Fatal - AutoGyro MTOSport D-MTMZ, near Hildesheim airfield, Germany 21 JUL 2021

[PJB]

Downloadable report on Cranfield University report on AutoGyro blades

RS1 was 6005 material. Cranfield's view on the material is:-

It is unlikely that there will be significant differences in the crack growth
characteristics of 6061 and 6005 as they are of similar strength and similar aluminium
alloy series.

No idea on the cause but the above report highlights the number of "cycles" the blades go through, which in a training aircraft are likely to be higher than an aircraft used by pilot / owner who is likely to do less air-ground-air cycles.

 

[Greg Vos]

Blade section attached to aircraft

Is this a pic from the accident or have you listed it as an example?

 

[Kevin_Richey]

I have to admit perplexity w/ the absence of gyroplane accident reporting coming from our forum member, Steven May ("Steve_UK"), of England, who always has been first @ reporting of any incident or accident worldwide.

 

[Abid]

I pointed out that 6063 was used years ago when we first started to hear of extruded aluminum rotors. I have no idea what Autogyro of Germany uses in their construction/extruded process.

What # of aluminum are Averso rotorblades, Fara?
The only failures (fatalities) I have heard of from carbon fiber construction have been of the balance rod of one rotorblade being flung out in flight (w/ horrible results to the pilots & passengers & their families), and not from breaking apart in flight.

But, I'm not on the insider knowledge track of rotorblade failures worldwide, as the gyroplane & rotorblade manufacturers are...as well as those w/ access to photos showing all of this not shown to the public.

I do know that this thread on our forum from a couple of yrs. ago delved extensively into crystallined aluminum (likely from being work-hardened) & rotorblades breaking off @ the point where the last outboard bolt held the rotors to the hub bar:

https://www.rotaryforum.com/threads/another-look-at-the-autogyro-mtosport-crash-of-11-september-2016-in-germany-d-mdoz.1143796/

If one reads that thread casting away the personality clashes between CFIs & other gyro flyers, it is chilling to compare previous rotorblade departures from the hub bar, whether catastrophic collisions w/ Mother Earth, or merely mild tip-overs while taxiing or slightly airborne impacts in ground effect.

I haven't heard in the 30+ years I've been involved in gyroplanes of ANY Skywheels, or Dragon Wings nor Sport Rotors having the hub bars or rotorblades depart in flight from material failure. I would expect that Denis Shoemaker's new aluminum Razor Blades to have the same robustness, since they appear to utilize the same material & construction process as DWs & SRs.

ELA composite rotors in Poland and I believe one in Spain have had fatal consequences.

I know of cracks on 2 ELA composite rotor systems right here in Florida. One right around the same place (right after the last clamping bolt).

Skywheel blades have been in accidents decade plus ago and in NTSB reports I remember reading the view on their construction.
Anyway, AutoGyro hub bar to blade clamping mechanism is not the best in my opinion. They have seen clamping create problems before in 2011 as we all know and RS1 rotors were retired at 700 hours generally because of that and they designed RS2 which they produced themselves. The clamping mechanism although better than RS1 still has only a couple of points of actual contact on the blade contour and does not spread out the load evenly over a large area. The alpha on that point then is increased potentially reducing fatigue life of the blade in that area by design. Why they do it that way is beyond me. May be they know something I don't but no one else in any blades does it quite that way and in no way this means that this is what caused this accident unless the picture posted above by SARAF is of a blade from this accident not just an example from somewhere.
I still don't know if the engine came off in this accident in flight or the blade came off or both came off. If engine came off and hit the blade, then blade coming off isn't really the main issue. We just need to wait to get factual data. If engine was found 100's of feet away from the accident site, its fairly obvious what happened.

 

[Steve_UK]

I have to admit perplexity w/ the absence of gyroplane accident reporting coming from our forum member, Steven May ("Steve_UK"), of England, who always has been first @ reporting of any incident or accident worldwide.

Wow. Tyro was ahead of me on this one. FAA ASIAS did produce a new one today for a Tango 2. Fatal in Australia a few days ago too. Sadly no shortage of incidents/accidents.

 

[cmb]

Posting this for Mike G. as he currently doesn't have access to his laptop.

 

[Abid]

Posting this for Mike G. as he currently doesn't have access to his laptop.

View attachment 1153019

Guten Abend
Die meisten von uns sprechen in den USA kein Deutsch. Übersetzung bitte

 

[DavePA11]

So what did it say?

 

[knussear]

Here is what google translate says it says

After the accident with a gyroplane on July 21st, 2021 in Hildesheim, the accident device a questionable maintenance condition and a contradicting one as a result of the accident investigation Operating time management established.

These findings determine the airworthiness of the device involved in the accident urgently in question
Recommendation: Every operator or pilot in charge should immediately receive the Check the maintenance status of the affected gyroplane. Manufacturers give maintenance and Maintenance instructions in their maintenance manuals.
• Is the maintenance on the gyroplane on schedule according to this information? carried out and documented accordingly?
• Do these have to be made up immediately, if necessary?
• In case of doubt, the gyroplane has to be taken out of service until clarification become?
• Do you have to contact the manufacturer if you have any questions? We point out that the control of the maintenance work is not only the one shown here Rotor connections, but all prescribed maintenance work (the pictures are only shown as examples).
Deadlines: Before the next start, then according to the specifications (maintenance work / Operating hours / interval) of the maintenance manual.
Approval: This safety advisory is not an airworthiness instruction (AD) and is from Not to be approved by sample owners.
The DULV instructs here as a precaution in agreement with the Federal Office for Aircraft Accident Investigation (BFU) on possible safety deficiencies.

 

[DASBUR]

Helicopter rotors have to deal with huge power pulses. Apples and Oranges and really not relevant. And this accident I highly doubt has anything to do with extruded rotors. We have seen composite rotors throw apart and kill people as well on gyroplanes and it all depends on design and construction method of specific rotors.
This problem has happened before on AutoGyro rotors in 2011. They came out with rotor system 2 as a result and somehow set their life to 2400 hours when rotor system 1 had trouble at 700 hours. I asked Averso how can they set the time to 2400 hours. Averso's answer to me was if AutoGyro rotors can be set to 2400 hours, theirs would be to 3000 hours but they don't believe it is dealing with reality. Their clamping plate design is different and a bit strange in my opinion. It does not touch through the whole blade surface and creates a potential flexure point for the blade. Why? I never understood that. I am guessing this is rotor system 2 on this machine.

No the extruded rotors them self may be fine on a gyro but there attachment method in my opinion was an accident waiting to happen.

Doug

Just my uneducated opinion

 

[Martin W.]

From my armchair view ...

It could be a photo anomaly , shadows , dirt , or my imagination , but the portions (circled in red) look like older cracks as compared to the rest of the aluminium which looks more like a recent fresh break.

As a sidenote to aluminium extrusions .... here is the predominant issue : ... semi-molten aluminium is squeezed through a die (the die is very short in length) ... as the extrusion exits the die there are gaps between the segments of the die .... and if everything goes well those gaps close up and "join themselves" (weld themselves) back together .

The gaps are by the construction of the dies .... the various shapes of the die (round holes - rectangles - trailing edge) have to be joined together to hold themselves in place while the aluminium is forced over them.

In a perfect world the dies would be the full length of the blade , die segments would be joined together on the outside , but by the time it was done extruding the aluminium would have cooled and shrunk onto the die making blade removal impossible

 

[SARAF]

Is this a pic from the accident or have you listed it as an example?

No its the actual accident blade

 

[Resasi]

Would seem to make a case for periodic blade disassembly and inspection.

That bolt looks horrendous but does not actually seem to be the area that failed.

Could it however been the cause of the failure in that area by allowing flexing that would not have occurred had the bolt been replaced?

 

[Greg Vos]

Would seem to make a case for periodic blade disassembly and inspection.

That bolt looks horrendous but does not actually seem to be the area that failed.

Could it however been the cause of the failure in that area by allowing flexing that would not have occurred had the bolt been replaced?

With the older xenon gyro we have a SB from Trendak saying mandatory removal of the blades every 25 hours, it’s a pain in the ass I have in the last few months removed the blades 3 times and so far no evidence of cracks or mounting hole deformation.
The hub bar is of a different design & the blade pocket fits the blade profile like a glove with full contact

 

[Resasi]

Wow. Tyro was ahead of me on this one. FAA ASIAS did produce a new one today for a Tango 2. Fatal in Australia a few days ago too. Sadly no shortage of incidents/accidents.

Steve I do know that you were attacked as being a ghoul for bringing these to the attention of the Forum, but as sad and tragic as these events are, I believe that studying them serve a definite purpose in sometimes bringing vital findings to light, and acting as a necessary reminder on safety issues, vigilance, and good practice.

 

[wolfy]

With the older xenon gyro we have a SB from Trendak saying mandatory removal of the blades every 25 hours, it’s a pain in the ass I have in the last few months removed the blades 3 times and so far no evidence of cracks or mounting hole deformation.
The hub bar is of a different design & the blade pocket fits the blade profile like a glove with full contact

While it's probably a good idea to keep an eye on things, every 25hrs would sure be a pain. In the mustering game that comes around every 2 and a bit days .
Surely every 100 hrs would still be reasonable, every time the bolts go in and out they take a tiny bit of aluminium with them eventually hogging out the holes.

wolfy

 

[Greg Vos]

While it's probably a good idea to keep an eye on things, every 25hrs would sure be a pain. In the mustering game that comes around every 2 and a bit days .
Surely every 100 hrs would still be reasonable, every time the bolts go in and out they take a tiny bit of aluminium with them eventually hogging out the holes.

wolfy

Agree fully with you, and we also run risk of damage and “hanger rash” with assembly and disassemble work, I think in the case of the Xenon and Trendak they are covering themselves and sent that SB out after the crash in Poland wherein an instructor and student were killed, again if go back and look at the pics supplied the aircraft and blades did not look like in good condition.

in this horrific accident have we had any word on the chain of possible events? eg: did a prop blade come off that started the events, that caused the engine to come out that could have caused the blade to come off ( not that with the loss and weight of the missing engine) the aircraft would have been controllable

I would like to get an understanding of the events that lead up to this, considering the high profile of the instructor and the MT integrity often mentioned in the AG sales talks, this accident is odd and very scary

 

[SARAF]

I have to admit perplexity w/ the absence of gyroplane accident reporting coming from our forum member, Steven May ("Steve_UK"), of England, who always has been first @ reporting of any incident or accident worldwide.

its his fav manufacturer so his absence speaks volumes.. if this was a RAF he would have been all over it in an instance.....

 

[Greg Vos]

its his fav manufacturer so his absence speaks volumes.. if this was a RAF he would have been all over it in an instance.....

I do not think it’s his favourite gyro by a long shot…. That said there certainly is a bias among many low time pilots that Auto Gyro is the best…. While they are certainly the biggest in sales numbers they are ‘soft ‘ IMO

I am preparing for a lot of flack for that comment … normally only from pilots who have only flown the AG range and who have little exp with what’s out there

 

[Brian P]

That photo of the broken blade looks like it's been sat out in the weather for a few months in that state. The threads don't look like a nut has been recently removed. Sceptical that this is the actual part off the accident machine in question.