STILL LOOSING WINGS - another killed

[Thruster87]

There is a lot of talk about the "design mods".... if there are mods then quite clearly there is a problem with the wing of this AC......The inference "if it is operated within normal limits it is OK" is a totally unacceptable explanation for a number of AC that have suffered common catastrophic wing failures. The design and load limits should be tolerant of sudden inadvertent loads such as in gusts etc. Make no mistake in judgement this a serious issue and if I owned one it would be grounded pending inspection (assuming the probelm is known).

 

There is clearly a design failure of some form for so many to fail...it is perhaps believable that the "ultimate load" testing was either flawed or misrepresented in some way unless the failure is attributable to other factors such as fatigue that may have been a consequence of poor design in another area.

 

Of the ones that have failed so far, is there a common "known" causal factor .... if so can someone explain to all of us concerned pilots what it is... since there are "mods" the causal factor must be known. If it is "known" it can be rectified and should be as soon as possible to protect the reputation of what appears to be a excellent AC and the lives of the owners.

 

Surely if you fix the problem and promulgate the fix ... the problem is no more and the owners can breath easy.....

 

Hopefully the designer is being transparent about the problem after all he will have insurance for this ....won't he???

 

David

There is no smoking gun with with respect to why these accidents have occured.You can rip the wings off just about any aircraft if you DO NOT OPERATE within the NORMAL LIMITS.

 

 

[Yenn]

I remember reading about wing failures some time ago. The designer came up with a later model with a different name, because of the old models failures. It didn't stop the new model failing, but it did make some people think the problem was fixed.

 

 

[kaz3g]

From AvWebFlash today...

 

EAA Survey Finds Zodiac Kit Owners Aware Of Safety Issues

 

AVwebFlash Complete Issue

 

When the FAA issued a Special Airworthiness Information Bulletin in November that effectively grounded some Zodiac aircraft until they were modified, that bulletin did not apply to amateur-built airplanes, although at least one of the aircraft that had been involved in a fatal crash apparently involving aerodynamic flutter was amateur-built. This week, EAA published the results of a survey of Zenith 601 XL and 650 kit owners that aimed to gauge their awareness of the SAIB, their awareness of the service directive/safety alert issued by the manufacturer, and their intent to comply with both. The results, EAA said, showed that owners/builders are aware of these developments, and 84 percent of those who responded to the survey are planning to incorporate the safety directive into their project, with a large majority voluntarily grounding their aircraft until modifications are completed. These results show that the homebuilt community is proactive about safety and self-regulates when needed, EAA said. Marc Cook, editor of Kitplanes, said his experience conforms to EAA's results. "This survey aligns with the feedback we have received from Zodiac builders, who seem willing to put safety well ahead of the inconvenience of making the modifications," he told AVweb. "One builder we spoke with called the proposed changes 'a huge job,' but felt that they absolutely should be completed."

 

EAA said since the majority of respondents wanted more facts, it recommends releasing the testing data so all members of the 601 community can assess it for themselves. "The safety of the pilots, their passengers, and persons and property on the ground is dependent upon this information being made available," EAA said. "If and when that factual data is released, EAA will do its part to inform our members and the homebuilding community. Our technical counselors, numerous chapters, and the manufacturer can and should be utilized to educate the 601 XL community on the extensive and challenging modification." Click here for EAA's complete survey results and analysis.

 

 

[techie49]

I'm loathe to reply to this hysterical thread but as some of the comments are so ill-informed and appear to be from 'armchair experts', I can't resist. I'm one of the many builders of the Zodiac 601XL who is patiently awaiting delivery of the modification kit to complete work on my aircraft. The cost of the mod kit is insignificant compared to the benefits it will provide when correctly installed. As has already been stated (and ignored) there is no clearly defined reason for the crashes that have sporadically taken place. There are hundreds of 601's flying quite happily with hundreds of hours on them. Have a look, if you want a morbid thrill, at the ATSB, et al, reports of accidents. You'll find an awful lot more commercial aircraft falling out of the sky than homebuilts. No one is trying to get you to fly or build a 601XL so what's the problem. If post-mod we still have unexplained accidents, then by all means postulate your 'expert' theories. I'd still rather be flying a self-built 601XL, confident in my careful construction and maintenance, than in a 30yr old C150 with potentially lethal hidden corrosion and a largely unknown history of use and abuse. It's blindingly obvious that homebuilt aircraft carry a risk. If the risk is unacceptable, stay in your armchair.

 

Paul Toone

 

 

[Spin]

I respect your viewpoint Paul, however the issue lies with the 601XL structural failures which appear to be several times more frequent than those suffered by the rest of the fleet. Unfortunately the designer has not helped the situation by firstly insisting that there is no problem and then apparently grudgingly coming up with a fix after the FAA started making noises:question:

 

I have flown an older 601 and liked it well enough (except for the wing skin acting as an aileron hinge!), but I'll be honest and say that until the fleet is modified and there are no more unexplained cases of wings folding, I will not be flying one.

 

 

[ianrat]

I agree with Paul. I am also building a 601XL. I researched the 601XL for a number of years before purchasing a kit. I was and still am very happy with the aircraft the way it is.

 

 

As Paul and others have stated NO one in the world has come up with a definite reason for the failure of the aircraft. There are a lot of people ready to give their thoughts on what has happened but there is no definite cause. No one can say for certain that the aircraft were not subjected to missus or neglect (Some people have stated this) prior to or at the time of the accident or there is in fact a structural defect with the aircraft. As these are only rumors I personally cannot and will not confirm or disregard them as fact.

 

 

There is a brand of commercial airliner in use that has caused more deaths and has had more near crashes than the 601XL but they are still in the air.

 

 

As for the designer not helping may be the reason for this is they have confidence in the design. There demonstrator has over 1000 hours on it with no signs of stress when they pulled it down to do the mods. May be the designer has just decided to over design it to buggery to shut up the critics out there.

 

 

It is my belief that all of the factory build 601XL have been grounded and all other owner build experimental aircraft have been asked not to fly until they have considered the mods the original post to this thread should be answered by this. I am not aware of any 601XL being flown in Australia at the moment without the mods.

 

I have spoken in person to both Michael and Sebastian Heinz and I believe they are all working to finally put the issue to rest.

 

As Paul has stated if there are more failures after the mods have been completed then you can say you told us so.

 

Ianrat

 

601XL Brisbane Australia

 

 

[nong]

Hullo fellas

 

I started this thread to express an opinion that maybe "no passengers" until resolved might be a good idea.

 

Its great to know that the designers sons (?) say that they are "on the job" or something similar. "they would say that, wouldnt they" comes to mind.

 

But hey its fun to speculate....after all Mr Heintz has, as I understand it, speculated that there is no problem. He is obviously a god.....and does seem to have picked up a good few deciples. Therefore, he is obviously right. !

 

As a relative lowlife I can but review the evidence and come out with what I reckon.

 

I judge these accidents to be the result of an airframe that is likely understrength for its operating limits ( weight/speeds ) combined with a pitch control system that needs redesign in relation to its human interface characteristics.

 

In other words I suspect that the pitch control system, as is, makes it too easy to load up the structure.

 

Stiffening the wings is surely good. Lets see if they go the full job and revise the pitch system and longitudinal characteristics next?

 

 

[ianrat]

Nong you humble yourself to much, indeed you are not just a lowlife as you have stated you must be higher than the gods.

 

In your (God like state) you have come up with the smoking gun that no other expert or agency around the world can find. You have judged the airframe to be under strength and suspect the pitch control of the aircraft. I do hope that your training and experience as an expert aeronautical engineer has led to your findings, or are you just another arm chair expert.

 

As I have stated in my prior post before purchasing my kit I investigated the CH601XL at length, this included talking to a lot of people in the industry including aeronautical engineers and they could not see any problem that stood out (not to say that there is none) but at least I have tried to the best of my ability to have a good look. I do hope that you have also done some at length investigating to back up your claims.

 

If you have followed the evolution of the 601XL in recent times the issue of the pitch control has been address. The designers have already put out a modification to the downward and upwards limits of the elevator.

 

As to answer your original post I am unaware of any 601XL that are flying here in Australia. Everyone that I know of are performing the mods before flight so there should not be any one carrying passengers.

 

As you may have pickup up from the tone of my reply I am a bit off when someone just tries to shoot down a design just because they can. Most of the owners around the world that have build and flown the 601XL have put a lot of money and time and effort into their aircraft. We would like to see the name cleared in the future as much as everyone else. This has already occurred with other aircraft that have had to undergo modification for structural failings and these days they again have a very good reputation in the industry.

 

If everyone is just putting on the aircraft this will never happen.

 

I am not saying that the mods will fix everything my crystal ball is still a little fogy on that one, (I am not an arm chair expert so I cannot say for sure) but I will put some trust into the designers and the other experts that it will.

 

So if you do not have a stake in the aircraft then please let the ones that do get on with job of getting them back in the air and get the name back. This will never happen while we are beating it down to death. If they fail after that then we will be the first to find out.

 

Ianrat

 

CH601XL

 

Brisbane Australia.

 

 

[ianrat]

BlackRod just a note the problem is with the CH601XL and the CH650 and not Zenith as a whole.

 

Zenith also makes other models that are not affected.

 

 

Ianrat

 

CH601XL

 

Brisbane Australia.

 

 

[Yenn]

Have you thought that maybe it doesn't solve the problem to increase the strength of the plane, but the failures may be due to another cause such as flutter. It is known that flutter can occur to strong airframes and other weaker designs will not have the problem. I don't know what the Zenith problem is but I do know that adding strength can be counter productive.

 

 

[winsor68]

I thought the only problem that could be found with design was with flutter due to slack control lines in some of the aircraft... a relatively minor fix, and one that would tear the wing off any aircraft. The Skyfox has lost its fair share of wings too but is still held in regard.

 

 

[ianrat]

It is my understanding that the issue of flutter was address by2 independent test performed late last year. There was no evidence of flutter in a correctly set up aircraft over the entire flight envelope.

 

The designers have put out a notice that the control cables must be set and maintained at the correct specifications.

 

In some of the reports it has been stated that flutter was evident but they also state that this could have happened after the wind started to break up.

 

 

Ianrat

 

CH601XL

 

Brisbane Australia

 

 

 

[winsor68]

I have always assumed that the aircraft, while being flown at or near Vne in rough conditions, experienced flutter- and that the knowledge to keep a closer eye on the control cables was not available or was not followed by the operators of the aircraft... Have there been eyewitness reports of the wing just folding on an aircraft? I seem to remember earwitnesses heard the distintive sound of flutter?

 

 

[Guest Maj Millard]

Quote: "If everyone is just putting on the aircraft this will never happen."

 

Ianrat

 

CH601XL

 

Brisbane Australia.

 

Ian, I don't think any of us are 'just putting on the aircraft' . We are responding to several serious structural failures, resulting in several deaths, that have occured with this aircraft type recently. Rather than you'r 'holyier than thou' tone, I would suggest you instead show some thanks to us, for even showing an interest in trying to solve what is really 'your' problem. There are plenty of people out there who are way beyond being, as you state, "armchair experts" and you need to listen to suggestions as they are offered................

 

 

[dazza 38]

HI David, i remember a aerobatic Grob, sorry cant remember the model number, but it crashed and killed the occupants, it crashed doing aero's. This was from flight safety magazine Years ago, it sustained control flutter, after leaving the paint shop. Dont quote me on this but from memory i think the ailerons were not re-balanced (mass balanced) after re-paint, it might have been elevators(but i doubt that).

 

 

[winsor68]

In my opinion... I recall seeing a lot of these sort of crashes with experimental/ultralight aircraft... I.e. flutter is the final culprit...That is what you get with simplified certification... It is not to say that the airframes are dangerous... all airframes have there limits.

 

 

[ianrat]

Maj. Millard I do not believe that I am Holyer than Thou just there has been a lot said on this thread regarding the lack of action on the designers part and that some members have come straight out and said what is wrong with the aircraft.

 

I believe the designer has been very active trying to find a solution with Flutter test and new Static load test as well being carried out by independent specialists. They have been working closely with all of the countries that have the CH601XL and the 650.

 

I am also very aware that there has been about seven plans go down due to an in flight structural breakup.

 

As I have also stated none of the experts around the world including the NTSB can say for certain what caused the actual breakups. So how can we say that XXX is the cause?

 

If someone has any ideas on the cause of the breakups (and I do appreciate the concerns and knowledge of others) they would be better to contact the designer direct and discuss it with them instead of just putting out here were it is just pushed back and forth.

 

The designer has come up with the list of modifications that are suggested to be completed on all experimental aircraft and mandatory on the factory built aircraft before we take flight again.

 

There was a lot of heated debate on a few of the sites in the USA until the mods were released by the designer and now the sites are all silent on the issue, they are just getting on with mods.

 

All I ask is to let the situation rest until the mods be done as per the designer’s specifications and we can get on with flying.

 

Please just let it rest.

 

 

Thank you

 

Ianrat

 

CH601XL

 

Brisbane Australia

 

 

[Captain]

All I ask is to let the situation rest until the mods be done as per the designer’s specifications and we can get on with flying.Please just let it rest.

 

I suspect that you are going to have trouble suppressing discussion on such a vital (and interesting) subject.

 

That is what forums are all about.

 

What I don't understand is that you make it sound like this was all resolved, done & dusted some time ago (someone described it as old-news) yet a pilot was killed in one, from what appears to be an in-flight breakup, just late last year.

 

When pilots are still being killed, you can hardly halt discussion.

 

 

[ianrat]

Captain you are correct. The Designer along with the NTSB and the FAA were already in discussion prior to the last accident.

 

All of the factory built aircraft were then grounded just after this failure and all experimental aircraft strongly recommended to have the modification that have been issued by the designers and AMD (Factory Build aircraft builder) undertaken. To say that this is done and dusted is partly true. The designer has released a list of modifications to the aircraft, all AMD units are grounded and the FAA and any similar body around the world will not register or reregister and CH601XL or 650 without the new modifications completed.

 

So as you can clearly see there is a lot happening in light of the in-flight failures.

 

The issue here is that the designer has done something about the issue and the rest of us (the owner builders) are trying to just get on with life and finish out aircraft.

 

My point is that all the discussion on this or any other site around the world at this stage will not change the outcome in the near future. It is up to the designer to tell us what should be modified.

 

I know that these aircraft are experimental and we can change what we want but I believe that if we do not stick to the designers mods we will have to prove to the authorities that the will be ok.

 

All other site around the world did have some very heated discussions prior to the mods being released and now have fallen silent on the issue.

 

As I have asked is that we are left alone to get on with what has been released by the designer and get them finished without further delay.

 

Thank you

 

Ianrat

 

CH601XL

 

Brisbane Australia

 

 

[Vorticity]

I can understand how sensitive builders of this type are when so much bad info is clouding the little real information that is available. The amount of time and moneywe all put into these homebuilts means that we become very committed to our design.

 

Realize though why there is so much interest in this matter. Structural failure would have to be the biggest fear of any pilot. I don't think anyone has been slandering the design. Fact is they have failed. The fact that experts dont know why and the designer is confident in the design doesn't do away with these in service failures.

 

I hope the mods prove succesfull and that they don't slow you down to much. I don't mind the zenith, seems a bit like a sonex that has been hitting the carbs hard over Christmas.

 

 

[chris]

I respect your viewpoint Paul, however the issue lies with the 601XL structural failures which appear to be several times more frequent than those suffered by the rest of the fleet. Unfortunately the designer has not helped the situation by firstly insisting that there is no problem and then apparently grudgingly coming up with a fix after the FAA started making noises:question:I have flown an older 601 and liked it well enough (except for the wing skin acting as an aileron hinge!), but I'll be honest and say that until the fleet is modified and there are no more unexplained cases of wings folding, I will not be flying one.

Spin

 

Sorry to bring FACTS back into this discussion but as you stated you flew in an OLDER 601, thats great.. Now the facts the older 601's have a very different and thicker wing design and structure than the XL..

 

For the others

 

who remembers the early RV's and the problems thay had..

 

Total cost for the upgrade as about $500 worth of metal. yes it will take about 80 hours to do the upgrade and will strengthen the wing.

 

Also have a read of the flutter testing report available, with correct cable tension it does not flutter, with slack / loose cables it does. Ok maintain correct cable tension..

 

Now back to building for those of us

 

that are living the dream not just dreaming the dream.

 

 

[Adrian Lewer]

Great and I might have just bought a 601 ? marvelous ?

 

 

[Spin]

Spin Sorry to bring FACTS back into this discussion but as you stated you flew in an OLDER 601, thats great.. Now the facts the older 601's have a very different and thicker wing design and structure than the XL..

For the others

 

who remembers the early RV's and the problems thay had..

 

Total cost for the upgrade as about $500 worth of metal. yes it will take about 80 hours to do the upgrade and will strengthen the wing.

 

Also have a read of the flutter testing report available, with correct cable tension it does not flutter, with slack / loose cables it does. Ok maintain correct cable tension..

 

Now back to building for those of us

 

that are living the dream not just dreaming the dream.

Just seen this one now, can I suggest a another read of my post without jumping to unwarranted conclusions; I am well aware of the differences between the models. I have no problem with the Heintz designs per se (my original point), just with what on the face of it appears a disproportionate number of structural failures on the 601XL. Ah yes, another point, trying to rubbish other designs (RV), really isn't going to do anything to make the allegations go away.

 

 

[DGL Fox]

Hi All,

 

So after reading all of the comments on the alledged wing problems of the 601 XL, I see now there is the "B" version, does that mean that all of the wing issues are now resolved with this aircraft?

 

Does anyone have the latest on this issue please?

 

David

 

 

[ianrat]

The 601XL - B has a modified wing ,centre wing carry through, aileron counter balances and other modifications.

 

To my knowledge there has been no other wind failure to a modified 601XL.

 

There was also a large pilot education on the proper flying ability of the aircraft and maintenance of thing like control cable tensions. This was also a problem with the 601.

 

Looks like it all has been fixed now.