MT 05 Accident Witbank

[M I Claase]

Pilot in hospital with dislocated shoulder and passenger has minor injuries. Accident happened last Saturday on take off. Gyro badly damaged. This I heard secondhand. Can anybody shed some more light on this incident?

[redrocket]

Witbank newspaper reported the gyro had a loss of power!

[C205]

Hi Malcolm
Was there when it happened, but sorry don't know much about gyros and did not actually see the accident. Some of our guys did though and asked me to call an ambulance as a 'helicopter' had crashed. We had a doctor and paramedic at the club and they went out to the scene as well.
Witnesses (inc. air force personnel) told me they saw a cloud of dust just as gyro rotated. Gyro rolled over next to the runway. Photo in Witbank News. Pilot told bystanders he lost power on take-off.
Regards
J (your old hangar mate).

[Gyronaut]

Thank heavens they both survived!
I wish them a speedy recovery.

Something happened that shouldn't have and it could happen to anyone of us - unless we learn from each other. I would really like to know a little more so we can all learn from this, hopefully the pilot is up to telling us himself, soon.

Len

[old no 7]

Thank heavens they both survived!
I wish them a speedy recovery.

Something happened that shouldn't have and it could happen to anyone of us - unless we learn from each other. I would really like to know a little more so we can all learn from this, hopefully the pilot is up to telling us himself, soon.

Len

Fully agree with your logic that sharing information and experiences saves lives in the future.
Unfortunately some pilots may feel embarrassed by their incidents and not want them in the public domain. That I understand and it is their right for their privacy to be respected.
I do however have a problem when distrubutors promote silence and almost secrecy at incidents involving their brands for fear of a negative image to their brand. (Yes I can make this claim)
I am not suggesting that either of these apply in this situation. Maybe it is too soon to expect more info while investigations and insurance claims are being dealt with, but there are a lot more incidents happening than we get to hear about.
Instead of hiding these, we should be learning from them.

[C205]

Pic of the gyro

[Gyronaut]

That'll buff right out

I look forward to hearing what really happened?
Engine was clearly running, judging by the damage to the prop.
Blade flap usually results in a roll-over to the left in counter clock-wise rotating rotors.
NOT Speculating, just asking.

Len

[old no 7]

That'll buff right out

I look forward to hearing what really happened?
Engine was clearly running, judging by the damage to the prop.
Blade flap usually results in a roll-over to the left in counter clock-wise rotating rotors.
NOT Speculating, just asking.

Len

T/O behind the power curve?
(I am speculating)

[Condor]

What is the lesson from this unfortunate accident?

ROTOR MANAGEMENT, ROTOR MANAGEMENT AND ONCE AGAIN ROTOR MANAGEMENT.

The passenger in this accident wrote a "uitk$%&" letter to the factory in Germany to state how unstable gyro's are and something should be done about it.

I invite this passenger for a 10 min private discussion to understand the basics and then he will also understand that gyro's are NOT unstable.

I can’t quote every word of his letter but the facts almost clarify the whole story.

These are the basic facts from his letter:

The pilot did his checks and pre-rotated to 200rpm as per the book.

They started their take-off roll and at 70mph the pilot realised all was not well and discovered the rotor rpm has slowed down to 195rpm. At this stage he decided to abort.

The next moment the gyro jump in the air and landed on its side to skid along the runway for almost 70m.

Now we can just wonder why did blade-flap still tipped the gyro over.

Did the pilot pull the stick back to stop the gyro?

Did he...........

Who knows?

To me it is clear that a momentarily laps in pilot concentration (not pulling the stick back before take-off) caused this accident, which bring me to my opening statement of ROTOR management.

There is one other aspect I need to stress and this happened twice to me fortunately without any damage.

This pilot was showing a fellow aviator how nice it is to fly a gyro.
I was taking my friend’s wife for a flip and was so busy explaining how nice it is that I forgot to open the gills on the radiator, in the process came close to cooking the engine beyond repair.

When you do a "show-off" (I don’t mean this in any cowboy way) be super aware of you procedures as things bite you when your mind is busy with your passenger that you want to impress.

Trust we can all learn something from this unfornate accident and wish the pilot a speady recovery.

[Gyronaut]

High Speed Blade Flap would be my guess. [so shoot me for speculating so shamelessly, I dont care ]

Statistically it is evident that the following is true:

#1 cause of gyro accidents: Flying into Wires
#2 cause of gyro accidents: Flying behind the power-curve (too low too slow)
#3 cause of gyro accidents: Rotor mismanagement on the ground

Fatality probability is higher the lower the number above.

Gyro's all essentially behave the same, no matter what the make or model. This is not about a specific manufacturer or configuration. All gyro's will experience the same given the same circumstances.

From the FAA rotorwing handbook:

"BLADE FLAP
On a gyroplane with a semi-rigid, teeter-head rotor system,
blade flap may develop if too much airflow passes
through the rotor system while it is operating at too low
r.p.m. This is most often the result of taxiing too fast
for a given rotor speed. Unequal lift acting on the
advancing and retreating blades can cause the blades to
teeter to the maximum allowed by the rotor head
design. The blades then hit the teeter stops, creating a
vibration that may be felt in the cyclic control. The frequency
of the vibration corresponds to the speed of the
rotor, with the blades hitting the stops twice during
each revolution. If the flapping is not controlled, the
situation can grow worse as the blades begin to flex and bend."

The higher the speed the more violent the flap. At 60mph the average gyro's rotor speed should be around 350+. Any less angle of attack to lift the machine off the ground at that speed is very risky. Remember gyroscopic-precession will happen 90deg later. In a counter-clockwise rotation system, high speed blade-flap will probably result in a roll-over to the left (I think).

"Decreasing the rotor disc angle of attack with forward cyclic (stick full forward) can reduce the excessive amount of airflow causing the blade flap. This also allows greater clearance between the rotor blades and the surface behind the gyroplane, minimizing the chances of a blade striking the ground."

This is basic stuff actually. If you understand the aerodynamics it can't happen to you. You wouldn't jump off a cliff with a half inflated para-glider wing would you? Open the 'chute' with the stick back, balance , hold, then take off safely.

Question 10 in our Student Pilot Licence exam is:

10. When rotor flap is experienced, what can be done to prevent it from continuing or getting worse?
a) Stick back, power off and hit the brakes
b) Stick forward increase power and apply rotor brake
c) Stick forward, cut power and hit the brakes

The answer has to be right before the student officially commences with his training. If he doesn't get it by the time he wants to start training, he should go play golf.

The value of practicing wheel balancing during instruction cannot be over-supported and should form part of the taxiing syllabus.

If you play a game with yourself and lose a point every time the nose wheel touches down after initial lift off, or the tail wheel drags, then you can begin to score your own ability. The same applies on landing. If your attitude and airspeed are right for the round-out & hold-off, the main wheels will touch first, steering with pedal to remain on the line you hold the nose off until the stick is full back and the nose-wheel 'plops' down on its own. You will be stationary by then. 10 points.
Stick forward, no angle of attack, no danger of further blade flap.

Perfect safe landing.

Logical?

Try it and lets fly safer!

Len

[Condor]

Thanks Gyronaut.

These are all things we should know and repeat in the middle of the night.

However it is good to read it again.

[mak]

Len

I agree that a high speed blade flap is the most probable cause. Only thing that puzzles me is that the rudder and vertical stabilizer looks undamaged. Almost all blade flaps, according to me, chop the vertical stabilizer and rudder off before hitting the ground, or am I wrong? Can a flat rotor angle (as is the case with normal blade flap) prevent this.

[Learjet]

Len

I agree that a high speed blade flap is the most probable cause. Only thing that puzzles me is that the rudder and vertical stabilizer looks undamaged. Almost all blade flaps, according to me, chop the vertical stabilizer and rudder off before hitting the ground, or am I wrong? Can a flat rotor angle (as is the case with normal blade flap) prevent this.

Also noticed the vertical stab had escaped being chopped - this suggests that there was still sufficient rotor rpm to provide enough coning of the blades to clear the stab.
Blade flap could well have occurred - though it may not have been that severe. A contributing factor may be that the stick back to "brake" the forward roll spun up the rotors enough to inadvertently lift off and the pilot may have been caught completely off-guard - add some torque roll... BANG! rotor ground strike and over it went.

Whatever the case glad everyone was ok.

[saraf]

Training and Pilot error...............

I do not see Blade Flap happening here, nor does the aircraft show signs of blade flap. ( Tail not chopped)

Training , Training, Training, Training, Training.....................

[Gyronaut]

um, remember Gyroscopic precession? Where are the resultant forces going to impact? Don't forget Newtons laws. "opposite and equal reaction"

It is a simple fact that when an outside force is applied to a rotating body, the result of the outside force will occur approximately 90 degrees later in the plane of rotation.

Lets say the advancing blade changes angle of attack and flies (generates lift) violently at 3 o'clock. (counterclockwise rotating rotor of course). The advancing blade flaps up dead-ahead (Pushing the retreating blade down changing the apparent wind to that blade so that the retreating blade creates more lift but not as much as the advancing one causing disparity of lift. One blade flies more than the other, picks the gyro up and rolls it over. My logic says - If the apparent wind is dead ahead the tail may suffer otherwise it will roll-over sideways (to downwind).

Fluid dynamic/aeronautic experts can enlighten us perhaps?