The only thing that speaks against aileron flutter , severe or not is that flutter occurs usually only on one side.
But it was reported by the witness that both ailerons were free to flutter. Here again an excerpt from the report: "From his position, he (the witness) could see the bottom of the airplane, as well as both wings, as the airplane traveled north. He additionally noted that while the airplane was banking, both ailerons were "fluttering" at a high frequency. The bank angle increased to almost 90 degrees, when the left wing of the airplane "folded back" and separated from the fuselage. The airplane then pivoted about the lateral axis 90 degrees, and the right wing then separated from the fuselage along with a portion of the cabin. The wings "fluttered” or "twirled" to the ground, while the portion of the cabin continued forward and down to the ground. He recalled hearing three distinct "thuds" as the pieces of the airplane impacted the ground. The witness also reported that during the breakup, the airplane released what initially looked like "confetti," which he later determined to be painted chips of dope from the airplane’s fabric covered wings." While the airplane was banking ..... and the bank increased to almost 90 degrees. Only someone that can not control the ailerons allows that degree of bank. Now the first wing folds back. Then just short thereafter the second wing. Still convinced the flutter was the cause ? During the breakup the confetti like fabric covering is released. Now that would be normal, since the whole thing just rips apart. NOT before the breakup though. Still not convinced that something else was failing that lead to the fluttering of ailerons/wings and then to the breakup in the sequence described? I hope teh NTSB and Mr. Caldwell come to a more precise conclusion. After all they have the evidence, we are just guessing from 2 witness reports. And the fact that Mr. Caldwell points out illegal holes and a crack in the upper spar cap. Hartmut To: [email protected] From: [email protected] Date: Wed, 30 Sep 2009 07:25:00 -0500 Subject: RE: [ercoupe-tech] Re;FYI -Seibring crash Read & Ponder I suspect the cause was severe aileron flutter followed by drastic maneuver followed by fabric separation then catastropic failure of the spar, followed by loss of wings. Bill To: [email protected]; [email protected]; [email protected] From: [email protected] Date: Wed, 30 Sep 2009 12:16:51 +0100 Subject: Re: [ercoupe-tech] Re;FYI -Seibring crash Read & Ponder Was it aileron flutter he saw (and heard) or loose fabric? On 30/9/09 08:15, "Hartmut Beil" <[email protected]> wrote: Ralph. I have the same doubts about the eye witness account. It is almost impossible to see any detail of a plane that flies 1200 feet above you. Now, the plane might have been directly above the witness and maybe the sun was in an angle that mirrored. But the breakup occurred at 11:15 local time I think, ( If it would be Zulu time, the flight would have happened at 6 A.M in the morning), so at least the report. This is the worst time to see anything against the sky. Anyhow. Maybe he could see the detail. If both ailerons were to flutter, the whole control system was broken loose. What I believe is that the upper spar cap broke at one side and the whole wing was fluttering. That made the other side of the spar also loose its wing support and we now had two wings fluttering. THAT you can observe from 1200 ft below. I hope the NTSB will get the details out soon. So the talk "we don't do nothing, the controls were fluttering" will stop. Hartmut To: [email protected] From: [email protected] Date: Tue, 29 Sep 2009 17:44:53 -0700 Subject: RE: [ercoupe-tech] Re;FYI -Seibring crash Read & Ponder "From the second witness's position, he could see both ailerons - the hinged flaps on the control surfaces attached to the wing's trailing edge - fluttering at a high frequency." Hard to believe. Eyewitness accounts are known to be unreliable. “And they flutter that much that a witness from 1200ft below can see them moving.” Even less reliable. 1200 feet away and he can see both fluttering? Ralph Finch ________________ Alon A2 A-188 G-HARY www.ercoupe.co.uk Insert movie times and more without leaving Hotmail®. See how. _________________________________________________________________ Windows Live™: Keep your life in sync. Check it out! http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009
