In Memoriam

[Dont call me Shirley]

Good gosh how time passes. Has it really been 25 years?
I had just come home from high school when I turned on the radio in the middle of an interview with a fire fighter. Even before I knew he was describing an air crash, I knew something very, very bad had happened.

 

[Garfield1966]

I do not feel like researching this so is this the one where the DC10 lost the engine and drilled it's self into the ground?

 

[mweiss]

Not the most reverent way you could have phrased it, but yes. That was the DC-10 at ORD that lost its left engine just before V1. Hydraulic lines were torn by the ripped-off pylon, causing the slats on the left wing to retract. When the pilot slowed the aircraft down per procedure to perform a go around, the left wing stalled. There was no chance to recover. All passengers perished, as well as two (?) people on the ground.

It was this incident that led me to learn as much as I could about airline safety.

 

[Dont call me Shirley]

Yes. The crash did not occur because of the loss of thrust, but from the uncommanded retraction of the left wing slats. When the engine pylon seperated, it severed the hydralic lines that kept the slats extended on the left wing and the slats retracted. The slat disagreement warning system was powered by the nbr 1 engine's generator (the engine that came off) so the flight crew could not know about the asymetrical (sp?) slat condition. The left wing stalled, the right wing continued to provide lift, causing the DC-10 to roll over and crash.

Even with the asymetric slats, the crew could have avoided the stall, had they known what was happening.

 

[TWAnr]

It was determined, in the course of the NTSB investigation, that the engine and the pylon separated from the wing due to improper and unauthorized maintenance procedures.

 

[1AA]

Here is a photo of aircraft N110AA just before impact.

 

[mga707]

I do not feel like researching this so is this the one where the DC10 lost the engine and drilled it's self into the ground?

Insensitive jerk.
And ignorant, too. Anyone with any knowledge of airline history remembers what happened on May 25, 1979!

 

[mweiss]

It was determined, in the course of the NTSB investigation, that the engine and the pylon separated from the wing due to improper and unauthorized maintenance procedures.

Specifically, the issue involved the installation of pylon-mounted engines on the DC-10. Two smaller bolts attach the pylon to the wing, while one larger bolt attaches the engine to the pylon. MacDAC said that the pylon needed to be attached to the wing first, then the engine to the pylon.

This required two forklift operations, one for the pylon and then another for the engine. AA decided to attach the pylon to the engine first, and then attach the whole assembly to the wing, thus saving time and money by having only a single forklift operation. They asked MacDAC for approval in doing this, but got a lukewarm recommendation against it instead.

Turns out that part of the problem was related to how forklifts work. When the hydraulics lift the whole assembly, the fork tends to settle slightly over time. Apparently, one of the results of this is that the first bolt would be installed with the whole assembly, then as the second is being installed, the fork slowly sinks, placing the whole weight of the assembly on the single bolt. This resulted in premature failure of the pylon bolts, as witnessed in AA191's case.

I'm doing all of this from memory, so I might not have all of these facts right.

 

[mweiss]

Even with the asymetric slats, the crew could have avoided the stall, had they known what was happening.

What, if anything, was done to ensure that this particular situation wouldn't recur? Specifically, I am referring to the unindicated uncommanded asymmetric slat issue.

 

[Wretched Wrench]

This tells the official story:

http://amelia.db.erau.edu/reports/ntsb/aar/AAR79-17.pdf

There is more. You know, the usual cover up.

 

[flyhigh]

I thought I had read at one time that CO actually came up with this procedure and that it was approved...this crash, however, led to a review of the process which had authorities revoke it as an approved procedure.

 

[AAmech]

They asked MacDAC for approval in doing this, but got a lukewarm recommendation against it instead.

I've read that it was a lukewarm "approval". Douglas was not crazy about this procedure at all but gave its approval anyway. As a mechanic I'm very doubtfull that AA would use a maint procedure that had actually been flat out Rejected by the manufacturer. You would be in direct conflict with the Law in that case. CO did not invent this procedure but adopted it from AA.

 

[AA191]

I lost family on that flight and it changed my life forever. A heartfelt sympathy to all that lost famliy on that clear May afternoon.

 

[Wretched Wrench]

CO did not invent this procedure but adopted it from AA.

I believe you've got it backwards. Can you verify or substantiate that?

This Thursday evening, The History Channel will air a new and compelling documentary--"The Crash of Flight 191"--that reconstructs the disaster, the loss and the ferocious blame game that followed.


http://www.chicagotribune.com/news/local/c...ll=chi-news-hed

 

[Garfield1966]

Insensitive jerk.
And ignorant, too. Anyone with any knowledge of airline history remembers what happened on May 25, 1979!

Insensitive? May be. Like you have never made an off color comment that offended someone. If I offended anyone I'm sorry. Ignorant? DELETED. I was not even old enough to vote when that happened.