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Tragic Accident - more stupid conjecture.
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Jari Kaija

Joined: 23 Feb 2006
Posts: 69

Posted: Fri Mar 10, 2006 10:28 am Post subject: Tragic Accident - more stupid conjecture.

 	  Quote: 	
		   Few builders would know what to do with static testing if they were 

 furnished and required as in Finland


	


Hmmm... in here, Finland, we do not need to do static tests at all

to planes, what has tested already in other (approved) countries.



IF we are going to build totally new plane model or we are going

to make some welds to structural parts, we have two way to prove 

structures. 



Ie. with welded parts we can use static test without breaking parts 

(using only forces, what plane should handle already) and we can 

make several demonstration welds and prove with them, that person 

is capable to do whatever he is doing. We can also use penetration

chemicals to prove satisfactory welds.



All building process are monitored by personal, CAA approved 

supervisor, who take cares, that builder won't make any mistakes 

AND do not try to go there, where the fence is lower...



damn! I really need more practise with english. I hope, this msg 

was readable

crvsecretary(at)aol.com
Guest

Posted: Fri Mar 10, 2006 10:34 am Post subject: Tragic Accident - more stupid conjecture.

Jari:

 

Your english is just fine and VERY understandable.  Please continue to add your thoughts and perspective from your fine country on this list.

 

Regards,

 

Tracy Smith

601XL N458XL (reserved)

do not archive

 

--

moorecomp(at)yahoo.com
Guest

Posted: Fri Mar 10, 2006 10:52 am Post subject: Tragic Accident - more stupid conjecture.

Bill,



I will step out on a limb here for you and make a few

comments. According to the accounts I have read, the

builder was described as being immaculate in his work.

A comment I hope we all can have said for our work.

The pilots were both very experienced. 



The NTSB approaches investigations based on facts. The

fact is we have what is called an "upset from normal

flight", caused by structural failure of the wing.

Then they must determine what caused the failure. Were

any of the wing attach bolts left out, or did they 

fail for some other reason? - Check yours.



This accident occurred in the pattern (low speed). Did

something in the flap control circuit fail when the

flaps were being used and allow the flaps "flap",

either together or independantly, without restraint?

Would this create high enough loads to fail the wing?

- Check yours.



What would happen if an aileron control cable broke or

a swage failed? Would it allow the ailerons to flutter

and destroy the wing, even at low airspeed? - Check

yours.



I know the 601 has been flutter tested by the

manufacturer, but all of the technical articles I read

say there will be diferences between aircraft of the

same model, due to variances in things like circuit

friction, cable tensions, added weight aft of the

hinge line (i.e. electric trim or fixed tabs). I am

not suggesting this accident was caused by high speed

flutter. I am concerned as to what would happen to

these large, unbalanced control surfaces after a

failure in the control circuit, and they are allowed

to flutter without restraint at any speed.



General aviation airplanes are required in FAR Part 23

certification to be able to maintain control after a 

failure of a primary flight control, by using the

remaing controls (trim, rudder and such). I know this

doesn't apply to AB/EX, but it is something that

should be part of any good control system design.



I am inclined to go with aileron control system

failure and subsequent flutter that caused aerodynamic

forces great enough to deform and eventually fail the

spar.



Ducking



Do not archive



Craig Moore A&P

701 builder wannabe



--- JAPhillipsGA(at)aol.com wrote:



 	  Quote: 	
		   

 JAPhillipsGA(at)aol.com

 

 Mark, thanks, but speculation can be healthy.

 Remember, we all want the "e" 

 in experimental to be a small "e". If  NASA  did a

 little more speculation and 

 grasping we might have a couple more space shuttles

 parked around Florida. 

 This body of builders has a boundless collective

 knowledge and experience. We 

 should encourage the thought process. If you follow

 the NTSB reports you will 

 note very quickly that many, many accidents have no

 definitive resolution. I have 

 read hundreds of accident reports that NTSB offered

 no reason. We assemblers 

 of XLs need to be proactive in an effort to

 determine what would cause such an 

 event and self inspect. The prudent pilot and

 assembler would be remiss not 

 to try. Best to you, Bill of Georgia

Jari Kaija

Joined: 23 Feb 2006
Posts: 69

Posted: Fri Mar 10, 2006 11:00 am Post subject: Tragic Accident - more stupid conjecture.

 	  Quote: 	
		   from your fine country on this list.


	


    You didn't seen Conan's wednesday? episode

stutzman(at)stutzman.com
Guest

Posted: Fri Mar 10, 2006 12:24 pm Post subject: Tragic Accident - more stupid conjecture.

On Fri, 10 Mar 2006, Jari Kaija wrote:

 	  Quote: 	

 > Few builders would know what to do with static testing if they were

 > furnished and required as in Finland

 Hmmm... in here, Finland, we do not need to do static tests at all

 to planes, what has tested already in other (approved) countries.

 IF we are going to build totally new plane model or we are going

 to make some welds to structural parts, we have two way to prove

 structures.

 Ie. with welded parts we can use static test without breaking parts

 (using only forces, what plane should handle already) and we can

 make several demonstration welds and prove with them, that person

 is capable to do whatever he is doing. We can also use penetration

 chemicals to prove satisfactory welds.

 All building process are monitored by personal, CAA approved

 supervisor, who take cares, that builder won't make any mistakes

 AND do not try to go there, where the fence is lower...

Hmm, maybe things have changed.

The first Bowers Flybaby built in Finland was statically tested.  The test

report (translated into English) is at

http://www.bowersflybaby.com/safety/Finnish_Load_Report.pdf. This test was

done sometime in '70s and by that time the Flybaby prototype had been

flying for more than decade at that point.

Frank Stutzman

Bonanza N494B     "Hula Girl"

Hood River, OR

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Fri Mar 10, 2006 12:35 pm Post subject: Re: Tragic Accident - more stupid conjecture.

The problem with all of these possible problems and the idea that this group could come up with a fix "for this weekend" is that no one here even has access to the plane.



There was, I believe, one witness that saw the wing fail. It could have been an optical illusion. We don't know.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

JAPhillipsGA(at)aol.com
Guest

Posted: Fri Mar 10, 2006 12:48 pm Post subject: Tragic Accident - more stupid conjecture.

Craig, thank you for your insight. Did you happen to read the AOPA article on 

the Beaver that the wings were destroyed from a low speed flutter (115mph) as 

a result of aileron imbalance? Frankly, I had no idea that ailerons had to be 

balanced. Surely, such destruction on the Beaver was unanticipated and the 

Company had tested the design before marketing. As an A&P, you may have 

encountered aileron imbalance. What would we simple assemblers need to look for that 

could forestal such an event occurring in our XLs. Thanks, Bill

JAPhillipsGA(at)aol.com
Guest

Posted: Fri Mar 10, 2006 12:57 pm Post subject: Tragic Accident - more stupid conjecture.

Gig, thanks and you made a good point. Have you had a chance to read the 

preliminary NTSB report ? My point is I think we should be part of the process not 

just patient recipients. I understand our XLs have been tested and this has 

not happened before. I encourage you to read the AOPA post article on the low 

speed flutter of a Beaver that destroyed the wings as a result of an aileron 

imbalance. Never happened to a Beaver before either. Have you read anything from 

ZAC concerning balancing ailerons on a XL ? Hope you are well and I 

appreciate you opinion, Bill

john.marzulli(at)gmail.co
Guest

Posted: Fri Mar 10, 2006 1:35 pm Post subject: Tragic Accident - more stupid conjecture.

Here is the pilot's account of the Beaver incident.



http://www.aopa.org/pilot/never_again/2006/na0603.html



Sounds very different than what the witness reported in the prelim NTSB

report.



On 3/10/06, JAPhillipsGA(at)aol.com <JAPhillipsGA(at)aol.com> wrote:

 	  Quote: 	
		  

 



 Gig, thanks and you made a good point. Have you had a chance to read the

 preliminary NTSB report ? My point is I think we should be part of the

 process not

 just patient recipients. I understand our XLs have been tested and this

 has

 not happened before. I encourage you to read the AOPA post article on the

 low

 speed flutter of a Beaver that destroyed the wings as a result of an

 aileron

 imbalance. Never happened to a Beaver before either. Have you read

 anything from

 ZAC concerning balancing ailerons on a XL ? Hope you are well and I

 appreciate you opinion, Bill

Jari Kaija

Joined: 23 Feb 2006
Posts: 69

Posted: Sat Mar 11, 2006 2:34 am Post subject: Tragic Accident - more stupid conjecture.

 	  Quote: 	
		   Hmm, maybe things have changed.


	


    I think, I should know it 



 	  Quote: 	
		   done sometime in '70s and by that time the Flybaby prototype had been

 flying for more than decade at that point.


	


    Magic word: 'Prototype'.



rgds:

Jari Kaija

www.jarikaija.com

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