Fatal - AutoGyro MTOSport D-MTMZ, near Hildesheim airfield, Germany

fara

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Here is one thing that should be very obvious to anyone paying a lick of attention.

Extruded blades are risky.

Rotor blades constructed with a spar and glued skins seem to be the safest type of construction available.

If you have the money to afford these expensive gyros, then spend another couple thousand dollars and replace your questionable extruded blades with a set of blades from Gyrotechic or sportcopter, then you will have peace of mind.

The only extruded rotors I have heard having serious issues are all copies of AirCopter rotors.
That is
AutoGyro rotor system
Trendak rotor system

Do you know any other extruded rotors generally used having these issues?
 

GyroRon

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The only extruded rotors I have heard having serious issues are all copies of AirCopter rotors.
That is
AutoGyro rotor system
Trendak rotor system

Do you know any other extruded rotors generally used having these issues?
No, I don't follow trends or compile data like UK steve, etc....

But extruded blades have been discussed on this forum for over a decade. Men I consider true experts like Chuck Beaty have explained why extruded blades are a poor choice.

You build a Euro style gyro in America... I don't understand why you wouldn't want to use american made blades on your american made gyro regardless of whether extruded blades are considered ok or not.
 

fara

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No, I don't follow trends or compile data like UK steve, etc....

But extruded blades have been discussed on this forum for over a decade. Men I consider true experts like Chuck Beaty have explained why extruded blades are a poor choice.

You build a Euro style gyro in America... I don't understand why you wouldn't want to use american made blades on your american made gyro regardless of whether extruded blades are considered ok or not.

Well men like Chuck Beaty also say that using stainless steel will work harden and crack in little time. Well, from what I know the only ones cracking engine mounts and frames are a couple of different models. They are made way too light and have fully penetrated welds that were suffering from sugaring/cauliflowering. We fixed a couple right at our shop. We saw their welding on the back side because in front its all very pretty. That is not the fault of stainless steel. That's not welding SS properly on a fully penetrated weld. It is true, that sugaring is not an issue on a 4130 Chromoly frame but it can have other issues like normalizing depending on material thickness and welding techniques. Everything requires a production process that is executed properly in any aircraft in any material.

My choice for gyroplane rotors are/were what in America?

Dragon Wings - Meaning doing business with Ernie. His quality control and precision left a bit to be desired I am sorry to say. Plus his rotors are 7 inches wide while what I would like is 8 to 8.5 inches wide. He did make high inertia rotor blades a few years ago and when Greg flew them, he said we need to test them more before making a decision but Ernie wanted them back within the same day. I could not in good conscience do less than a day's worth of testing on a new model rotor blades and offer them as standard on production gyroplane. But that seemed to be what Ernie was willing to do. A blessing in disguise because a couple of years later Ernie sold the business to a fraudster and then the business is shutdown for good and no blades to be had for anyone.

Sport Copter - I tried and basically got told I can buy their rotors at retail price and when I asked about being an OEM basically got told straight out quite emphatically I might add that we don't care. Plus the fact that they are competitors not just blade manufacturers.

Skywheels - Tried those and they were divergent and dangerous and found out there are big personality issues there as well when negative feedback was provided constructively to improve or solve the divergent behavior. Can't do business with people like that. May be its the gyroplane industry from the past in the US but I am used to much more level headed and professional outfits in trikes and airplanes. I am not about to lower my requirements. Since then Skywheels has been sold to new people but I do not know how technical they are and if they know of these problems. And new people also mean no historical knowledge of the design and production system so they will learn as they go. That puts them in the new rotor production in my book. Its not like Skywheels was such a technical outfit that every process was documented to a T and all tribal knowledge was captured for even such a critical part as rotors

We tried GyroTech composite rotors (Poland) as well. Side by side with Averso on the same day on same machine with same weight. Obviously we don't use them so you can draw your own conclusions from that.

Averso has 17 years of history and I could not find a single cracking or in-flight failure in my research. They have produced this specific model of blades since 2004 and over 1400 are out there. The data supports that while AutoGyro and AirCopter rotors (basically copies of each other really) had already had cracking issues even 10 years ago, Averso did not and has not. Averso has a steel rod alloy all the way through the blade submerged in a non-conductive layer of glue. Its not just the extrusion. Dealings with Averso have always been professional, product always consistent, dialog always constructive and reasonable and they take responsibility when they screw up which is hardly ever. Whatever they do seems to work and is proven in the field.

In training Greg has had over 800 hours on single Averso rotors without an issue. I have a trainer with 550 hours of hard core training on it (350+ just this year). That's a lot of cycles of taking off and landing (and not always nicely with students). A normal owner would not do in 2000 hours what we do in training in 500. Basically on average 8 landings and takeoffs an hour on each training hour is a good estimate.

As much as I would love to use US manufactured rotor blades that are well proven in the field by years of experience, I would also like reasonable level headed professional people who have high standards personally and tight tolerances for one of the most critical parts of the aircraft, to deal with and that combination does not exist in my limited exposure in the US blade suppliers for gyroplanes yet. I could get into manufacturing our own blades but I have other things I can work on like developing a side by side gyroplane and working on an Agro version of AR-1 for which we have funding and potential customers.
 
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GeneralPatton

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Hi there, Phillip here,I got a little concerned reading these posts,I have a Calidus 2017,914 turbo, certified, 350 happy hours trouble free,just pulled the blades, did a crack inspection c/w SB Autogyro for root cracking , longitudinal cracks, and bolt hole radial cracks, result, no defects noted,no galling, no corrosion, no hole
deformation. I fly this machine every day and it is a honey.I have had my share of hard landings, my take on all the words shed by people that don’t like extrusions style rotors is this in Vance’s linear style:

IMHO Autogyro has a well designed product and has supported me and this aircraft in a responsible fashion.

The change from RS1 to RS2 is a response to real world engineering . My system is RS2.

i own and operate a 269B Hughes heli, I cant tell you here of the dozens of AD on this aircraft to keep it airworthy.

The testing that has been done is in accord with ASTM and ISO 9000 standards.
AG has done its due delligence more than any other manufacturer that I can see.

How many other gyroplanes are primary certified today and being manufactured?
Have any maintained RS2 rotor systems failed in flight?
My qualifications:
LSAM&T FAA
Autogyro Certified Line And Heavy Maintenance Tech
ROTAX Factory Trained Tech

Of all the postings of well meaning people, how many own, operate, maintain,
and fly an AG product ?

I am now going to put the blades back on the Calidus, and sleep well tonight.

Mike Busch is one of the primere A&P in The GA world of engines and airframes.
Read his books , ENGINES and MANIFESTO, and learn volumnes.

listen and heed Vance, his is the voice of experience, which beats theory any day.

If any one needs assistance with their gyro or LSA, Or Rotax 9 series engines,
I am in central NC at NC25, give me a call, 980 332 0518, I am mobile to other locations. Phillip
 

Philbennett

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To the point above. Natural for the questions however, especially since the official reports take a very long time to be published and unless you happen to know someone you are left simply not knowing. UK Cavalon fatal in Scotland for example saw the entire rotor detach, although the report is likely to conclude through overloading but of course read about a rotor detaching and not difficult to understand a concern. So to this German accident - what doesn't sit well is the wording in the German authority statement on rotors and maintenance when the aircraft is at the home airfield of the manufacturer and the instructor as experienced as he is. Either that statement from the authorities doesn't translate well, is badly worded, is unnecessary or very troubling.
 

GyroRon

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Well men like Chuck Beaty also say that using stainless steel will work harden and crack in little time. Well, from what I know the only ones cracking engine mounts and frames are a couple of different models. They are made way too light and have fully penetrated welds that were suffering from sugaring/cauliflowering. We fixed a couple right at our shop. We saw their welding on the back side because in front its all very pretty. That is not the fault of stainless steel. That's not welding SS properly on a fully penetrated weld. It is true, that sugaring is not an issue on a 4130 Chromoly frame but it can have other issues like normalizing depending on material thickness and welding techniques. Everything requires a production process that is executed properly in any aircraft in any material.

My choice for gyroplane rotors are/were what in America?

Dragon Wings - Meaning doing business with Ernie. His quality control and precision left a bit to be desired I am sorry to say. Plus his rotors are 7 inches wide while what I would like is 8 to 8.5 inches wide. He did make high inertia rotor blades a few years ago and when Greg flew them, he said we need to test them more before making a decision but Ernie wanted them back within the same day. I could not in good conscience do less than a day's worth of testing on a new model rotor blades and offer them as standard on production gyroplane. But that seemed to be what Ernie was willing to do. A blessing in disguise because a couple of years later Ernie sold the business to a fraudster and then the business is shutdown for good and no blades to be had for anyone.

Sport Copter - I tried and basically got told I can buy their rotors at retail price and when I asked about being an OEM basically got told straight out quite emphatically I might add that we don't care. Plus the fact that they are competitors not just blade manufacturers.

Skywheels - Tried those and they were divergent and dangerous and found out there are big personality issues there as well when negative feedback was provided constructively to improve or solve the divergent behavior. Can't do business with people like that. May be its the gyroplane industry from the past in the US but I am used to much more level headed and professional outfits in trikes and airplanes. I am not about to lower my requirements. Since then Skywheels has been sold to new people but I do not know how technical they are and if they know of these problems. And new people also mean no historical knowledge of the design and production system so they will learn as they go. That puts them in the new rotor production in my book. Its not like Skywheels was such a technical outfit that every process was documented to a T and all tribal knowledge was captured for even such a critical part as rotors

We tried GyroTech composite rotors (Poland) as well. Side by side with Averso on the same day on same machine with same weight. Obviously we don't use them so you can draw your own conclusions from that.

Averso has 17 years of history and I could not find a single cracking or in-flight failure in my research. They have produced this specific model of blades since 2004 and over 1400 are out there. The data supports that while AutoGyro and AirCopter rotors (basically copies of each other really) had already had cracking issues even 10 years ago, Averso did not and has not. Averso has a steel rod alloy all the way through the blade submerged in a non-conductive layer of glue. Its not just the extrusion. Dealings with Averso have always been professional, product always consistent, dialog always constructive and reasonable and they take responsibility when they screw up which is hardly ever. Whatever they do seems to work and is proven in the field.

In training Greg has had over 800 hours on single Averso rotors without an issue. I have a trainer with 550 hours of hard core training on it (350+ just this year). That's a lot of cycles of taking off and landing (and not always nicely with students). A normal owner would not do in 2000 hours what we do in training in 500. Basically on average 8 landings and takeoffs an hour on each training hour is a good estimate.

As much as I would love to use US manufactured rotor blades that are well proven in the field by years of experience, I would also like reasonable level headed professional people who have high standards personally and tight tolerances for one of the most critical parts of the aircraft, to deal with and that combination does not exist in my limited exposure in the US blade suppliers for gyroplanes yet. I could get into manufacturing our own blades but I have other things I can work on like developing a side by side gyroplane and working on an Agro version of AR-1 for which we have funding and potential customers.

I will agree, that dealing with Ernie would have been potentially a pain in the butt. As much as I like him and his products, his customer service skills were very lacking.

Sportcopter had no issues becoming the OEM blade supplier for the Sparrowhawk line of gyros. Not sure how they could work that out and you couldn't.

GyroTechnic that I refer to, is Denis' company that makes the Razor blades. I highly doubt you would find anything to fault with his professionalism or his product.
 

fara

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I will agree, that dealing with Ernie would have been potentially a pain in the butt. As much as I like him and his products, his customer service skills were very lacking.

Sportcopter had no issues becoming the OEM blade supplier for the Sparrowhawk line of gyros. Not sure how they could work that out and you couldn't.

GyroTechnic that I refer to, is Denis' company that makes the Razor blades. I highly doubt you would find anything to fault with his professionalism or his product.

At the end of the day we will be claiming ASTM compliance on our gyroplane in 2023 as soon as MOSAIC NPRM passes and becomes law. The QA/Production standard in ASTM (which is cross-cutting not specific to gyroplanes) requires engineering drawings that are controlled by the manufacturer even if the rotors are manufactured by a dedicated supplier or sub-contractor. In a PO the manufacturer refers to a part number and specifies compliance to all the associated special process definitions and engineering drawings that go into making that specific part number. When a sub-contractor acknowledges that PO, he/she is on the hook for complying with all the associated drawings and processes. Also we would be responsible for the QA and tolerances on the blades not the supplier. If something is found wrong with the blades, the responsibility of that is on us not the supplier or sub-contractor. So there has to be a contract between us that allows us to hold them to the engineering drawings and to the tolerances and in process inspection sheets for QC that would become part of each gyroplane's manufacturing compliance record for the life of the aircraft. Also suppliers of all structural components need to be audited by the manufacturer once a year for their production system compliance. The only way out of the yearly manufacturer audit is AS9001 or at least ISO2000 type production system audit by authorized auditors that can be accepted by the manufacturer in lieu of their own audit. Furthermore, sub-contractors have to be open to allowing FAA/NTSB to come to their factories and audit them anytime with some reasonable notice.

I doubt Ernie would ever deal with all that but these are the norms in aviation supply chains.

ASTM compliance for production is at the same level as a Part 23 Production Certificate holder for a light airplane (e.g. Liberty Aerospace in Florida and the like). The only difference is you are claiming self-compliance instead of being constantly monitored by the FAA MIDO (Manufacturer Inspection District Office). But that does not mean they can't come in any time and check on you. They can and they do from time to time, specially if the fleet has accidents. I know my previous company in trikes was audited fully by FAA audit team after a couple of fatal accidents in Hawaii. Its the same audit team member pool who audit Boeing.

Sportcopter - well may be it was a bad day for some employee the day I tried to talk to them. This was in late 2015/early 2016. We'll see what happens

Gyrotechnic does not have the sizes of rotors we need. They are geared towards single seat machines. Neither chord is 8 to 8.5 inches nor the span is 28 feet or higher. And they are quite new rotors yet. May be a year or so more.

Anyway, this is a tangent from the subject matter. The DULV bulletin was badly worded and confusing at best. We'll have to wait for basic info like how old and hours on that machine and where the debris field was.
 
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fara

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So I am just going to guess that the corrosion picture in the DULV notice was then indeed the blades from fatal accident in Germany.
That is quite amazing to me that in 2 years those blades contacting a zinc plated class 8.8 bolt corroded that badly.

As a side note, when we assemble Averso rotor blades here, we always put a tiny thin layer of anti-seize on the bolt shank, being careful not to get it on the threads (due to dry thread torque values being used). We are in Florida which is fairly humid and somewhat salty air and I have not encountered corrosion that looks anywhere near that. In fact not even close. I do not know if its that thin layer of anti-seize keeping the battery from activating and causing corrosion or not.

I do wish that Averso would use AN hardware instead of metric DIN standard hardware because of the Cadmium plating on them is much better in causing less valance differential and less corrosion with contact with Aluminum and also Cadmium has a different lubricity and can achieve the same clamping force at a lower torque spec.

It seems to me that they are determining that corrosion played the most significant role in this fatal accident. One of the blades was simply not at the scene. It seems like it had an accelerated fatigue cycle due to corrosion and cracked off. Mind you that this is only inferred by me looking at information available. Certainly the mandatory bulletin does not say that or anything about the German accident aircraft
 

DavePA11

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Wow, surprised anyone would fly with any bolts that had corrosion like that. Actually, after seeing many ultralights I guess I am not surprised…
 

fara

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I may have missed it, but where is it confirmed that the photo of the corrosion was actually of the aircraft we're discussing?

I didn't confirm anything. As I wrote I am guessing given this mandatory bulletin, that the DULV bulletin did contain the picture of the accident aircraft blade in it. There would be no reason for this mandatory bulletin in the UK if they were not concerned about extreme corrosion in the blade where it contacts the steel bolts.

I have to say I am surprised at that corrosion for a relatively newer gyroplane. I have seen zinc plated bolts in Aluminum tubes in trike wings all the time and I have never seen corrosion to that extent. It seemed like someone literally did a salt spray on those bolts and then no one ever cared to wash them with fresh water and dry them out and may be put some corrosionX on them.
 
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Philbennett

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The SB is incredible on so many levels. As far as it relates to the fatal accident in Germany now it raises the question mark around not just the serviceability of the accident aircraft as far as simply having items checked at the required interval but now one wonders the materiality of the checks in any event and the wider thinking around the longer term integrity of the rotor.

As I read the prior [to this SB] service worksheet the biggest change is a reduction in time for the inspections and a specific much more stringent checking once the rotor has gone beyond 1500hrs - where the focus then seems to be upon hours not time in service. That new focus upon hours rather than time in service is odd [unless there is a new worry] because if the rotor is being inspected and bolts replaced along the way I can't really see why a rotor that has gone beyond 1500hrs suddenly needs greater checking because one assumes the degradation of bolts as far as corrosion is concerned has greater alignment to time in service than hours flown?

The narrative to the SB is given as

Considerable worldwide service experience now exists for the AutoGyro aircraft fleet, based on hours in service and age in service, particularly with respect to corrosion. Experience gained has shown that continued long-term safe operation will be enhanced by a change to the rotorsystem inspection requirements.
Although the accident in Germany does seem far too coincident and it would be interesting to know at what point on the scale of usage that aircraft was.

Finally the level of attention now is going to be a painful end to 2021 for owners because not only is getting this work done going to be challenging if parts are needed then it likely ends the year of flying for many. It also makes flying higher hour aircraft difficult for instructors [as 100hr checks likely means 4x yearly inspections], expensive and when the reuse of Nyloc's are not forbidden outright I predict finger trouble / bad practice ahead.

In the UK this is not good at all because with only 2 manufacturers to choose from if one wobbles then it does not bode well for the longer term future of gyroplanes in the country. To finish on a positive - kudos to the BRA for the bulletin. I read that they are re-motivated to get back involved with gyroplane regulation and formulation of future policy by better [read "some"] representation with authorities. Good for them - it needs a strong, independent and non-personal voice to speak up for the community rather than it being left to the individual.
 

Vance

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I didn't confirm anything. As I wrote I am guessing given this mandatory bulletin, that the DULV bulletin did contain the picture of the accident aircraft blade in it. There would be no reason for this mandatory bulletin in the UK if they were not concerned about extreme corrosion in the blade where it contacts the steel bolts.

I have to say I am surprised at that corrosion for a relatively newer gyroplane. I have seen zinc plated bolts in Aluminum tubes in trike wings all the time and I have never seen corrosion to that extent. It seemed like someone literally did a salt spray on those bolts and then no one ever cared to wash them with fresh water and dry them out and may be put some corrosionX on them.
Hi Abid.

Thanks for writing back. Yes, I know you couldn't confirm it which was why I asked the question. The photo almost reminds me of stress test and material studies a company I used to work for often did, subjecting critical parts to various salt water sprays for extended times, etc., in the hope of identifying problems and determining longevity. I want to believe this photo is NOT of the doomed gyro, because if it is then I would be extremely paranoid about climbing into this style plane, which I'm planning to do this spring for training.
 

rcflier

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DULV state clearly, that the pictures are shown as examples only. Come on, that has been established! Some of us can read German.
But it could be a hint, that it threw a blade - it seems like the accident was that violent.
The prudent thing to do is to make sure, it won't happen to other gyros. And that's probably what's being done now.

But the rotors have to be taken apart and inspected for cracks at intervals already. The one-bolt-at-a-time -
might it be the bolts in the hub??

Erik
 

JETLAG03

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The SB is incredible on so many levels. As far as it relates to the fatal accident in Germany now it raises the question mark around not just the serviceability of the accident aircraft as far as simply having items checked at the required interval but now one wonders the materiality of the checks in any event and the wider thinking around the longer term integrity of the rotor.

As I read the prior [to this SB] service worksheet the biggest change is a reduction in time for the inspections and a specific much more stringent checking once the rotor has gone beyond 1500hrs - where the focus then seems to be upon hours not time in service. That new focus upon hours rather than time in service is odd [unless there is a new worry] because if the rotor is being inspected and bolts replaced along the way I can't really see why a rotor that has gone beyond 1500hrs suddenly needs greater checking because one assumes the degradation of bolts as far as corrosion is concerned has greater alignment to time in service than hours flown?

The narrative to the SB is given as


Although the accident in Germany does seem far too coincident and it would be interesting to know at what point on the scale of usage that aircraft was.

Finally the level of attention now is going to be a painful end to 2021 for owners because not only is getting this work done going to be challenging if parts are needed then it likely ends the year of flying for many. It also makes flying higher hour aircraft difficult for instructors [as 100hr checks likely means 4x yearly inspections], expensive and when the reuse of Nyloc's are not forbidden outright I predict finger trouble / bad practice ahead.

In the UK this is not good at all because with only 2 manufacturers to choose from if one wobbles then it does not bode well for the longer term future of gyroplanes in the country. To finish on a positive - kudos to the BRA for the bulletin. I read that they are re-motivated to get back involved with gyroplane regulation and formulation of future policy by better [read "some"] representation with authorities. Good for them - it needs a strong, independent and non-personal voice to speak up for the community rather than it being left to the individual.
Hi Phil.

Astounding, folks re-use nyloc nuts? I do not even re-use nyloc nuts on cars and motorbikes. Some lifes must have a much lower value than others.

phil
 

fara

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Hi Phil.

Astounding, folks re-use nyloc nuts? I do not even re-use nyloc nuts on cars and motorbikes. Some lifes must have a much lower value than others.

phil

Hi Phil:
This should not be so surprising. You have flexwing (trike) hours. If you read maintenance manuals for say Airborne trikes, you will see they allow re-use of nylock nuts if for instance the nylon engagement material can produce locking torque within specifications. The never reuse a nylock nut is an advise if you don't know what you are doing kind of person

From FAA AC43.13-1B
"f. Fiber or nylon locknuts are constructed with an unthreaded fiber or nylon locking insert held securely in place. The fiber or nylon insert provides the locking action because it has a smaller diameter than the nut. Fiber or nylon self-locking nuts are not installed in areas where temperatures exceed 250 °F. After the nut has been tightened, make sure the bolt or stud has at least one thread showing past the nut. DO NOT reuse a fiber or nylon locknut, if the nut cannot meet the minimum prevailing torque values. (See table 7-2.)"

If you are not sure what is being talked about here and your manufacturer does not tell you anything, for sure change the nut to a new one but if you have guidance and experience, you certainly can reuse nylock nuts safely on the same bolt/threads it came off of (that's important) several times. In coastal regions, I'd drop a small drop of 242 loctite of equivalent on the threads of metal nuts or old my lick nuts for locking and preventing rust. Specifications for aerospace fasteners like NASM require that running torque values be held by the nuts after a number of cycles of assembly so if you are using AN/MS hardware or NAS hardware, the reuse is right in the spec for design
 
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rcflier

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I read (or was told), Loctite is not good for Nyloc nuts - use either Loctite or use Nyloc nuts.

Was it wrong advice?
 
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