 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
msherman95632(at)yahoo.co
Guest
|
 Posted: Fri May 11, 2007 1:25 pm Post subject: 601XL crash in Modesto CA last year |
 |
|
I have read some posts in the past that seem to question the lack of detail on the NTSB report of this crash. So, although it seemed clear to me about the wing attach bolts, I thought I would go back and read it again. These are some NTSB quotes and my understanding of them.
"The Federal Aviation Administration airworthiness inspector that responded to the site noted that the wings remained attached to the center section carry-through spar via their respective main spar bolts."
"The airframe inspection revealed that the wings remained attached at their respective wing root attachment to center carry-through spar."
"The main wing aft attach points remained secured to the fuselage in the normal manner."
It seems real clear that the wing attach bolts were installed and tight, by the first two quotes. The third quote says to me that the wing attach points were secured in the "normal manner", the only way the NTSB would know what the normal manner is, would be to look at the prints for building the airplane or have the information given to them from the kit manufacture. As I understand it, a representative of Zenith, did look at the aircraft after the crash. The normal manner to me means the proper AN bolts, the proper layout and the correct quantity, as depicted on the drawings.
If there was a bolt missing, or the wrong type of bolts installed, it would not meet the "normal manner" of installation. So while the report doesn't come right out and say the correct number of bolts and the correct grade was installed, I would guess that if one or more bolts was missing or some cheep grade 2 bolts were installed the report wouldn't say the wing was secured in the normal manner.
Even if the wing was secured with grade 2, hardware store bolts, this was not the point of failure. The wing was. As indicated by the following quote.
"Investigators noted that both wings and the associated main spars showed deformation about the longitudinal, lateral, and vertical axes of the wing with multiple "S" bends and twists in the main spars."
The NTSB determined that the probable cause of this accident was the structural failure of the wings for undetermined reasons.
What we really want to know is the undetermined reason for the wing failure. Which we will never know because of the thermal destruction of the wings because of the post crash fire. I don't think pictures of the attach points of the wing would help us much.
This report, along with the one in the UK tells me that when the 601 is put in an extreme load, for what ever reason, that the wings are the first thing to give up. If you make the wings stronger then something else will break first. You can chase the failure point forever.
I'm building a 701, with a 15 year history no in-flight catastrophic failures to date. Elongated wing attach bolt holes in a 9g aerobatic maneuver was documented however. Along with the rear wing attach bolt holes ripped out when a 701 bounced on landing and ran into a ditch, very abrupt stop.
Not that I wouldn't build a 601. It would be my first choice for a low wing airplane. Just not what my flying needs call for now.
Mark S.
701/912ULS
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
 |
chris Sinfield
Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia
|
| Posted: Fri May 11, 2007 1:44 pm Post subject: Re: 601XL crash in Modesto CA last year |
|
|
You can read it 2 ways..
I read it as the bolts were there on the main spar but not on the aft attachment point. as it just said the attachment point remained attached to the fuse.. very different wording to the main spar paragraph.. Also this aircraft was NOT in any turbulance but in the circut area..
Chris
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
msherman95632(at)yahoo.co
Guest
|
| Posted: Fri May 11, 2007 2:15 pm Post subject: 601XL crash in Modesto CA last year |
|
|
Chris.
How could the bolts be missing and the wing aft attach pont remain secured to the fuselage. This is refering to the wing attach point not the fuselage attach point.
Mark S.
do not archive
---
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
planes_by_ken(at)bellsout
Guest
|
| Posted: Fri May 11, 2007 3:53 pm Post subject: 601XL crash in Modesto CA last year |
|
|
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
paulrod36(at)msn.com
Guest
|
| Posted: Sun May 13, 2007 10:20 am Post subject: 601XL crash in Modesto CA last year |
|
|
<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]--> I just have to put my two cents in here. That's not a very well written report. If the NTSB wants to give me something to work with, how about stating that the rear spar remains attached to the carry-through by means of x AN-x bolts,, and the carry-through remains attached to the fuselage by means of x rivets. If the wing came off, tell me that the rear spar showed evidence of the AN-x bolt having torn through the spar at xx angle. If the wing failed, how about telling me the wing spar fractured (or ribs separated, or whatever,) at xxx station. Then I could extrapolate that to my own wing, and perhaps avoid the same fate. Any investigative report should be written under the Martian Rule: You are telling a Martian, who just got here and has no knowledge of ANYTHING earthly, except the ability to read, what happened.
Paul Rodriguez
601XL/Corvair
DO NOT ARCHIVE
[quote] ---
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
