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CH601 Yuba City Photos Link

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jim.lanier(at)charter.net
Guest

Posted: Wed Apr 23, 2008 12:38 pm Post subject: CH601 Yuba City Photos Link

You can download the zip from here:



www.chemroc.com/CH601/Post_crash.zip



Jim

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 23, 2008 1:01 pm Post subject: Re: CH601 Yuba City Photos Link

So one wing pulled off at the root, and then the other took the center spar with it out the plane when it went. Neat.



 	  jim.lanier(at)charter.net wrote: 	
		  You can download the zip from here:



www.chemroc.com/CH601/Post_crash.zip



Jim

MHerder

Joined: 11 Feb 2008
Posts: 143
Location: Fort Worth TX

Posted: Wed Apr 23, 2008 1:04 pm Post subject: Re: CH601 Yuba City Photos Link

Do Not Archive



I think that it would be appropriate to rephrase your statement.



 	  ashontz wrote: 	
		  So one wing pulled off at the root, and then the other took the center spar with it out the plane when it went. Neat.



 	  jim.lanier(at)charter.net wrote: 	
		  You can download the zip from here:



www.chemroc.com/CH601/Post_crash.zip



Jim

_________________
Zodiac 601 HD
Jabiru 3300
Wood Sensinich 64x47
Finally Flying

Gig Giacona

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

Posted: Wed Apr 23, 2008 1:51 pm Post subject: Re: CH601 Yuba City Photos Link

No, I think it is a pretty good example of where Andy is coming from.



DO NOT ARCHIVE



 	  MHerder wrote: 	
		  Do Not Archive



I think that it would be appropriate to rephrase your statement.



 	  ashontz wrote: 	
		  So one wing pulled off at the root, and then the other took the center spar with it out the plane when it went. Neat.



 	  jim.lanier(at)charter.net wrote: 	
		  You can download the zip from here:



www.chemroc.com/CH601/Post_crash.zip



Jim

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

jim.lanier(at)charter.net
Guest

Posted: Wed Apr 23, 2008 2:01 pm Post subject: CH601 Yuba City Photos Link

Notice photo 019. If the rear spar attachment failed first it could 

cause this kind of cataclysmic failure of the wing and forward spar. The 

main spar is not designed for that type of loading (ie twisting).

This is the problem with sand bag tests. The static test only stresses 

the spar with the type of loading it was designed to handle. My point 

is, one can not assume the problem is with the strength of the main 

spar. Beefing up the main spar would not help in this situation at all..

I can only hope that the NTSB can resolve this. This is one case where 

the sequence of events is extremely important.



Jim



James E. Lanier wrote:

 	  Quote: 	
		   

 <jim.lanier(at)charter.net>



 You can download the zip from here:



 www.chemroc.com/CH601/Post_crash.zip



 Jim

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 23, 2008 2:36 pm Post subject: Re: CH601 Yuba City Photos Link

Whatever dude. Think about it, the entire spar ripped out of the thing, that was my point.



 	  Gig Giacona wrote: 	
		  No, I think it is a pretty good example of where Andy is coming from.



DO NOT ARCHIVE



 	  MHerder wrote: 	
		  Do Not Archive



I think that it would be appropriate to rephrase your statement.



 	  ashontz wrote: 	
		  So one wing pulled off at the root, and then the other took the center spar with it out the plane when it went. Neat.



 	  jim.lanier(at)charter.net wrote: 	
		  You can download the zip from here:



www.chemroc.com/CH601/Post_crash.zip



Jim

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 23, 2008 4:53 pm Post subject: Re: CH601 Yuba City Photos Link

Well, the bolt didn't break. I doubt that was the cause. More importantly, the center spar cap sheared away.



 	  Sabrina wrote: 	
		  Look at Photo #28.    AN5-16A bolts have a defined thread length (17/32" I think).   The most outboard upper bolt has several threads showing--could it be that the AN5-16A's regular height nut was torqued against the last thread of the AN5-16A bolt rather than 6-B13-1?  Is it even an AN5-16A?

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Apr 23, 2008 5:20 pm Post subject: Re: CH601 Yuba City Photos Link

I know, I had a made, I guess a snide remark, about the entire damn center spar being ripped out of the fuselage, that Gig didn't seem to like very much and called me on. What I was getting at in that remark was, "Holy cow, the entire center spar got ripped out and ripped apart the fuselage", but apparently that was lost in translation on him.



This all occurred while these poor people were in the pattern apparently. And per his son, he was an excellent, diligent, healthy pilot no less. And I'm going to guess the wife probably knew how to fly too if the sons are all pilots. Sounds like a pilot family to me. And even if she wasn't a pilot, she probably knew at least the basics. Point being, if the guy had some sort of medical problem out of nowhere, there was in all probability a co-pilot sitting right next to him. Which would lead you to believe, sumpin' aint right with that particular plane anyway. Especially condidering the son doesn't think an explosion occurred. Apparently this is the plane where the rear spar bolts weren't installed. Who knows, maybe, maybe not.



 	  Sabrina wrote: 	
		  Those 4 bolts hold the wings to the aircraft.   This is the only craft where the center spar was pulled out of the craft (that I know of.)  If the other 8 bolts are torqued properly, a pre-flight of the wings would indicate a solid wing but the rubber wing root fairing combined with the spring gear would mask movement between the wing and the fuselage.  It could easily lead to fatigue failure of the 6-B13-1 uprights or overstress 6-W7-2, the rear spar root doubler. See photo 19 (as pointed out earlier.)

PLAV8R

Joined: 22 Apr 2008
Posts: 30
Location: Prior Lake, Minnesota

Posted: Wed Apr 23, 2008 7:12 pm Post subject: Re: CH601 Yuba City Photos Link

Hi Andy,



  My parents were not in the pattern,  They were in normal cruise flight.  The radar reflection indicated no change in altitude or direction. In any phase of flight.  

  Again, I am not trying to be negative.  I would just like to get some answers or good information.

  This is a great group and I wish I had posted a long time ago.



Thanks again, you guys are great.

Don

_________________
Donald J. Dennnehey Jr.
don.dennehey@gmail.com
Prior Lake, Minnesota
Cessna 175 N7656M
Cessna 140 N90123

rdobson

Joined: 24 Apr 2008
Posts: 1

Posted: Thu Apr 24, 2008 1:39 am Post subject: Re: CH601 Yuba City Photos Link

After viewing photos I wonder if the aileron fluttered causing the rivets attaching it to rear spar to begin to unzip, stripping rivet heads one at a time, causing wing tip rotation to over stress rear spar attachment causing main spar to twist and bend . As previously stated the aileron hinge looks too clean to have been firmly attached at impact.



Russell Dobson

leinad

Joined: 19 Sep 2006
Posts: 283
Location: Central Virginia

Posted: Thu Apr 24, 2008 3:50 pm Post subject: Re: CH601 Yuba City Photos Link

Are there any better pictures of the rear spar attach point.  In the few where that part shows, it looks like the bolt head pulled through the rear spar, but where's the doubler plate that should be there? It seams like you'd be able to see it in a few of the pictures, especially after having a bolt head pulled through it.   That attachment point can get a lot of stress, for example when the pilot or passenger steps on the wing to get in and out of the aircraft, and when the flaps are deployed. 

It has also made me wonder if the NTSB looks into things like, whether the plane is built to the plans, or do they just look for more common manufacturer defects.

Dan

601xl plans builder

_________________
Scratch building XL with Corvair Engine

PatrickW

Joined: 27 Oct 2006
Posts: 380
Location: Fort Worth, Texas

Posted: Thu Apr 24, 2008 7:30 pm Post subject: Re: CH601 Yuba City Photos Link

Zoom in on photograph 019.  I believe this photograph is key.  The resolution is good enough to very clearly show that a roughly square shaped piece is missing from the area of 6W7-2 (the rear attachment doubler) of the left wing.  



Note also the deformation of the metal immediately above (note the wing is upside down) the location of the rear attachment bolt position.  I believe this deformation indicates the aft edge of the wing rotated upwards with respect to the orientation of the aircraft in flight.



Also note that the aileron cables have been torn out through the skin and through the 3rd and 4th lightening holes.  This tear pattern could only occur if the aft edge of the wing was rotating upwards.



Finally, look at the compression buckling of metal between lightening holes 1 and 2, which also appears consistent with the aft edge of the wing being rotated up (with the aluminum rib buckling against the resistance of the main spar).



I would highly suggest a close inspection of 6W7-2 on flying XL's.  I bet somebody out there will find two horizontally oriented cracks - one crack above the rear spar attachment bolt, and one crack parallel to the first and below the rear spar attachment bolt.  



Patrick

XL/Corvair

N63PZ (reserved)

lwhitlow

Joined: 15 Jan 2006
Posts: 76
Location: Valparaiso Indiana

Posted: Thu Apr 24, 2008 8:25 pm Post subject: Re: CH601 Yuba City Photos Link

To Patrick and others speculating on possible causes to the Yuma City crash, please understand I do not wish to offend any of you, but please I think we should all be mindful of of a few things.



Please remember that someones family members were lost in this incident, and in this case they also read and post on this list. I'm sure other families who have suffered a similar loss could and probably have been reading our posts. Ladies and Gentlemen, please keep this in mind when responding.



I really want to leave the debate on what happened here to structural engineers who have the training and experience necessary to back up any of  their analysis.



Another post did point out that this community knows more about this aircraft than any one else, and I do believe that to be true. But remember as you look at these pictures of the broken parts, trying to discover what parts failed is important (as Patrick noted below) but to also understand the SEQUENCE in which the failures occurred. Patrick saw the pullout damage to the rear spar attach point, but consider that if the failure was elsewhere then you would reasonably expect the rear attach point to be damaged.  The real question is where did the failure sequence begin??



Larry McFarland, said in another post that we may well find that inferior materials or out of spec materials may well be found to be the root cause. A telling thought. Remember the United DC-10 crash in Sioux City?? Ultimately the failure sequence  was found to have started YEARS before the day of the crash, with faulty materials in a turbine disk, when it was made years before.



The oldest XL in the fleet is the prototype, that I'm sure a number of us have had a ride in. I'd be willing to bet a large amount of dollars that Nick and everybody else at Zenith has already gone out and looked at the rear attachment on that one, a number of times, and found nothing wrong. And don't forget that XL takes a beating at airshows from all of the masses jumping in and out of it to try it on for size. I'd be willing to bet that most of the "tourists" are not as careful as we are around our own airplanes.



I am seeing the light at the end of the construction tunnel on my XL, and I will complete mine if all goes well within the next year. 



And on a cool morning, with a light wind, just after sunrise, while the air is the most stable. I will take my XL to the air for its first flight. I will do so confident in my skills as a builder, my skills as a pilot and in the design of the airplane. I will be prudent and make sure that all is as safe as I can make it. I will take no un-necessary risks. If after all is analyzed about these incidents , and Zenith wants me to change a part or rebuild an assembly then I will gladly do it, But as Gene Kranz, flight controller for Apollo 13 said "lets not make things worse by guessing"



That quote is up on the wall of my shop



Larry Whitlow

601XL Builder

30+ year Pilot

1st time Airplane Builder





 	  PatrickW wrote: 	
		  Zoom in on photograph 019.  I believe this photograph is key.  The resolution is good enough to very clearly show that a roughly square shaped piece is missing from the area of 6W7-2 (the rear attachment doubler) of the left wing.  



Note also the deformation of the metal immediately above (note the wing is upside down) the location of the rear attachment bolt position.  I believe this deformation indicates the aft edge of the wing rotated upwards with respect to the orientation of the aircraft in flight.



Also note that the aileron cables have been torn out through the skin and through the 3rd and 4th lightening holes.  This tear pattern could only occur if the aft edge of the wing was rotating upwards.



Finally, look at the compression buckling of metal between lightening holes 1 and 2, which also appears consistent with the aft edge of the wing being rotated up (with the aluminum rib buckling against the resistance of the main spar).



I would highly suggest a close inspection of 6W7-2 on flying XL's.  I bet somebody out there will find two horizontally oriented cracks - one crack above the rear spar attachment bolt, and one crack parallel to the first and below the rear spar attachment bolt.  



Patrick

XL/Corvair

N63PZ (reserved)

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