash is
as follows:
Mr. Duff had received 12 hours of helicopter flight instruction back in
1991. Only one hour during this time was logged for both autorotations
and pattern flight. Five years later, and without any further
instruction, Mr. Duff assembled a Mini-500 helicopter kit and proceeded
to train himself to fly it. During his third flight, and his longest
cross country, Mr. Duff probably allowed his rotor blades to lose RPM to
the point that the low rotor warning light and the low rotor warning
horn alerted him of this situation. Without the proper experience and
training, Mr. Duff overreacted and overspun the rotor system in an
attempt to normalize his RPM. The aircraft yawed to the right, and then
again yawed to the left as he chopped power to avoid the overspin. While
the aircraft was yawing, he would have been trying to regain control of
the cyclic, collective and anti-torque pedal systems. His responsibility
was then overloaded and he failed to catch up with the controls and
decayed his rotor RPM to the point that the centrifugal force of the
blades was not great enough to hold them in their plane. The oncoming
forces of airflow and retreating blade stall caused the aircraft to roll
left and then invert. What RPM was left in the rotors then allowed them
to contact the tail boom, striking it with such force that it broke the
tail rotor gear box off of the tail boom. The rotors also folded and
contacted the cockpit. The pilot lost control, and then lost RPM and
failed to recover. The aircraft then impacted the ground at a speed
well in excess of 100 MPH. The pilot instantly died from impact. The
cause of the crash was pilot error, due to his inability to fly a
helicopter.
(4) NTSB Identification: CHI97LA222
Accident occurred Jul-19-97 at Ava, MO
Aircraft: Morgan Mini-500, registration: N500XM
Injuries: 1 Uninjured
On July 19, 1997, at 1315 central daylight time, an experimental Mini
500 helicopter, N500XM, was substantially damaged during a forced
landing near Ava, Missouri. The pilot reported that the engine lost
power during cruise. He was not injured. The 14 CFR Part 91 flight had
departed Cabool, Missouri, about 1245 with a planned destination of Ava,
Missouri. Visual meteorological conditions prevailed and no flight plan
was filed.
RHCI INVESTIGATIVE FINDINGS
The NTSB had this Mini-500 delivered to RHCI to help in the
investigation. With the NTSB present, it was discovered that the
original airplane jetting was still installed in the carburetors. The
engine failed due to high EGTs from failure to follow instructions and
re-jet the engine upon installation for helicopter use. The helicopter
landed on the side of a 30 degree hill, and rolled over.
(5) NTSB Identification: LAX97LA269
Accident occurred Jul-31-97 at Agua Dulce, CA
Aircraft: Mitteer Mini-500, registration: N501GM
Injuries: 1 Serious
The pilot of the recently completed, kit-built helicopter, stated that
the engine stopped abruptly about 150 feet above helipad elevation as he
was on base leg for landing. A hard landing resulted from an
unsuccessful autorotation. Examination of the helicopter revealed that
the size of the metering jet installed in both carburetors by the
owner/pilot was too small, and that the fuel metering pin in both
carburetors was improperly set so as to create an excessively lean
fuel/air mixture, which resulted in loss of engine power. The pilot
reported having 50 hours total helicopter flight time and that he last
practiced autorotations 22 years prior to the accident. A revised
aircraft assembly manual, which added a discussion of fuel jets and
metering pins, was offered to holders of the earlier manual at a reduced
price; however, the owner/builder did not purchase it. An article in the
manufacture's newsletter, again discussing the importance of this
subject, was sent to the owner/builder's address of record.
Probable Cause
Failure of the owner/builder to obtain and comply with service
literature from the kit manufacturer, which resulted in improper setting
of the carburetor fuel mixture and led to loss of engine power. An
additional cause was the pilot's failure to successfully autorotate the
helicopter to an emergency landing. The pilot's lack of total experience
in the type helicopter and lack of recent experience in performing
autorotations were related factors.
Full narrative
On July 31, 1997, at 1945 hours Pacific daylight time, an experimental
(amateur built) Mitteer Mini 500 helicopter, N501GM, was substantially
damaged when it collided with terrain while on landing approach to a
private helipad at Agua Dulce, California. The commercial pilot was
seriously injured. Visual meteorological conditions prevailed for the
personal flight. The recently completed helicopter departed from the
helipad about 1940. According to the pilot's brother, the pilot related
from his hospital bed that the engine stopped abruptly about 150 feet
above helipad level as he was on base leg for landing. Because previous
approaches had been at too steep an angle, the pilot was deliberately
flying a flatter and slower approach, which, together with his low
altitude when the engine failed and lack of a suitable landing site,
made his autorotation unsuccessful. According to inspectors from the
Van Nuys Flight Standards District Office, the aircraft impacted on a
two-lane asphalt road about 1/8 mile from the helipad in a valley about
100 feet below the helipad elevation. Terrain slopes upward about 45
degrees on one side of the road and there are power transmission lines
on the other side of the road, however, the helicopter contacted neither
prior to impacting on the roadway. The impact bent both landing skids
outward and the belly of the fuselage contacted the pavement. The
pilot's seat structure exhibited compression failure with more collapse
on the left side than the right side. The two rotor blades had minor
damage on the lower surface of the tips. After impact, the aircraft
rotated 90 degrees to the right and came to rest about 10 feet away from
the impact mark, resting on its left side. According to the inspector,
no airworthiness certificate or operating limitations had been issued to
the builder/pilot by the Federal Aviation Administration. The recording
hour meter in the aircraft indicated 8.4 total hours, however, the pilot
told his brother that he had operated the aircraft more than those
hours. The pilot's logbook indicated total operating time since new,
including ground run time, of 14.8 hours. The first entry was about a
month before the accident. The last entry in the logbook, for the
previous flight, indicates that the pilot changed the fuel metering jets
in the carburetors to "150" size. The pilot reported having 50 hours
total helicopter flight time, with 18 hours in the previous 60 days. In
a telephone conversation with the Safety Board in December, 1997, the
pilot said that he received his helicopter training in 1975 in a Bell 47
helicopter, and that was the last time he practiced an autorotation to
landing. In June, 1997, prior to first flying his Mini 500, he took 2
hours of dual instruction in a Robinson R-22, but did not perform any
autorotation practice. Representatives of the company which manufactures
the parts kit for the helicopter, examined the aircraft and determined
that the size of the metering jet installed in both carburetors by the
owner/pilot was too small, and that the fuel metering pin in both
carburetors was improperly set so as to create an excessively lean
fuel/air mixture in the engine. Examination of the aft piston of the two
cylinder engine through the exhaust port showed scoring on the sides of
the piston and evidence of "hot seizure." A manufacture's bulletin on
the subject of sizing metering jets and metering pins in the carburetor
to control exhaust gas temperature was issued on May 7, 1996, the same
day the kit was shipped to the manufacture's dealer. The dealer signed
and returned a receipt for the bulletin to the manufacturer who placed
it in the file for the aircraft serial number. The kit was sold to the
builder/pilot on January 13, 1997, and there is no record whether there
was a copy of the service bulletin with the kit. An article in the
manufacture's newsletter of March, 1997, discussed the importance of
this subject again. According to the kit manufacturer, the newsletter
was mailed to the builder/pilot's address of record, which was his
business address. A revised aircraft assembly manual which added a
discussion of fuel jets and metering pins was offered to holders of the
earlier manual at a reduced price. The owner/builder did not purchase
the revised manual.
RHCI INVESTIGATIVE FINDINGS
The NTSB invited RHCI to help in the investigation. With the NTSB
present, it was discovered that the jetting was incorrectly installed in
the carburetors to the maximum lean settings, and the EGT gauge was
labeled by the pilot at a red line of 1300F. The EGT should never run
more than 1150F. The engine seized due to high EGTs from improper
jetting. The accident was caused from failure to perform successful
autorotation. In fact, the rotor blades were nearly undamaged and not
turning at the time of impact. It is believed the helicopter fell more
than 50 feet, and hit on a hard paved road.
(6) NTSB Identification: IAD97LA113
Accident occurred Aug-23-97 at New Philadelphia, OH
Aircraft: Haines Revolution Mini-500, registration: N7240E
Injuries: 1 Uninjured
On August 23, 1997, at 1045 eastern daylight time, a Haines Revolution
Mini 500, homebuilt helicopter, N7240E, was substantially damaged when
it collided with the ground during takeoff at Harry Clever Field, New
Philadelphia, Ohio. The certificated private pilot was not injured.
Visual meteorological conditions prevailed for the local, personal
flight that originated at New Philadelphia, Ohio. The flight was
conducted under 14 CFR Part 91 and a visual flight rules flight plan was
not filed. According to a Federal Aviation Administration (FAA) Safety
Inspector, the pilot was taking off, and about 50 feet above the ground,
the rotor RPM started to decay. The pilot said he applied more power,
but the engine sputtered, and shortly thereafter the engine lost power.
The pilot said he entered autorotation, but he did not have enough rotor
speed to land safely, and the helicopter struck the ground. According to
the pilot, he had flown the helicopter for an hour the day before, and
he had refueled the helicopter the day of the accident. The fuel tank,
fuel lines, fuel filter and fuel pump were examined after the accident
by the FAA Inspector. According to the Inspector, the examination did
not disclose any contaminants. The helicopter was moved to a hangar for
further examination.
RHCI INVESTIGATIVE FINDINGS
It was reported to RHCI that the pistons had holes burnt through them,
and the tongues were gone from the spark plugs. This can happen only
with the use of low octane fuel or if the cylinder head of the engine
has been modified to increase compression ratio. It was reported to
RHCI that the aircraft was freshly refueled at the airport gas pump. The
cause of engine failure was due to pre-detonation of fuel. It is
suspected by RHCI that the gas used prior to the flight was less than 87
octane, which is usually the grade offered by airports in auto gas. If
the gas is in the ground for a long period of time, it will lose octane,
and low octane gas will pre-detonate in the Rotax engine, as explained
in the Rotax manual. The cause of the accident was failure to perform a
successful autorotation.
(7) NTSB Identification: FTW97LA328
Accident occurred AUG-26-97 at Huffman, TX
Aircraft: Fingerhut Revolution Mini-500, registration: N570F
Injuries: 1 Uninjured
The student pilot experienced a disconnect of the collective control
system which resulted in the main rotor blades going to flat pitch while
in cruise flight at 800 feet MSL. When the pilot attempted to cushion
the landing by increasing collective pitch, the helicopter yawed to the
left prior to touching down and the helicopter rolled over on its side.
Examination of the wreckage revealed a disconnect of the collective
flight control system between the collective riser block (P/N 0153), and
the rod end (P/N 0600) for the collective control tube. Examination of
the threaded areas of the collective riser block and the rod end
revealed that the threads on the aluminum collective riser block were
found to be displaced or pulled out due to inadequate improper
penetration. The information supplied by the kit manufacturer was
insufficient to properly rig the flight control system.
Probable Cause
The disengagement of the helicopter's collective control tube due to
improper installation by the builder. Factors were the lack of
sufficient information provided by the kit manufacturer and the pilot's
inability to cushion the landing.
Full Narrative
On August 26, 1997, at 2000 central daylight time, a Fingerhut
Revolution Mini 500 homebuilt helicopter, N570F, was substantially
damaged during a forced landing near Huffman, Texas. The student pilot,
sole occupant of the helicopter, was not injured. The helicopter was
owned and operated by the pilot under Title 14 CFR Part 91. Visual
meteorological conditions prevailed for the local flight for which a
flight plan was not filed. The instructional flight originated from a
helipad at the pilot's home in Huffman, Texas at 1945. According to the
pilot, he experienced a disconnect of the collective control system
which resulted in the main rotor blades going to flat pitch while in
cruise flight at 800 feet MSL. The pilot added that he elected to
execute a running landing to a cultivated field rather that try to land
in a confined helipad. During the landing flare the helicopter yawed to
the left as the pilot applied collective to cushion the landing prior to
touching down. The pilot added that the helicopter was not properly
aligned during touch down and the helicopter rolled over on its side.
The FAA inspector confirmed that the 1997 model helicopter sustained
structural damage. He added that the student pilot was properly endorsed
for solo flight and had accumulated a total of 50 hours of flight in
helicopters, of which 28 were in the same make and model. According to
the aircraft maintenance records, the helicopter had accumulated a total
of 28 hours since it was assembled by the pilot from a kit. Flight
control continuity was confirmed by the FAA inspector to the cyclic and
anti-torque systems of the helicopter. Examination of the helicopter by
the FAA inspector revealed that a disconnect of the collective flight
control system between the collective riser block (P/N 0153), and the
rod end (P/N 0600) for the collective control rod (P/N 0002) With the
aid of 10 power magnification, the inspector examined the threaded areas
of the collective riser block and the rod end. The threads on the
aluminum collective riser block were found to be displaced or pulled
out. See enclosed drawing showing the 0.314 inch penetration on the
threaded surface of the riser block and the first 0.388 inch engagement
on the rod end. The FAA inspector also noted that the control rods
provided by the helicopter manufacturer were not provided with a
"witness hole" so either the installer or an inspector could verify the
amount of rod end penetration into the threaded control tube.
Furthermore, the assembly instructions provided by the manufacturer did
not stipulate the minimum amount of thread engagement required in any of
the rod ends in any of the flight control tubes in the helicopter, nor
did it warn the potential builder of the criticality of proper thread
engagement and security. To assist with the investigation, the FAA
inspector inspected a like helicopter to establish a comparison on the
installation of the flight control systems. The comparison between the
two installations revealed that a pronounced difference existed in the
length of exposed threaded areas between the rod ends and the control
rods. The owner/builder of the helicopter provided the FAA inspector
with the plans and instructions provided to him by the kit manufacturer
during the assembly of the helicopter.
RHCI INVESTIGATIVE FINDINGS
This Mini-500 was first owned and built by a previous person. The new
owner was the pilot at the time of the accident. After the accident,
the FAA reported to RHCI that a rod-end that operates the collective
control had pulled out of the aluminum collective riser block due to
threads stripping out of the block. The reason was improper
installation by the builder. Instead of screwing the rod into the block
until 1/4” of threads are visible after tightening the jam nut as the
manual clearly states, this builder screwed the rod into the block only
1/4” and then tightened the jam nut. That allowed only 4 threads to
enter the block and although the rod end could not turn or back out, by
design, the threads finally failed in time due to applied forces through
normal operation. “Witness holes” are not necessary because the manual
plainly states the depth necessary for installation. RHCI points the
ability of the new pilot to still maintain control of his disabled
aircraft, and the ability of the Mini-500 to still be controlled even
with loss of this vital control function.
(8) NTSB Identification: FTW97LA339
Accident occurred Sep-09-97 at Idabel, OK
Aircraft: Roddie Mini-500, registration: N42JR
Injuries: 1 Fatal
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On September 9, 1997, at 1500 central daylight time, a Roddie Mini-500,
homebuilt helicopter, N42JR, registered to and operated by the pilot,
was destroyed while maneuvering near Idabel Airport, Idabel, Oklahoma.
The airline transport rated pilot, the sole occupant, was fatally
injured. Visual meteorological conditions prevailed and no flight plan
was filed for the Title 14 CFR Part 91 personal flight. The flight
originated from Idabel Airport at 1440. A witness, who was located at
the airport, reported that the pilot performed a run-up on the ground
before departing. The witness stated that the aircraft was operating
approximately 2000 feet above ground level and about 500 feet from the
approach end of runway 35. The witness then observed the aircraft in a
nose low attitude. Then he "saw pieces" of the aircraft "fly" from the
aircraft. The main fuselage came to rest on its right side, 1300 feet
from the approach end runway 35. The instrument panel was found 157 feet
south of the main fuselage. The tail rotor, including the vertical and
horizontal stabilizers, came
to rest 400 feet south of the main fuselage. A close friend of the
pilot, who also assisted in manufacturing the kit helicopter, reported
that new rotor blades were installed on the day prior to the accident.
RHCI INVESTIGATIVE FINDINGS
A witness reported to RHCI that the low time 50+ hours helicopter pilot
was going to attempt the first autorotation in his new Mini-500. The
witness warned him not to do so because he lacked experience in
helicopters. The witness reported that the pilot radioed to the ground
as he prepared to enter autorotation. The cause of the accident was
improper entrance into autorotation due to lack of experience in a new
and unfamiliar machine.
(9) NTSB Identification: LAX97LA326
Accident occurred Sep-13-97 at San Carlos, CA
Aircraft: Lampert M500, registration: N800GL
Injuries: 1 Minor
The pilot reported that the engine lost power, while he was holding
short of a taxi way in a hover. The helicopter landed hard on its right
skid and rolled over on its right side. Witnesses reported that they
observed the helicopter at about 20 feet AGL, when they heard the engine
abruptly cease. They then reported seeing the pilot release the
collective control with his left hand and apply full aft cyclic with
both hands. The helicopter then pitched up to an approximately 45-degree
angle while simultaneously falling. The helicopter and the airframe were
examined by an FAA airframe and powerplant mechanic, and an FAA
airworthiness inspector. No discrepancies were noted. The pilot did not
hold a rotorcraft category rating and no evidence was found that he was
endorsed for solo privileges in rotorcraft within the previous 90 days.
Probable Cause
Loss of engine power for undetermined reasons, and the pilot's improper
use of the flight controls following the loss of power. The pilot's lack
of training/certification in rotorcraft operations was a factor in this
accident.
Full Narrative
On September 13, 1997, at 1516 hours Pacific daylight time, a homebuilt
experimental Lampert M500 helicopter, N800GL, crashed on the taxiway
following a loss of engine power on approach to the San Carlos,
California, airport. The aircraft sustained substantial damage, and the
pilot, the sole occupant, incurred minor injuries. Visual meteorological
conditions prevailed at the time of the accident, and no flight plan was
on file. The local area personal flight departed San Carlos at 1500 and
was terminating at the time of the accident. In a recorded statement to
the FAA, the pilot reported that he was inbound to the airport and was
asked to hold short of a taxi way to avoid oncoming traffic. The pilot
held the helicopter in a hover and complied with the hold short
instructions. He said that at that time, "my engine went silent, the
engine RPM dropped to zero, and the aircraft began to drop rapidly." The
aircraft landed hard on its right skid and rolled over on its right
side. The tail rotor driveshaft separated from the main transmission,
and the T-tail separated from the vertical fin. In his written report,
the pilot stated that he "could have denied a straight-in [approach]
from the shoreline and entered a left-hand pattern to runway or taxiway
30 at the traffic pattern altitude thus allowing the chance of
successfully deploying autorotation technique rather than the low flight
with slight tailwind component thus being caught in the 'Dead Man's
Curve'." The pilot also reported that on entering the autorotation he
made a "slight cyclic maneuver into the wind to gain energy in the main
rotors." He said that he was, "so low that I might have smacked my tail
rotor when executing this maneuver." Witnesses stated that they observed
the helicopter at about 20 feet AGL when they heard the engine abruptly
cease. They reported then seeing the pilot release the collective
control with his left hand and apply full aft cyclic with both hands.
The helicopter then pitched up to an approximately 45-degree angle while
simultaneously falling. Initial inspection of the aircraft at the
accident site revealed that the fuel tanks were approximately 1/2 full.
The helicopter and the powerplant were examined by a certified airframe
and powerplant mechanic and a airworthiness inspector from the San Jose
Flight Standards District Office. No discrepancies were noted during the
examination. The engine was not seized and the spark plugs fired in
order with hand rotation of the crankshaft. Fuel was found in the fuel
tank and the carburetor bowl. A review of the carburetor icing
probability chart disclosed that icing conditions were not present at
the time of the accident. According to FAA Airman Records, the pilot
does not hold a rotorcraft category rating. No evidence was found that
the pilot was endorsed for solo flight in rotorcraft within the last 90
days. Repeated attempts were made to contact the pilot to schedule
further aircraft inspection with no response. The aircraft was moved
from the hangar and the owner has declined to provide its location.
RHCI INVESTIGATIVE FINDINGS
It was later reported to RHCI that the engine had no sign of stoppage.
Also a witness reported to RHCI that he could hear the engine running
until impact with the ground. From these reports, RHCI suspects that
rotor RPM was lost, and it was not properly recovered. The pilot had low
time in helicopters, and did not have a helicopter rating.
(10) NTSB Identification: LAX98LA021
Accident occurred Oct-26-97 at Long Beach, CA
Aircraft: Revolution Mini-500, registration: N7234Y
Injuries: 1 Serious
After taking off, the helicopter had climbed about 250 to 300 feet, when
the engine abruptly lost power. The pilot attempted an autorotation, but
said he was able to maintain only 80 percent rotor RPM, which was
insufficient to prevent a hard landing. The pilot reported that the main
rotor low pitch stop had recently been changed from -1.8 degree to -0.5
degree, as recommended by a factory representative. Also, the pilot
stated that he was aware of a phenomenon called "cold-freeze" (engine
seizure without over temp) that (according to him) had occurred with
other engines of this make/model. He believed there was a possible
engine seizure and that reduced settings of the rotor low pitch stops
could have resulted in low rotor RPM. No pre-impact mechanical problem
was found that would have resulted in loss of engine power.
Probable Cause
Loss of engine power and low rotor RPM for undetermined reasons. The
factory representative's recommendation to reduce the main rotor low
pitch stop (from -1.8 degree to -0.5 degree) may have been a related
factor.
Full Narrative
On October 26, 1997, at 1233 hours Pacific standard time, a Revolution
Mini-500 experimental helicopter, N7234Y, was destroyed and the
commercial pilot seriously injured when it impacted terrain following
takeoff at Daugherty Field, Long Beach, California. The aircraft had
completed one circuit of the helicopter traffic pattern and landed on
Helo Pad 3. It was then cleared for a second circuit of the helicopter
traffic pattern. The pilot stated that on the second takeoff, the engine
quit abruptly at an altitude of 250-300 feet AGL. He then attempted an
autorotation, but could get only 80 percent rotor RPM which was
insufficient to prevent a hard touchdown. (The pilot stated in his
report that he felt this was due to a recent change in the main rotor
low pitch stop from -1.8 deg. to -0.5 deg. which had been recommended by
a factory representative.) The pilot also stated that he was aware of a
phenomenon called "cold-freeze" (engine seizure without over temp) that
had happened several times with the Rotax engine. He felt that a
possible engine seizure, combined with the change in the rotor low pitch
stop, were contributing factors to the accident rather than fuel
starvation or mechanical malfunction of the helicopter.
RHCI INVESTIGATIVE FINDINGS
Upon RHCI investigation, it was discovered that the pilot was performing
a maximum performance take off which developed low rotor RPM. It was
reported that the engine did not quit, but the pilot encountered low
rotor speed and failed to recover. It was also reported that upon
examination of the engine there was no sign of stoppage, or failure.
The pilot had very low time in helicopters. It is noted that the pilot
had -1.8 degrees adjusted into his main rotor pitch. Proper pitch
should be between -.05 and -1.0 degrees. Any more than -1.0 degree will
tend to tuck the nose of the aircraft abruptly when entering an
autorotation, and also increase the possibility of a tail boom strike.
Before this accident, an RHCI test pilot flew this helicopter, performed
successful autorotations, and reported that the aircraft performed
properly.
(11) NTSB Identification: IAD98LA014
Accident occurred Nov-27-97 at Bluefield, WV
Aircraft: Jones Mini-500, registration: N8015E
Injuries: 1 Minor
On November 27, 1997, approximately 1430 eastern standard time, a Jones
Mini 500, N8015E, sustained substantial damage when the experimental
helicopter impacted the ground while maneuvering at Mercer County
Airport, Bluefield, West Virginia. The certificated commercial
pilot/builder received minor injuries. Visual meteorological conditions
prevailed. No flight plan was filed for the local flight conducted under
14 CFR Part 91.
Full Narrative
On November 27, 1997, approximately 1430 eastern standard time, a Jones
Mini 500, N8015E, sustained substantial damage when the experimental
helicopter impacted the ground while maneuvering at Mercer County
Airport, Bluefield, West Virginia. The certificated commercial
pilot/builder received minor injuries. Visual meteorological conditions
prevailed. No flight plan was filed for the local flight conducted under
14 CFR Part 91. The pilot reported that the purpose of the flight was to
"balance and adjust the flight controls." While air taxiing, the pilot
took off down wind and climbed to 50 feet AGL. The pilot stated that
"after passing through transitional lift, the rotor began to over speed,
so I reduced the throttle to maintain the rotor in the mid green." The
pilot reported that he continued and as he approached the end of the
runway, "I slowed the helicopter down and started a left turn with the
intention of flying down runway to check the head balance." The pilot
stated that, "as I started the turn I increased the throttle to the
maximum, however, the rotor RPM had deteriorated and the throttle would
not bring it back up." The pilot reported that he did not have
sufficient altitude to unload the rotor and upon ground impact, the
helicopter's left skid collapsed, rolling the helicopter onto its side
damaging the main rotor, tail boom, tail rotor, and the cockpit. The
pilot reported to the Federal Aviation Administration (FAA) Inspector
that he had thousands of hours in turbine powered helicopters, and
approximately 10 hours in reciprocating engine powered helicopters. The
FAA Inspector examined the wreckage. The examination confirmed flight
control continuity and no mechanical malfunction was found in the engine.
RHCI INVESTIGATIVE FINDINGS
The pilot developed low rotor RPM and did not properly recover.
(12) NTSB Identification: NYC98LA049
Accident occurred Dec-19-97 at Gettysburg, OH
Aircraft: Bihn Mini-500, registration: N727EB
Injuries: 1 Fatal
On December 19, 1997, about 1450 eastern standard time, a homebuilt
helicopter, a Bihn Mini 500, N727EB, was destroyed during a forced
landing and collision with terrain near Gettysburg, Ohio. The
certificated airline transport pilot was fatally injured. Visual
meteorological conditions prevailed for the personal flight that
originated at the Phillipsburg Airport, Phillipsburg, Ohio, about 1415.
No flight plan had been filed for the local flight conducted under 14
CFR Part 91. According to witnesses, the helicopter was observed in
level cruise flight, at 900 to 1,200 feet above the ground, when they
heard the engine noise of the helicopter decrease. This was followed by
the sound of two "pops," as witnesses observed the tail of the
helicopter raise up, and an object depart from the helicopter. The
helicopter then descended below tree level. According to a Federal
Aviation Administration (FAA) Inspector, examination of the wreckage
revealed that it came to rest in an open field, 90 degrees nose down,
with the forward ends of the skids imbedded about 1 foot into the
ground. The tailboom was observed to have a flattened area on the upper
surface. One rotor blade was separated from the main rotor hub, and was
located about 900 feet back along the helicopter's flight path. The
helicopter was equipped with a Rotax 582 engine. Initial examination of
the engine did not reveal a reason for the decrease in engine noise. The
pilot flew for a commercial airline and had logged in excess of 10,000
flight hours in airplanes. The pilot obtained his private pilot
helicopter certificate during July 1997. He had accumulated 59 hours in
helicopters, and all training had been conducted in the Robinson R-22.
His next helicopter flight was logged in November 1997, in the Mini 500
that he constructed. At the time of the accident, it was estimated that
he had logged about 10 hours of hover, and 2 hours of flight, in N727EB.
RHCI INVESTIGATIVE FINDINGS
The helicopter did not have an engine failure. RHCI was told by people
involved with the low time 50+ hours helicopter pilot that the purpose
for the flight was to perform his first autorotation in his new
Mini-500. He was advised by these people not to practice these
maneuvers, because it had been four months since he had last flown and a
refresher course was needed. In the opinion of RHCI, the pilot was
performing maneuvers in a new untrimmed aircraft that should have first
been done by a more experienced pilot, and that the pilot needed
additional instruction before attempting the maneuver.
(13) NTSB Identification: SEA98LA030
Accident occurred Jan-28-98 at Newberg, OR
Aircraft: Raser Mini-500, registration: N500YY
Injuries: 1 Uninjured
The pilot reported that he had just lifted off and attained an altitude
of about 20 feet, when the engine experienced a loss of power. The pilot
initiated an autorotation near the end of the airpark. The pilot stated
that the helicopter was yawed slightly to the left on touchdown to a
plowed muddy area. The right side landing skid collapsed and the
helicopter rolled over. Inspection of the engine revealed that one of
the two cylinders would not hold compression. Further inspection found
evidence of overheating and damage to the rings on the piston. The pilot
reported that the engine had been experiencing heating problems, and
that he had also modified the carburetor.
Probable Cause a power loss resulting from overtemperature of a
cylinder. The pilot's operation with known deficiencies was a factor.
Full Narrative
On January 28, 1998, at 1550 Pacific standard time, a homebuilt Raser
Mini 500, N500YY, operated by the pilot as a 14 CFR Part 91 personal
flight, collapsed the right landing skid and rolled over after
initiating an autorotation as a result of a loss of engine power shortly
after takeoff from Sportsman Airpark, Newberg, Oregon. Visual
meteorological conditions prevailed at the time and no flight plan was
filed. The helicopter was substantially damaged and the airline
transport pilot, the sole occupant, was not injured. During an interview
with a Federal Aviation Administration Inspector and subsequent written
statement, the pilot reported that he had just lifted off and attained
an altitude of about 20 feet, when the engine experienced a loss of
power. The pilot initiated an autorotation near the south end of the
airpark to a plowed muddy area. The pilot stated that the helicopter was
yawed slightly to the left on touchdown. The right side landing skid
collapsed and the helicopter rolled over onto its right side. Inspection
of the engine revealed that one of the two cylinders would not hold
compression. Further inspection of the cylinder found evidence of
overheating and damage to the rings on the piston. The pilot reported
that the engine had been experiencing heating problems, and that he had
also modified the carburetor.
RHCI INVESTIGATIVE FINDINGS
RHCI suspects that improper jetting of the carburetors was the reason
for engine failure, although the customer feels it was due to cold
seizure. It should be known that a cold seizure can only occurr in two
ways: One way is due to an insufficient warm up period upon starting,
and the other could be due to a sticking thermostat that would release
cold water to the engine head shortly after take off. This would be
indicated by a high water temperature reading in a hover, and then a
sudden drop in water temperature, causing shock cooling to the engine.
(14) NTSB Identification: MIA98LA137
Accident occurred Apr-20-98 at Lakeland, FL
Aircraft: Bennett M-500A, registration: N105WB
Injuries: 1 Uninjured
The pilot stated he was on base turn to final for a fly bye, when he
experienced a 1 to 1 vertical vibration. He informed the tower that he
was going to land, and started a deceleration. The helicopter veered to
the right, and the pilot applied left antitorque pedal. The nose started
to tuck down, then the helicopter collided with the ground and rolled
over on its right side. Examination of the helicopter flight control
system revealed a hex nut backed off the cyclic flight control push rod
bolt, and the bolt became disconnected from the control yoke teeter
block. This resulted in a loss of cyclic control.
Probable Cause
A hex nut on the cyclic flight control pushrod bolt had backed off for
undetermined reason(s) and allowed the bolt to become disconnected from
the control yoke teeter block, resulting in a loss of cyclic control and
subsequent roll over during an emergency landing.
Full Narrative
On April 20, 1998, at about 1230 eastern daylight time, a Bennett
M-500A, N105WB, experimental helicopter, registered to a private owner,
operating as a 14 CFR Part 91 personal flight, crashed on landing at the
Lakeland-Linder Regional Airport, Lakeland, Florida. Visual
meteorological conditions prevailed and no flight plan was filed. The
helicopter sustained substantial damage. The commercial pilot reported
no injuries. The flight originated from the Lakeland-Linder Regional
Airport about 1 hour before the accident.
The pilot stated he entered the traffic pattern landing to the south at
Chopper Town. He made a base turn and continued to final for a fly by,
when he experienced a 1 to 1 vertical vibration. He informed the tower
that he was going to land, and started a deceleration at 50 feet. The
helicopter started to veer to the right and he applied left antitorque
pedal. The nose started to tuck down, estimated at about 50 degrees nose
down. The helicopter collided with the ground in a nose down attitude
and rolled over on its right side.
Examination of the helicopter revealed that a flight control pushrod
became disconnected (hex nut backed off the attaching bolt) from the
control yoke teeter block, resulting in a complete loss of cyclic and
collective control of the main rotor system. Review of aircraft logbooks
revealed no maintenance had been performed on the flight control push
rod since assembly of the helicopter 106 hours before the accident.
The manufacturer for the Mini 500 stated the registered owner sent a fax
request ordering 20 Teflon DU bushings (part #0562) and 20 Teflon
washers (part #0101) that are used in the flight control system. The
request was made and filled on March 25, 1998, on invoice #25969. The
manufacturer stated in order for the registered owner to remove the
bushings and washers that it would be necessary to remove the MS21042L4
nut (part #0470) and the NAS144 bolt (part #0434) to replace the
bushings and washers.
The registered owner stated that he ordered the parts that were listed
on invoice 25969. He ordered the nuts to comply with Revolution
Helicopter Airworthiness Directive (AD) #3101998 dated March 10, 1998.
He elected to replace the control yoke (part #0024), bushings (part
#0562, 2 each) and the Teflon washers (part #0101, 4 each). The
replacement of these parts is accomplished by removing bolts #0365, and
the control transfer plate #0023. It does not require the removal of the
suspect bolt and nut assembly. Review of the Mini-500 Aircraft Assembly
and Maintenance Manual Sub-Assemblies instructions verified the
registered owner's comments.
RHCI INVESTIGATIVE FINDINGS
It was reported to RHCI by the builder and a person assisting him that
all the Teflon DU bushings in the control system had been replaced prior
to the fly-in. Just enough DU bushings and other parts were purchased
from RHCI for this purpose. To comply with AD# 3101998 only requires
two DU bushings be replaced, while the builder purchased 20. The
failure of the control system occurred because a permanent all metal
locking-nut came loose from a non-rotating area. It is suspected that
the nut and bolt were reused or not tightened at all, because of the
fact that all parts were purchased and replaced except for the nuts and
bolts. These certified nuts and bolts simply do not come loose unless
they are reused.
(15) NTSB Identification: MIA98LA161
Accident occurred May-13-98 at Villa Rica, GA
Aircraft: Revolution Mini-500, registration: N355RM
Injuries: 1 Uninjured
On May 13, 1998, about 1630 eastern daylight time, a homebuilt
helicopter, a Revolution Mini-500, N355RM, registered to a private
individual, operating as a 14 CFR Part 91 personal flight, crashed
during a precautionary landing at Stockmar Airport, Villa Rica, Georgia.
Visual meteorological conditions prevailed and no flight plan was filed.
The helicopter received substantial damage, and the ATP-rated pilot was
not injured. The flight originated from a private helipad at Cedartown,
Georgia, about 45 minutes before the accident.
Full Narrative
On May 13, 1998, about 1630 eastern daylight time, a homebuilt
helicopter, a Revolution Mini-500, N355RM, registered to a private
individual, operating as a 14 CFR Part 91 personal flight, crashed
during a precautionary landing at Stockmar Airport, Villa Rica, Georgia.
Visual meteorological conditions prevailed and no flight plan was filed.
The helicopter received substantial damage, and the ATP-rated pilot was
not injured. The flight originated from a private helipad at Cedartown,
Georgia, about 45 minutes before the accident. The pilot stated that
while in cruise flight, he noticed a "high frequency vibration/buzz
sound," together with increasing coolant and exhaust gas temperatures,
and elected to land. His intention was to perform a run-on,
precautionary landing onto the single runway at Stockmar Airport, but
the runway was in use, and he used a grassy area adjacent to the runway.
The pilot further stated he chose the grassy area because it appeared to
have been newly "bush-hogged"; however, while in the landing flare, he
realized too late that the mowed level of the grass was high enough to
conceal small obstructions. The left landing skid collided with a large,
partially hidden rock and the helicopter rotated counterclockwise
abruptly about its vertical axis approximately 240 degrees. During the
ground gyration, the main rotor severed the tailboom and the tail rotor
assembly separated from the helicopter. Postcrash inspection of the
aircraft revealed that less than a full quantity of engine coolant was
contained in the reservoir. The pilot stated the cooling system is a
closed system, and he is at a loss to explain the leakage. He states,
"It should be noted that prior to flight on this date, (accident date)
the aircraft was parked inside a hangar on a concrete floor at 7GA9,
(Whitesburg, Georgia) and no visible evidence of a leak was noted on the
floor. Further, the aircraft was landed on a concrete pad at the private
residence at Cedartown, GA and no visible evidence of a water leak was
noted on the concrete pad."
RHCI INVESTIGATIVE FINDINGS
A hose clamp was not properly tightened, and the engine lost coolant,
causing the engine to overheat. If the water level is allowed to lower
to the cylinder headcover of the engine, the engine could overheat. A
small leak may occurr while under pressure, but not leak while sitting
on the ground.
(16) NTSB Identification: FTW98LA234
Accident occurred May-20-98 at Grove, OK
Aircraft: Revolution Mini-500B, registration: N6144S
Injuries: 1 Minor
On May 20, 1998, at 0925 central daylight time, a Revolution Mini-500B
experimental helicopter, N6144S, owned and operated by the pilot as a
Title 14 CFR Part 91 personal flight, was destroyed during a forced
landing near Grove, Oklahoma. Visual meteorological conditions
prevailed, and a flight plan was not filed. The private pilot, sole
occupant of the aircraft, sustained minor injuries. The flight
originated from the Grove Municipal Airport, about 25 minutes before the
accident. According to preliminary information, the helicopter
experience a malfunction with its clutch or the clutch's drive belt. The
pilot initiated a forced landing to a high school parking lot, and
during the attempted landing, the helicopter impacted a pickup truck.
The helicopter was destroyed by a post crash fire.
Full Narrative
On May 20, 1998, at 0925 central daylight time, a Harding Revolution
Mini-500B experimental homebuilt helicopter, N6144S, owned and operated
by the pilot, was destroyed during a forced landing following the loss
of the main rotor drive near Grove, Oklahoma. Visual meteorological
conditions prevailed, and a flight plan was not filed for the Title 14
CFR Part 91 personal flight. The private pilot, sole occupant of the
aircraft, sustained minor injuries. The flight originated from the Grove
Municipal Airport, about 25 minutes before the accident.
The pilot reported that he had adjusted the alignment of the main drive
belt and engine. During the ensuing personal/test flight of the
helicopter, while at a cruising altitude of 1,350 feet MSL, he felt a
"sudden hesitation and [smelled the] odor of smoke." While he was
"determining if [a] serious malfunction existed," the helicopter
experienced a loss of main rotor drive and altitude, "along with a
stronger burning odor." The pilot initiated an autorotation to a field
adjacent to a school. However, prior to reaching the intended landing
area, the helicopter struck a parked pickup truck, "flipped over, landed
in [the] field and started on fire." The helicopter was destroyed by the
postimpact fire. The pilot had accumulated a total of 59 flight hours
in helicopters, of which 14 hours were accumulated in his homebuilt
helicopter.
RHCI INVESTIGATIVE FINDINGS
The helicopter did not have a clutch failure. The drive belt was not
properly aligned, causing a belt failure. Information about proper
alignment was supplied on the Service Information Letter #040196.
(17) NTSB Identification: NYC98LA154
Accident occurred Jul-26-98 at Shermans Dale, PA
Aircraft: Johnson Revolution Mini-500, registration: N805JJ
Injuries: 1 Uninjured
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On July 26, 1998, about 1800 Eastern Daylight Time, a homebuilt
Revolution Mini-500 helicopter, N805JJ, was substantially damaged during
a forced landing at Yost Airport (32PA), Shermans Dale, Pennsylvania.
The certificated private pilot was not injured. Visual meteorological
conditions prevailed at the time of the accident. No flight plan was
filed for the personal flight conducted under 14 CFR Part 91. According
to the pilot's written statement, after about 45 minutes of flight, he
entered the traffic pattern at his destination, and descended during
both the base leg and final approach. While on the final approach, at 20
to 30 feet of altitude, the engine "stopped dead ... no sputtering, no
sign, just nothing." The helicopter landed hard, the left skid
collapsed, the main rotor struck the tail boom, and the helicopter
rolled over on its left side. According to a Federal Aviation
Administration (FAA) Inspector, the fuel tank was approximately 1/3
full, and there was fuel in the glass bulb along the fuel line. There
was sufficient engine oil in the oil tank and the throttle linkage was
intact.
RHCI INVESTIGATIVE FINDINGS
From RHCI’s investigation and after discussing the accident with the
pilot, the cause of engine failure was seizure due to improper jetting.
Customer was experimenting with the different sizes of jets, and at
the time of the accident, he had installed 155 main jets. If the proper
needle jet and needle position are not installed according to RHCI’s
instructions, AD’s and advisories, the engine will seize, and most
likely this would happen in a descent where the improper needle jet
arrangement will tend to lean the mixture the most.
(18) NTSB Identification: IAD98LA092
Accident occurred Aug-11-98 at Northampton, PA
Aircraft: Austin Revolution Mini-500, Registration: N2XK
Injuries: 1 Fatal
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On August 11,1998, at 1832 eastern daylight time, a homebuilt Revolution
Mini 500 helicopter, N2XK, was destroyed during collision with terrain
following an uncontrolled descent near Northhampton, Pennsylvania. The
certificated commercial pilot was fatally injured. Visual meteorological
conditions prevailed for the maintenance test flight that originated at
Bangor, Pennsylvania, approximately 1800. No flight plan was filed for
the flight conducted under 14 CFR
Part 91. In a telephone interview, one witness stated his attention was
drawn to the helicopter because it sounded unusual. He said the
helicopter was maneuvering approximately 200 feet in the air. The
witness said: "I saw it circle around but it didn't sound too good. I
heard it making these weird noises. It stopped in the air and then
turned towards my house. I heard it go 'pow' then another sharp 'snap'.
It sounded like a gunshot. Then I saw this piece flying. The helicopter
rotated approximately one-quarter turn, the tail came up, the nose
dropped, and then the aircraft fell out of sight." In a telephone
interview, a second witness said his attention was drawn by the sound.
He stated: "It sounded like a helicopter, but it had a funny sound, it
had a rat-a-tat-tat sound. I couldn't see it, then I saw him make a
right hand turn heading due west gaining altitude. I heard a
'poof-poof'...Just the sounds of the rotors didn't sound normal. I heard
the lighter 'pop' and then the louder 'pop'." The witness stated the
helicopter then descended behind a tree line out of view. The wreckage
was examined at the site on August 12, 1998, by a team of Federal
Aviation Administration (FAA) Aviation Safety Inspectors. All major
components were accounted for at the scene. According to one Inspector's
statement: "The helicopter wreckage showed a vertical impact where the
aircraft wreckage remained within a very confined area. No wreckage was
more than a few feet from the fuselage. The only part of the aircraft
not within the main fuselage was one main rotor blade which was
discovered over 400 feet from the aircraft. Upon further investigation
of the crash site, I observed that the pitch horn (a casting) was
fractured on one of the main rotor hubs and disconnected. The blade yoke
was still attached but only about twelve inches of the blade was
attached. This part matched with the blade assembly that was over 400
feet from the wreckage. The rest of the hub assembly was found intact
and all control rods and assemblies were attached. The mast showed no
signs of mast bumping or deformation. The tailboom assembly and tail
rotor assembly showed no signs of main rotor blade contact nor prior
damage before impact...the pitch change rod to the hub with the missing
main rotor blade was loose and the jam nuts to the rod and bearings were
loose and not torqued at all." On August 12, 1998, the Inspector visited
the location where the helicopter was hangared and maintained. He found
the construction manual for the helicopter opened to the section for the
rigging and balancing of the rotor system and a copy of the "Revolution
Helicopter Airworthiness Directive (AD) #09031997...New Dynamic Main
Rotor System Balancing Procedures." According to Revolution Helicopter
Corporation, Inc., the AD was "...Urgent (Must Be Complied With Before
Further Flight)." The FAA Inspector interviewed the pilot's son
regarding any work performed on the helicopter and the purpose of the
flight. According to the Inspector's report: "His son informed me that
he was assisting his father with rotor tracking by holding the tracking
flag and his father was adjusting the blade track with the pitch change
links. The son left prior to his father finishing the ground portion of
the checks and when he returned the aircraft and his father were gone."
Portions of the main rotor system were forwarded to the NTSB Materials
Laboratory in Washington, D.C. for further examination.
RHCI INVESTIGATIVE FINDINGS
RHCI was told by the NTSB that they found the pitch change rod to the
hub with the missing main rotor blade was loose and the jam nuts to the
rod-ends and bearings were loose and not torqued at all. The pilot
didn’t finish tightening the jam nuts on the pitch link change rods. The
pilot took off to make a run, and in forward flight, the rod-ends
screwed loose causing the blades to go so far out of track that the
aircraft could no longer be controlled, causing rotor failure.
(19) NTSB Identification: MIA98LA236
Accident occurred Aug-30-98 at Hattiesburg, MS
Aircraft: Hall Revolution Mini-500, registration: N9GH
Injuries: 1 Uninjured
On August 30, 1998, about 1500 central daylight time, a Hall Revolution
Mini 500 homebuilt helicopter, N9GH, registered to an individual, landed
hard at Hattiesburg, Mississippi, while on a Title 14 CFR Part 91
personal flight. Visual meteorological conditions prevailed at the time
and no flight plan was filed. The airline transport-rated pilot was not
injured and the helicopter received substantial damage. The flight was
originating at the time of the accident.
Full Narrative
On August 30, 1998, about 1500 central daylight time, a Hall Revolution
Mini 500 homebuilt helicopter, N9GH, registered to an individual, landed
hard at Hattiesburg, Mississippi, while on a Title 14 CFR Part 91
personal flight. Visual meteorological conditions prevailed at the time
and no flight plan was filed. The airline transport-rated pilot was not
injured and the helicopter received substantial damage. The flight was
originating at the time of the accident.
The pilot stated that as he hovered forward at a brisk walk, he heard
the low rotor RPM horn and reduced the collective control. The
helicopter descended rapidly and touched down on the "toes" of the
skids. The helicopter bounced back into the air and the cyclic control
grip separated from the cyclic control stick. The cyclic control stick
moved to the full aft position and the main rotor blades contacted the
tail boom.
RHCI INVESTIGATIVE FINDINGS
The pilot allowed the aircraft to enter into a low rotor RPM condition
from which sufficient lift could not be obtained to slow the aircraft’s
forward speed and cushion the landing. According to the pilot, the
cause of damage was control grip separating from the cyclic control
stick which moved uncontrollably to the aft position, allowing the
rotorblades to contact the aircraft tail boom. If this was the case,
then damage may have been adverte if the cyclic grip had been glued in
place as called for in the assembly manual.
(20) NTSB Identification: CHI98LA334
Accident occurred Sep-08-98 at Eden Prairie, MN
Aircraft: CulverMini-500, registration: N6269R
Injuries: 1 Uninjured
On September 8, 1998, at 1900 central daylight time (cdt), a
Culver-Revolution Mini 500, N6269R, piloted by a private pilot, was
substantially damaged when it collided with the ground shortly after a
total loss of power while hovering. Visual meteorological conditions
prevailed at the time of the accident. The 14 CFR Part 91 personal
flight was not operating on a flight plan. The pilot reported no
injuries. The flight departed Eden Prairie, Minnesota, at 1850 cdt.
Full Narrative
On September 8, 1998, at 1900 central daylight time (cdt), a
Culver-Revolution Mini 500, N6269R, piloted by a private pilot, was
substantially damaged when it collided with the ground shortly after a
total loss of power while hovering. Visual meteorological conditions
prevailed at the time of the accident. The 14 CFR Part 91 personal
flight was not operating on a flight plan. The pilot reported no
injuries. The flight departed Eden Prairie, Minnesota, at 1850 cdt.
The pilot said he had been hover-taxiing the helicopter between the
approach end of runway 36 and the south taxiway for runway 09R. He said
he had been hover-taxiing for about 10-minutes when "...the engine
stopped unexpectedly [and it] settled to the runway and rolled over."
The on-scene investigation revealed no anomalies with the airframe,
engine or control system that would prevent flight. Examination of the
fuel system revealed a silicon-type sealant had completely blocked the
supply side of the fuel filter.
According to the pilot/builder, he had used this material as a seal
between the helicopter's fuel tank filler neck flange and fuel tank
body. The helicopter's kit manufacturers instruction states that the
builder is to "Place a 1/8-inch bead of MA300 from the adhesive kit
around [the] hole circle through the centerline of [the mounting]
holes." A copy of these instructions are appended to this report.
The kit manufacturer was contacted regarding the accident and
pilot/builders use of the silicon-type material. The manufacturer
representative was asked if there were any warnings in the construction
manual against the use of the silicon-type sealant as the builder had
done. He said there were no warnings, only instructions to use the MA300
material. He said the MA300 is an epoxy- type glue/sealant that does not
break down when contacted by gasoline. He said the silicon-type sealant
will dissolve when contacted by gasoline. The IIC suggested the company
publish a manual change or communicate the need to use only the sealant
recommended by them. The company agreed and said they would put a
notice in the next builder's newsletter. A copy of the company's
December 1998 newsletter is appended to this report.
RHCI INVESTIGATIVE FINDINGS
This report was taken by phone from Randy Culver on Thursday, September
10, 1998, by Rick Stitt, RHCI Project Engineer.
The aircraft was in translational lift with an indicated airspeed of 15
MPH. The engine lost power and the aircraft landed hard on the back of
the skids and rolled over. The pilot did not receive any injury. The
customer determined engine power loss was caused by silicone installed
on the metal flange of the fuel tank neck, that came loose and plugged
the fuel filter. The RHCI instructions (Sect. 5 page 21, Assy
Instruction #4) recommend using MA300 in a 1/8" bead around the flange
through the center line of each hole and securing with rivets and washers.
(21) NTSB Identification: CHI98FA353
Accident occurred Sep-19-98 at Cahokai, IL
Aircraft: Barklage Revolution Mini-500, registration: N611AB
Injuries: 1 Serious
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On September 19, 1998, at 1330 central daylight time (cdt), a Barklage
Revolution Mini 500, N611AB, operated by a commercial pilot, was
destroyed when on initial climb, the helicopter's engine lost power.
During the subsequent emergency landing, the helicopter impacted into a
soybean field. Visual meteorological conditions prevailed at the time of
the accident. The personal flight was being conducted under 14 CFR Part
91. There was no flight plan on final. The pilot sustained serious
injuries. The cross-country flight originated at Cahokia, Illinois, at
1323 cdt, and was en route to St. Charles, Missouri.
RHCI INVESTIGATIVE FINDINGS
It has been reported to RHCI by the NTSB and Rotax that a foreign object
was dropped into the crank case, and worked to the top of the piston and
failed both spark plug tongues causing the engine to quit. It was
reported to RHCI that upon take off the Mini-500 climbed to an altitude
of 200 feet, and when crossing over a power line complex experienced a
power lost. The pilot had not gained enough altitude to clear the wires,
and needed to extend his autorotation in order to reach a suitable
landing site on the other side. This maneuver used all available rotor
inertia, causing the rotor system to slow in RPM to a point where the
autorotation could not be continued.
(22) NTSB Identification: LAX99LA004
Accident occurred Oct-04-98 at Moorpark, CA
Aircraft: Burson Mini-500, registration: N418MB
Injuries: 1 Fatal
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On October 4, 1998, at an unknown time, a Burson Mini 500, N418MB,
crashed in hilly terrain near Moorpark, California. The aircraft was
destroyed, and the private pilot, the sole occupant, suffered fatal
injuries. Visual meteorological conditions prevailed for the afternoon
of the flight and no flight plan was filed, nor were any ATC services
provided. The pilot's daughter reported that she accompanied the pilot
to the takeoff/landing site and helped reinstall the main rotor blades,
which had been removed to trailer the helicopter. She stated that her
father reported that he would fly over the park where she was playing
baseball, and would subsequently fly over the family residence, in
approximately 45 minutes. She left the site at 1417. The daughter
further recalled that the pilot reported that he would be flying for 1
1/2 to 2 hours. She never saw or heard him fly over the park, and he was
not seen over the family house. The pilot's wife reported the pilot as
missing and an ALNOT was issued at 2040. The Ventura County Sheriff
located the wreckage at 0300 on October 5, 1998.
RHCI INVESTIGATIVE FINDINGS
RHCI was told that the pilot had recently completed his helicopter
training, and at the time of the accident had flown his Mini-500 for 33
hours. His total helicopter time was less than 100 hours. It was
reported that the pilot was flying through a canyon in Southern
California during gusty conditions. Upon investigating the crash, it was
found that all controls were intact, gas and oil were in the tanks,
carburetors and engine were running and had no signs of seizure. It is
suspected that the gusty conditions blowing over the canyon walls caused
the low-time pilot to over control the aircraft, causing the accident.
(23) NTSB Identification: MIA99LA017
Accident occurred Oct-26-98 at Hickory, NC
Aircraft: Reinhold Revolution Mini-500, registration: N500GQ
Injuries: 1 Uninjured
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On October 26, 1998, about 1615 eastern standard time, a Reinhold
Revolution Mini 500, N500GQ, registered to an individual, made a hard
landing following loss of engine power near Hickory, North Carolina,
while on a Title 14 CFR Part 91 personal flight. Visual meteorological
conditions prevailed at the time and no flight plan was filed. The
helicopter received substantial damage and the airline transport-rated
pilot was not injured. The flight originated from Hickory, North
Carolina, the same day, about 1600. The pilot stated that the engine
lost power do to a seized rear cylinder. While making a forced landing
in a field, the helicopter touched down on uneven terrain and the main
rotor blades contacted the tail boom and ground.
RHCI INVESTIGATIVE FINDINGS
The engine was not taken apart to determine the reason why it quit,
therefore, engine failure is undetermined. It is known that shortly
before this accident, this engine had failed earlier. It was then sent
to a Rotax overhaul facility, and found to have a hole burnt in the
pistons, due to pre-detonation from low octane fuel. It is believed
that the pilot obtained fuel from the same source as before, causing the
second engine failure.
(24) NTSB Identification: CHI99LA026
Accident occurred Nov-06-98 at Clinton, MN
Aircraft: Tomschin Mini-500, registration: N316AZ
Injuries: 1 Uninjured
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On November 6, 1998, at 0923 central standard time (cst), a Tomschin
Mini 500, N316AZ, piloted by a non-certificated individual, sustained
substantial damage when while in cruise flight, the helicopter struck a
power line. The helicopter subsequently impacted into a farm field, 4
miles east of Clinton, Minnesota. Visual meteorological conditions
prevailed at the time of the accident. The personal flight was being
conducted under 14 CFR Part 91. No flight plan was on file. The
individual operating the helicopter at the time of the accident reported
no injuries.
RHCI INVESTIGATIVE FINDINGS
Pilot was performing flight testing for forward balance. He was flying
about 70 mph in a hazy overcast. He flew into a power line which
contacted the aircraft on the mast, between the main blades and turtle
deck. Pilot was able to stay in control until he was about 4 feet above
the ground and 500 feet from the contact point. Aircraft landed on the
skids and sustained blade and tail boom damage.
(25) NTSB Identification: IAD99FA023
Accident occurred Nov-29-98 At Midland, VA
Aircraft: Armbruster Mini-500, registration: N500GH
Injuries: 1 Fatal
This is preliminary information, subject to change, and may contain
errors. Any errors in this report will be corrected when the final
report has been completed.
On November 29, 1998, about 1515 eastern standard time, a homebuilt Mini
500, N500GH, was destroyed during a collision with trees near Midland,
Virginia. The certificated private pilot/owner/builder was fatally
injured. Visual meteorological conditions prevailed for the local flight
that originated from the Manassas Airport (HEF), Manassas, Virginia. No
flight plan was filed for the personal flight conducted under 14 CFR
Part 91. A family member reported the pilot missing after not returning
from his normal 40 to 45 minute flight. The pilot's vehicle remained
parked outside his hangar the next morning, and the Federal Aviation
Administration issued an Alert Notice. The Civil Air Patrol's search
discovered that tower personnel at HEF recorded the helicopter taking
off at 1400. Witnesses stated that they saw the helicopter near Leesburg
Airport, Leesburg, Virginia, about 1430, and near Nokesville, Virginia,
about 1500, on November 29th. The helicopter was located on December 2,
1998, about 1530, in a wooded area approximately 1/4 mile
north/northeast of the Warrenton-Fauquier Airport, Warrenton, Virginia.
A survey of the debris field discovered that the initial impact point
was the top of a 50-foot tall tree. Tree limbs, measuring 4 to 6 inches
in diameter, were cut horizontally and found near the base of the tree.
One of the helicopter's rotors was lying on the ground near the tree;
the other was snagged on a fracture tree limb about 30 feet above the
ground. The main wreckage was lying on its left side between two trees 5
feet apart, and about 35 feet south of the initial impact point. All
major components of the helicopter were found at the accident scene.
Examination of the flight controls revealed continuity at the time of
impact. The engine logbook indicated that in August 1998, at 200.4 hours
on the Hobbs meter, the owner replaced both pistons, rings, wrist pins,
rod bearings, thermostat, and head o-rings. The Hobbs meter in the
wreckage read 218.7 hours. Inspection of the engine revealed two
different types of spark plugs were utilized, one of each type in the
two cylinders. The spark plugs were wired such that one magneto fired
one type of spark plug. Rotation of the crank shaft revealed 4 point
scuffing on the cylinder and the Power Take-Off (PTO) piston.
RHCI INVESTIGATIVE FINDINGS
The pilot had installed his Mini-500 “Power Enhancement Package” (PEP),
and against RHCI’s severe warnings, chose not to use the provided jet
package containing a 2.76 needle jet. Instead he installed a 2.78
needle jet which meant that he needed a 155 main jet to achieve the
proper EGT in hover. RHCI informed the pilot that the engine would
seize with this small main jet, when at high-power settings it could not
supply sufficient fuel to the engine, causing it to heat and seize. The
main jet should have been a 165 or 170. Also, he had erroneously set
the needle in the third position on the cylinder that seized; the other
was correct in the fourth position. He was flying over a forest when
the engine seized, and autorotated into a 50-foot tall tree. The impact
broke the mast and the aircraft fell and landed upside down on the ground.
Unreported Accidents:
The following is a summary of unreported accidents and incidents not
only in the U.S., but also in foreign countries. These accidents were
reported to RHCI by the pilots, witnesses, and friends, but not to the
NTSB, FAA, or the legal authorities in each respective country.
Therefore, in order to protect the privacy of those involved, RHCI is
only providing a description of the events.
Report 1
Conditions Day
Wind Unknown
Temperature 85 deg. F
Elevation 300 ft
Pilot stated that he was demonstrating the aircraft for someone. He had
been flying several traffic patterns and had come to a 10 ft. hover. He
suddenly lost tail rotor control. The aircraft hit the ground hard while
still spinning to the right. One skid collapsed and the aircraft rolled
onto its side. The aircraft sustained typical roll over damage. Pilot
received no injuries.
Pilot had reinstalled the tail rotor assembly after trailering the
aircraft from Oshkosh. He forgot to tighten the jam nut that secures the
tail rotor push pull control cable to the tail rotor gear box mounting
plate. When the jam nut finally worked its way off, tail rotor control
was lost.
Report 2
Conditions Day
Wind Unknown
Temperature Unknown
Elevation Unknown
The designated pilot for this aircraft failed to make sure there was
enough fuel before taking off. After flying for a while, pilot realized
he was out of gas and was forced to make an emergency landing. Pilot
failed to autorotate successfully, and therefore, aircraft sustained
typical rollover damage. Pilot received no injuries.
Report 3
Conditions Day
Wind Gusting to 20-25 mph
Temperature 80-90 deg. F
Elevation 200 ft
There was a witness to the incident. The witness stated that they were
doing track and balance. The pilot was hovering the aircraft and the
witness was working the balance equipment. The witness said that the
aircraft started to oscillate from side to side a couple of times and
then rolled over. The aircraft actually sustained less than typical
damage. Probable cause of the incident is that the pilot was hovering
the aircraft in winds that exceeded his experience level. The aircraft
has now been repaired and is again flying. The pilot had accumulated 50+
helicopter hours and received no injuries.
Report 4
Conditions Day
Wind Unknown
Temperature Unknown
Elevation Unknown
Pilot stated that he was returning to the airport and was on a long
final when he started to lose rotor RPM and could not recover. The
aircraft hit the ground short of the airport at an estimated 20-30 mph.
The aircraft rolled three times and broke into several pieces. The
aircraft received heavy damage as would be expected. Pilot received no
injuries.
Pilot tried to blame the transmission for the loss of rotor RPM. The
transmission was shipped to RHCI and no damage other than crash related
damage could be found. Further conversations with the pilot indicated
that he let his rotor RPM get low and panicked. He said that he applied
full throttle but the RPM would not recover. He could not remember ever
lowering the collective. More than likely, he saw the ground rushing up
at him and raised the collective.
Report 5
Conditions Day
Wind Unknown
Temperature Unknown
Elevation Unknown
The details of this accident are a little sketchy. We have heard two
different stories. One, that the controls jammed, and the other that the
pilot lost rotor RPM and could not recover. We may never know the truth.
The aircraft did land hard and roll over, sustaining typical rollover
damage. The pilot was a low-time pilot and received no injuries.
Report 6
Conditions Day
Wind Unknown
Temperature 85 deg. F
Elevation 200 ft
The second-hand word from a spectator is that the pilot was on take off
and let his RPM get low and could not recover. He landed hard,
collapsing a skid and the aircraft rolled onto its side. Aircraft
suffered typical rollover damage. The pilot had accumulated 59
helicopter hours and received no injuries.
Report 7
Conditions Day
Wind Unknown
Temperature Unknown
Elevation 1000 ft
Pilot stated the aircraft had approximately five hours of flight time.
The pilot was practicing slide on landing from a hover to the grass
beside the runway. One of the skids got caught on an aircraft tie down
that was hidden in the grass. The aircraft tipped forward and the main
rotor blades contacted with the ground. The aircraft came to rest on its
left side. The aircraft sustained typical rollover damage. The pilot
received no injuries.
Report 8
Conditions Day
Wind 8 to 12 mph
Temperature 80 deg. F
Elevation 300 ft
The pilot stated that he departed from a local gas station after
refueling. He saw power lines in his departure path and decided to do a
180 degree turn. In doing so, he turned downwind and experienced
settling with power from about 20 feet and failed to recover properly.
On impact the helicopter’s right front leg bent enough for the main
blades to strike the ground. The aircraft did not roll over and no
injuries occurred.
Report 9
Conditions Day
Wind 25 to 35 mph
Temperature 75 deg F
Elevation 142 ft
The low time pilot had just hovered his helicopter onto a trailer with
no incident. As the engine and blades wound down, a gust of wind struck
the ship from the side and blew it off the trailer. The aircraft
sustained typical rollover damage. No injuries occurred.
Report 10
Conditions Day
Wind Unknown
Temperature Unkown
Elevation Unknown
The pilot stated that while in cruise flight at about 300 feet above
rough terrain the engine suffered a "partial" power loss. (There is no
such thing as "partial" power loss in a piston engine, and therefore,
RHCI feels that the pilot allowed the rotors to lose RPM). The pilot
spent some time trying to recover power before setting up for an
autorotation. He made a 180 degree turn on the way down. He flared early
and ran out of rotor RPM at about 15 feet above the ground. The machine
landed very hard on sloping ground and then rolled over. The aircraft
sustained typical rollover damage. No injuries occurred.
Report 11
Conditions Day
Wind Light
Temperature Unknown
Elevation Unknown
The pilot had just completed his Mini-500. While he was hovering the
helicopter for the first time to break in the engine, he drifted off the
tarmac onto a grassy area. One skid caught a mound of grass that was
protruding up. The helicopter experienced dynamic rollover and sustained
typical rollover damage. No injuries occurred.
Report 12
Conditions Day
Wind Unknown
Temperature Unknown
Elevation Unknown
While practicing autorotations, the low-time pilot inadvertently let the
rotor RPM wind down at the bottom end of the auto. There was not enough
time to regain RPM before touchdown. The aircraft impacted then rolled
over. The aircraft sustained typical rollover damage. No injuries occurred.
Report 13
Conditions Day
Wind 10 mph
Temperature 80 deg. F
Elevation -11 ft
The 50+ hours helicopter pilot stated that after fueling the aircraft,
he departed, and then immediately turned 90 degrees left into a
crosswind for a two-hour trip. Just before he reached translational lift
at a height of about four feet, he let the rotor RPM wind down to where
he was behind the power curve and starting to lose lift. He thought
about doing a slide-on landing, but decided to do a quick stop instead.
At that point he did not have enough RPM to successfully execute a quick
stop. The aircraft slammed down bending the right skids and then rolled
over. No injuries occurred.
Report 14
Conditions Day
Wind 3 to 5 mph
Temperature 80 deg. F
Elevation Unknown
On approach the low-time pilot let the rotor RPM wind down to the bottom
of the yellow. On landing, the helicopter impacted hard enough to bend
the landing gear causing the aircraft to roll over. The aircraft
sustained typical rollover damage. No injuries occurred.
Report 15
Conditions Day
Wind 20 mph
Temperature 59 deg F
Elevation 2000 ft
The low-time pilot reported he was in very slow flight down wind at
about 30 feet when he let the rotor RPM deteriorate. He lowered the
collective for an autorotation, then misjudged the time to raise the
collective. The aircraft impacted the ground hard enough to bend the
legs and then rolled over. The aircraft sustained typical rollover
damage. No injuries occurred.
Report 16
Conditions Day
Wind Unknown
Temperature Unknown
Elevation Unknown
The pilot decided to go flying one afternoon, but misplaced his ground
wheels and could not remove the aircraft from the garage. He thought he
could fly it out, without harming anything. As the helicopter reached
the door, the down wash pulled the door down on top of the rotors. No
pilot injuries occurred, but the helicopter sustained typical garage
door damage. (There have been more than five different stories about
this accident, and therefore, RHCI feels that the truth is not
completely known.)
Other Accidents:
1) Pilot landed in a field with several other Mini-500s coming in behind
for landing. Pilot got out of his aircraft while engine was running and
blades were turning, and did not tighten the collective friction. He
was motioning to the others where to land, and much to the pilot’s
surprise, the aircraft took off by itself, and crash. It is recommended
that any aircraft never be unattended when the engine is running.
2) Builder failed to change the center of gravity of the aircraft after
a much heavier pilot finished flying. When he picked the aircraft up to
a hover, the tail rocked back and the tail rotor struck the ground.
Minor damage to one tail rotor blade.
3) Builder failed to remove the packing material from inside the tail
boom after trailering the aircraft. While in a hover, the packing
material became entangled in the tail rotor drive shaft and severed the
drive shaft. The aircraft landed hard and bent the landing gear and tail
boom supports.
Non-Flight Related:
The following were incidents non-flight related, and they have only be
included to provide you with helpful information as to what to watch for
when you are on the ground and not flying your aircraft:
1) The pilot reported that while trailering his Mini-500 home one
evening, his car collided with a large deer. The deer flew over the top
of the car and impacted the front cabin section of the Mini-500, causing
extensive damage.
2) Builder claimed that he was cleaning the engine compartment with a
flammable solvent. He then claimed that he dropped a screwdriver into
the engine compartment, and then went to the house for something. He
said he then heard the electric starter of the aircraft making noise,
and then saw flames coming from the aircraft. The customer claimed that
the screwdriver made contact with a solonoid causing sparks and the
electric starter to turn, and the aircraft was destroyed by fire. It is
noted that the aircraft was fully insured, and the customer had been
advertising it for sale.
3) Pilot reported that he landed and exited the cockpit and was waiting
for a friend. At the same time, a Piper Warrior Pa 28 was parking, and
its right wing collided into the left side of the Mini-500. The Piper's
wing, weighing about 550 pounds with a fuel tank, knocked the Mini-500
four feet from where it was parked. The only damage found in the
Mini-500 was a dent above the collective side in the main cockpit
structure side wall and between the two left front door hinges. The
Piper Pa 28's right wing was a total loss.
