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Rotor-EZ N2992 Accident Report Pointer


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Folks:

 

I was asked by Bob Tilley to be a member of an accident evaluation team for Rotor-EZ N2992 which crashed in May, fatally injuring the pilot. I have posted the accident evaluation at:

 

http://www.cozybuilders.org/N2992_Accident_Eval/

 

The evaluation team consisted of Bob Tilley, Steve Wright, myself, and one other well respected member of the canard community who prefers to remain anonymous.

 

This analysis is based on some first hand visual inspection, visual inspection of photographs of the crash site and wreckage, verbal reports of eyewitnesses, and a small amount of testing of crash aircraft hardware and equivalent hardware. Although this report was written by Marc J. Zeitlin, it is the forensic engineering judgement of the whole team, and this analysis and the resulting conclusion is the consensus opinion of all four people on the investigation team.

 

I believe that this analysis is far more detailed and accurate than anything the NTSB is likely to produce, given the lack of familiarity with the airplane type and canard concerns, and the small amount of time devoted to the investigation.

 

This is clearly a generic "canard aircraft" issue, and the canard-aviator's mailing list is the venue which presents itself to the widest canardian audience. Although I have posted the announcement of the publication of this report to the COZY mailing list, the Canardzone Forum, and the Canard Aviation Forum as well, I do not want to carry on four conversations about the same thing. If other members of the investigation team would like to reply in other venues, that is certainly their choice - in the interest of time and energy (mine), I will only follow discussions on the C-A list.

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While for the most part this is not an SQ2000 airframe issue, I appreciate and commend the effort to keep it objective and have learned a few practical things.

 

1. Use a 45 degree angle to attempt turning back to airport.

 

2. Do a gear up landing (I have full retracts) in rough terrain - on crash the fixed gear reaction apparently catapulted Paul backward from his seat.

 

3. Try to keep some speed up in emergency landing - don't try to land at stall speed.

 

4. Watch W&B especially canards. Although I have tested my unit at rear CG, I stay away from it by at least 1". You are welcome to download the "free" builder software with a CG calculator I made http://www.abri.com/sq2000/Homebuiltlog.html

 

5. While it is more difficult to build jet fighter like restraints in many 4+ seater today's aircraft (with reclining seats) because of the greater surrounding "living" space, this accident was a very specific situation that may never happen again. An example: if Paul Conner survived he would have no trouble getting ("falling") out of the aircraft - while in a tight restrained aircraft, individuals sometimes get trapped and burned alive. Which situation risks are more probable is a better question. Another example: because of the comfort/convenience factor and less probability that a four+ seat automobile sedan will be involved in a rollover or crash than a racing car, sedans are not equiped with extensive restraints and rigid seat and body cage structures that race cars have - even knowing that it could save lives.

 

One exception I take is the statement: "We do NOT have any evidence that SQ/KLS ever did any stall/deep stall tests on the SQ2K.." I find that silly. How would any kit manufacturer not do CG range tests. SQ2000 has been around for over 7 years and Stan Mongomery distinctly informed me that tests were done from 2.5" in front to 2.5" behind the CG published range. It would have been simple to pick up the phone and ask Stan what tests were done (irregardles that he was not on the team) instead of "we do not have any evidence..." - a nice catch all. I could believe the moon is made of green cheese and state that "I do not have any evidence to the contrary.." while not bothering to find out from those who have been on the moon.

 

BTW. Stan Montgomery was not invited by Bob Tilley to be on the "team". Bob asked me to check with Stan, earlier in the game. But Stan was not happy that another particular person was apparently on it. Later that member was not put on the team but no further effort was made to invite Stan. I also asked for some information - crash photo's - but received nothing until I discovered this "final report".

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I'd like to add a conjecture to the scenario. Maybe Paul Conner deliberately tried to land flat hoping to survive that way instead of forward collision with trees. He bled all the speed with the 90 degree turn and then leveled and pitched the aircraft up (falling leaf maneuver) near the ground and then pancaked. He was a skilled pilot and could have done that. What he did not count on was the backward reaction force of the fixed gear on impact.

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I also thank the folks involved, but take exception to the statement regarding deep stall.

 

"A deep stall impact involves a much higher descent rate than a gliding descent entails, along with an inability to control the impact point, due to lack of directional and/or pitch control. {..}"

 

The Velocity testing found that, in fact, deep stall entailed very low decent rates. They very likely are not survivable on land, but they certainly are at sea since more than one person has (with the old style Velocity seat, much like the Cozy). To quote the test pilot "Amazingly, Carl says that he could stick out a hand and feel hardly any air rushing against it as the Velocity descended ever nearer the ocean of St. Augustine. Although he was wearing a 'chute, he ultimately chose to ride the airplane down... and suffered no injuries." At high speeds water is only slightly less harmful than land. They reckoned that the descent rate was from 15-20 MPH. For reference 20 MPH is about 30 fps.

 

 

See the discussion at http://www.velocityxl.com/Downloads/VelocityDeepStall.pdf

---

Brett Ferrell

Velocity XL/FG

Cincinnati, OH

http://www.velocityxl.com

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Paul, I appreciate your feedback here, and can understand where you're coming from as a SQ2000 builder-flyer.

 

Since Marc has setup for the Canard Aviators mailing list to be the main point of direct discussion, and has summarized a reply to several messages with feedback, I am copying Marc's summary reply made on that list here. With this, we can now discuss freely.

 

Folks:

 

I've collected the questions that folks have asked regarding this investigation and will reply to them en masse.

 

1) Chris VanHoof asks:

 

>How are our "as per plans" seats, compared to and in relation

>to the seat in the investigated plane?

 

The VE, LE and COZY seats are part of the fuselage structure. The SQ2000 seats are similar to the Velocity seats, in that they are individual seats with seatbacks that fold forward for rear seat access. As Bob Tilley stated, the side hinges are thin aluminum plates, and the structure of the seat is not dissimilar from a lawn chair. In photo 100_3046.jpg, you can see that the seat(s) have come apart and folded back (even the passenger seat, which did not have a person in it). Other photos (not on the web page) clearly indicate that both the front and rear seat sections came apart near the hinges.

 

2) Al Wick asks:

 

>Anyone dismantle the bad injector to determine what is

>affecting it's output?

 

Apparently after determining the restriction of flow in the injector, an emotional reaction on the part of the tester rendered the injector unfit for further testing.

 

> Possible contamination post crash?

 

Highly unlikely - the engine was intact in the engine compartment, still attached to the engine mount and firewall. The mount was bent, but the injectors were still in the engine and the engine in the engine compartment.

 

>How about that unporting causing shut down?

 

Which unporting are we talking about?

 

> He had no header?

 

There was a header tank in the fuselage which fed the high pressure EFI pump.

 

>What about the seat belt attach points? Did they give up in crash?

 

It's difficult to say. In order to get the pilot out of the aircraft during the rescue, damage was done to the fuselage. Photos indicate that the seatbelt attach points seem to be in the appropriate place.

 

> Can you explain more about conclusion of belts not helping?

 

Yes. Since the seats collapsed and the pilot was found in the rear seating area, it's clear that the seatbelt/seat combination did not restrain the motion of the pilot's body during the crash. Also, there is only one shoulder belt - not the dual belts found in the VE, LE, and COZY aircraft - a single belt is not nearly as effective as dual belts.

 

3) Bob Foster asks:

 

>...Was the engine's psru gear box intact?

 

I believe that no damage was found to the PSRU.

 

4) Glen Whittaker asks:

 

>Did the SQ2000 designers particpate in the accident investion or

>provide any input?

 

My understanding is that the designers (Stan Montgomery, in particular, whom Paul Lee mentions below) did not participate in the NTSB investigation, nor did they participate in this investigation after being asked to do so.

 

5) Dale Rogers asks:

 

>... Even I, a relative newbie to

 

>rotaries wouldn't miss the center housing injectors, if

>they were there.. Was that not the case?

 

While two rotary engine experts were asked to participate, and agreed to do so, only one of them did, and his participation was minimal, at best. However, that being said, Joe Hull (on the COZY list) had many discussions with the pilot of N2992 and states categorically that N2992's engine only had one injector per rotor.

 

6) Paul Lee writes:

 

>One exception I take is the statement that "We do NOT have any

>evidence that SQ/KLS ever did any stall/deep stall tests on the SQ2K

>aircraft to verify the rear CG position and margin for deep stall".

 

>Stan Montgomery informed me that the the factory unit was tested to >within 2.5" rear of the CG range to beyond the front of published CG.

 

Let's assume that Mr. Montgomery is reporting the truth to you. Tested to "within 2.5" of the rear of the CG range" is not even testing the full range of PUBLISHED CG RANGE possibilities. The CG range in the SQ2000 is reported to be approximately 6" - if the testing was done only to within 2.5" of the rear, that's barely past 1/2 way in the CG range. Stalling an aircraft at 2.5" in front of the rearmost point in the CG range tells you absolutely nothing about what will happen when you move the CG 2.5" aft of that, and certainly not what would happen if you move the CG 2" even further back than that.

 

Even assuming that the SQ2000 is perfectly safe AT the rearmost published CG position (which, by your own statement, we have no information regarding, but let's assume it's the case), a CG 2" to the rear of THAT is almost guaranteed to lead to a deep stall in a high AOA situation - it most certainly would in a COZY. If the W&B analysis is correct, and the CG was 2" PAST the rearmost allowable point, testing only done within the CG range wouldn't have mattered anyway.

 

The front CG testing that they may have done is not germane to the issue of deep stalls.

 

>.... It would have been better to verify with the

>manufacturer rather than "WE do not have any evidence" simple

>conclusion.

 

Mr. Montgomery was asked to be a part of this investigation. For whatever reason, he chose not to do so.

 

>..... I am still curious why there is not such extensive private team investigations about other LEZ's, Cozy's or other Rotary powered aircraft crashes.

 

Because in the past, RAF (in the person of Mike Melvill, Burt Rutan, or some other qualified individual) assisted in the official NTSB investigation of VE and LE accidents (or conducted their own), and Nat Puffer was extremely active in investigating COZY accidents. RAF would publish investigation results in the "Canard Pusher" Newsletter (all available on the web for public access), and Mr. Puffer would publish investigation results in the COZY Newsletter (also available on the web for public access).

 

There is no SQ2000 newsletter, and since Mr. Montgomery did not participate in the NTSB investigation, a friend of the SQ2000 pilot felt that a private investigation with knowledgeable people would be the best avenue for trying to find the truth, inasmuch as it's available to be found.

 

I hope this answers more questions than it engenders.

 

--

 

Marc J. Zeitlin mailto:marc_zeitlin@alum.mit.edu

http://www.cozybuilders.org/ Copyright © 2005

Paul, Marc was obviously confused with the specifics regarding your statement "...the factory unit was tested to >within 2.5" rear of the CG range...", which you clarified in the wording of your post here ("...tests were done from 2.5" in front to 2.5" behind the CG published range.")

 

With a round of the back-and-forth now in context, I feel free to freely discuss here.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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BTW. Stan Montgomery was not invited by Bob Tilley to be on the "team". Bob asked me to check with Stan, earlier in the game. But Stan was not happy that another particular person was apparently on it. Later that member was not put on the team but no further effort was made to invite Stan.

Apparently Stan was invited to investigate a fatal crash of a kitplane his company manufactured. I don't know the details of the disagreement between Stan and the 'particular person', but the event at hand should have superceded ANY personal disagreement between the manufacturer and another party. In fact, this would have been all the more reason why Stan should have been on the team.

 

It's unfortunate, but Stan has decided to be in a position where he and his business are unable to objectively comment on the crash. To me, this is a most telling attribute of the business behind the SQ2000 kitplane.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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> >>>Apparently<<< (doubts?) Stan was invited to investigate a

> fatal crash of a kitplane his company manufactured. I don't know the details

> of the disagreement between Stan and the 'particular person',....

 

John,

 

Do we speak English? How many times I have to say this.

1. The only person who "suggested" it to Stan was me. STAN WAS NOT INVITED by Bob Tilley or the rest of the team. Did you ask Tilley if he did? I did give Bob Stan's phone number and suggested he could phone him after finding out that the other person was not on the team but apparently that was not so important to Bob. I have records of our emails.

 

2. The information Stan got from NTSB was that it was not an airframe issue. And indeed the current report does not make it an airframe issue except for the seat restraint - which up to the builder - and the silly comments about the CG factory testing. The last issue is really the only one I corrected and pragmatically the whole thing is not an issue unless you try to make it one.

 

In my opinion it really turns out that Stan did not even need to be invited since it is not an airframe issue. If you have quarels with non-racing car seat restraints then talk to Velocity folks too, talk to zilion other certified and experimental aircraft owners too, who have automobile like seats with simple restraints.

 

This "Stan chose not to participate" is really an irrelevant, emotional, political gobledygook.

 

I personally, have no plans removing my sliding/reclining seats and replacing them with a racing car type of restraints/cage. I think this pride in your own aircraft type has gone too far.

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Do we speak English? How many times I have to say this.

What sort of response are you trying to get with this?

 

1. The only person who "suggested" it to Stan was me. STAN WAS NOT INVITED by Bob Tilley or the rest of the team.

Sorry, I mistook Marc's reference to mean that Stan was invited. It now appears fair to say that he was informed of some sort of investigation...

 

My gripe here is biased with prior disappointment in the KLS endeavor as giving hope to the SQ2000 kit. For whatever reasons (that I'm not trying to go into here) the SQ2000 kit does not present itself as a viable choice to new builders. I'm not making this up, or being political.

 

I think this pride in your own aircraft type has gone too far.

That's certainly not where I am coming from, and I didn't get that to be where the team's report was coming from.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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My gripe here is biased with prior disappointment in the KLS endeavor as giving hope to the SQ2000 kit. For whatever reasons (that I'm not trying to go into here) the SQ2000 kit does not present itself as a viable choice to new builders. I'm not making this up, or being political.

 

Thank you for being more forthright admitting that you have a bias. Very few people will do that.

 

I am pragmatic: you buy the kit, construct it and fly it. What else does a viable choice mean?

 

If you read my website ( http://www.abri.com/sq2000 ), I expressed concern about KLS staying in business in 2001 when I bought the kit - so I purchased everything in order to be able to finish it (Joel Conard did the same thing). Here it is 2005 and Stan is still in business, same factory, same place. Want his phone number?

 

Stan is a prolific designer/builder. In the last few years he has designed and tested a kit to compete with Cesna caravan - the kit was displayed at 2002, Sun-N-Fun. Stan has been very helpfull throughout my construction period as he is to other builders. This year I trounced a couple of RG springs and he gave free replacements. He has done similar things for other builders. From all my encouners with him, he is a friendly, sociable fellow - although somewhat timid so would likely loose political public battles.

 

I must admit that I have a bias too which is that Stan stays in the kit business so I can continue getting the good tech support that he has given so far.

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I am pragmatic: you buy the kit, construct it and fly it. What else does a viable choice mean?

The only way I would buy a kit is how I believe you did -- purchase everything up front.

 

...the SQ2000 kit does not present itself as a viable choice to new builders.

By that comment, I mean only "not viable" considering:

  • being unable to purchase the entire kit all at once
  • not seeing the vendor with enough market presence (in Kitplane magazine, at Sun-n-Fun, Oshkosh, etc.)
I can understand the costs of marketing, and whether operations could actually fund showing up at the major air shows. However, a cheap ad in Kitplane and a Web site need to be a requirements in this business.

 

The situation holds true for the present incarnation of www.aerocad.com as well -- another hopeful canard kitplane.

 

My bottomline is that I'd love to see both vendors do VERY well, and only become frustrated when I'm teased by the thought of that happening.

 

I must admit that I have a bias too which is that Stan stays in the kit business so I can continue getting the good tech support that he has given so far.

I understand entirely, and only suggest directing some of this energy at the manufacturer instead of the crowd that might have actually bought an SQ2000 kit if it were known to be available.

 

Paul, I'd love to see your plane someday, and wish you all the best until that happens. I'm sure if you made the trip to Rough River you would be well-received. If it were legal, Stan should cover your expenses to get there.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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