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teamgrumman(at)yahoo.com
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 Posted: Thu Jan 26, 2012 11:45 am Post subject: Tiger Crash: 11/12/99 |
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This was forwarded to me from gg because it happened in my backyard (sort of).
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I was called to go look at the wreckage in Van Nuys by one of the accident investigators who was also my AP/AI mentor.
I saw the wing and the aileron and noticed the missing counterweights. The counter-weight holes in both wingtips had a tear in the fiberglass where the counterweight arm might go through IF the counterweight had been far enough down into the wind to where the drag on the counterweight might pull it backwards. I noted the aileron stops.
The aileron stops WERE STILL THERE AND THEY HAD NO DAMAGE.
My conclusion, to the friend of mine, was that counterweight had been installed wrong with the bolt that acts as the stop not installed where it should be.
Sarcastic note: Quote: "You don't need a Grumman specific mechanic to work on a Grumman."
Forward to GG if you wish.
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"On November 12, 1999, at 1738 hours Pacific standard time, an American General AG5B, N1195L, was substantially damaged by an encounter with in-flight turbulence while on downwind leg for landing at the Van Nuys, California, municipal airport. ......
The pilot reported that ...... there was an instantaneous jolt of sudden severe turbulence that ended before he could take any action. His left hand was on the flight controls and his right hand was on the throttle. The pilot said the flight control in his left hand felt "like the handle of a sledge hammer when you strike a steel pipe.
.... He felt that the speed was normal, there was no shrieking or wind noise, and the pilot made no control input before or after the turbulence.
---------------- I don't believe this. Anyone who has ever been hit with the slightest turbulence instinctively corrects, or over corrects, it.
One of the aileron mass balance weights was located on November 16, 1999, in the bedroom of an unoccupied apartment where it had penetrated the roof and ceiling. The apartment is located beneath the downwind leg flight path on the east side of the airport approximately midfield.
---------------- I'd like to have seen this. It hadn't been located yet.
The Safety Board investigator examined the aircraft on November 16, 1999. Each wing is assembled in three sections, which are spliced together. The tip section of the left wing, outboard of the second splice, was deformed upward about 5 degrees with respect to the inboard section of the wing. The upper wing skin exhibited compression buckling. In comparing the two damage areas, the buckling was substantial on the outboard wing section and modest on the upper wing skin inboard of the tip splice. The right wing exhibited modest compression buckling over its entire span but was not visibly deformed. There was no visible damage to the fuselage, empennage, or landing gear. The mass balance weights on both ailerons were absent. The steel tubes supporting the mass balances separated immediately forward of the weld attachment to the aileron torque tube in the vicinity of the heat affected region of the weld. Both failures exhibited a shear lip on the top portion and downward bending on the bottom portion. There was no damage to control stops or evidence of over-travel."
----------------- NOTE: "There was no damage to control stops or evidence of over-travel."
If the counterweight had been installed correctly, the forces needed to tear off the weight would have also ripped out the stop.
[quote][b]
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teamgrumman(at)yahoo.com
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| Posted: Fri Jan 27, 2012 10:25 am Post subject: Tiger Crash: 11/12/99 |
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Got a reply . . .
"I'm not so sure. The weight design is a small diameter tube stuck through the larger tube and welded, which changes the grain structure of the Normalized tube. The instantaneous jolt of the turbulence would stress the tube right where it changes section going into the larger tube, and if sufficiently powerful would tear the tube before it had a chance to rotate the aileron so that the bolt would reach the stop."
I appreciate the information, but, based on what I saw, it's very unlikely the entire end of the aileron torque tube could have been snapped off and dragged out without damaging the stops if the bolt had been there.
From: Gary Vogt <teamgrumman(at)yahoo.com>
To: Teamgrumman List <teamgrumman-list(at)matronics.com>
Sent: Thursday, January 26, 2012 11:43 AM
Subject: Tiger Crash: 11/12/99
This was forwarded to me from gg because it happened in my backyard (sort of).
=============
I was called to go look at the wreckage in Van Nuys by one of the accident investigators who was also my AP/AI mentor.
I saw the wing and the aileron and noticed the missing counterweights. The counter-weight holes in both wingtips had a tear in the fiberglass where the counterweight arm might go through IF the counterweight had been far enough down into the wind to where the drag on the counterweight might pull it backwards. I noted the aileron stops.
The aileron stops WERE STILL THERE AND THEY HAD NO DAMAGE.
My conclusion, to the friend of mine, was that counterweight had been installed wrong with the bolt that acts as the stop not installed where it should be.
Sarcastic note: Quote: "You don't need a Grumman specific mechanic to work on a Grumman."
Forward to GG if you wish.
=============
"On November 12, 1999, at 1738 hours Pacific standard time, an American General AG5B, N1195L, was substantially damaged by an encounter with in-flight turbulence while on downwind leg for landing at the Van Nuys, California, municipal airport. ......
The pilot reported that ...... there was an instantaneous jolt of sudden severe turbulence that ended before he could take any action. His left hand was on the flight controls and his right hand was on the throttle. The pilot said the flight control in his left hand felt "like the handle of a sledge hammer when you strike a steel pipe.
.... He felt that the speed was normal, there was no shrieking or wind noise, and the pilot made no control input before or after the turbulence.
---------------- I don't believe this. Anyone who has ever been hit with the slightest turbulence instinctively corrects, or over corrects, it.
One of the aileron mass balance weights was located on November 16, 1999, in the bedroom of an unoccupied apartment where it had penetrated the roof and ceiling. The apartment is located beneath the downwind leg flight path on the east side of the airport approximately midfield.
---------------- I'd like to have seen this. It hadn't been located yet.
The Safety Board investigator examined the aircraft on November 16, 1999. Each wing is assembled in three sections, which are spliced together. The tip section of the left wing, outboard of the second splice, was deformed upward about 5 degrees with respect to the inboard section of the wing. The upper wing skin exhibited compression buckling. In comparing the two damage areas, the buckling was substantial on the outboard wing section and modest on the upper wing skin inboard of the tip splice. The right wing exhibited modest compression buckling over its entire span but was not visibly deformed. There was no visible damage to the fuselage, empennage, or landing gear. The mass balance weights on both ailerons were absent. The steel tubes supporting the mass balances separated immediately forward of the weld attachment to the aileron torque tube in the vicinity of the heat affected region of the weld. Both failures exhibited a shear lip on the top portion and downward bending on the bottom portion. There was no damage to control stops or evidence of over-travel."
----------------- NOTE: "There was no damage to control stops or evidence of over-travel."
If the counterweight had been installed correctly, the forces needed to tear off the weight would have also ripped out the stop.
[quote]hf="http://www.matronics.com/contribution">http://www.matronics.com/contri===============
[b]
| | - The Matronics TeamGrumman-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:
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