PPRuNe Forums - View Single Post - Interesting note about AA Airbus crash in NYC
Old 18th Dec 2007, 10:01
  #315 (permalink)  
PBL
 
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Airsupport,

I am trying to get some information out of you on what you think the problem is and why, and all that's happening is you're calling me names. That may make you happy, but it doesn't give me, or anyone else, any good reason to give credence to anything you say.

I did ask you for your evidence. You could give it directly, rather than making us infer what it might be.

I take it your evidence consists in having seen trapped water inside composite structures on A300/A310 aircraft. Have you also seen disbondment? Have you and your colleagues investigated the disbondment to see why it might have occurred? What were your results?

The primary thinking on disbondment is that it has been caused by contamination with hydraulic fluid, not necessarily water/ice damage. Could you shed some light on why you think trapped water is a greater problem than contamination with hydraulic fluid?

Do you have anything more to say about this that we can find, say, in the recently published report on the Air Transat rudder loss at http://www.tsb.gc.ca/en/reports/air/...7/a05f0047.asp or in the various articles published by Flight International on their Flightglobal WWW site at or linked from http://www.flightglobal.com/transat?

The NTSB also appears to be worried that in-flight separation of the rudder in this scenario could overstress the vertical stabiliser beyond Ultimate Load:

Originally Posted by flightglobal article
Further examination of the vertical stabiliser determined that its two rearmost attachment lugs were damaged due to the high stresses associated with the rudder failure and separation.”

The NTSB also warns: “These high stresses may have been dangerously close in magnitude to those that caused the inflight separation of the vertical stabilizer during the 12 November, 2001 accident involving American Airlines flight 587” which resulted in the death of all onboard.

“A subsequent inspection of the vertical stabiliser noted the aircraft’s rearmost attachment lugs were damaged due to stresses associated with rudder failure and separation,” notes the US safety regulator. “The Board believes that this urgent recommendation, if acted upon quickly, will go a long way to prevent a catastrophic failure of the rudder,” says NTSB acting chairman Mark Rosenker
Originally Posted by airsupport
I have said all along that there is probably more than one cause of this terrible disaster, there always is.
Nobody has disputed this; neither have they disputed that you said it all along.

Originally Posted by airsupport
from being personally involved in detailed Engineering Inspections of these tails in New York, I truly believe the tail structure being weakened by all this trapped water may well have POSSIBLY been another factor.
Lots of other people inspected those tails, knew and know of the associated phenomena, and considered in detail that "all this trapped water may well have possibly been another factor". And then concluded that it wasn't. Can you shed any engineering light on why they concluded that it wasn't and you concluded that it was?

Originally Posted by airsupport
You on the other hand, with no first hand knowledge of the problem, just say NOT POSSIBLE.
I didn't say "NOT POSSIBLE". I said "wasn't the case". That's the straw man thing.

Originally Posted by airsupport
Now you say other Engineers AFTER the tragedy spent much time theorising what might have been, but they did not actually see this problem first hand
Actually, lots of them did.

Originally Posted by airsupport
while the ONLY cause according to you was FIXED by a letter to Pilots
Here's the straw man thing again. I have never said or published anything so remotely contrary to fact as this.

As any lawyer can tell you, if you want to trash someone's views, you can only do so effectively by paying close attention to what those views actually are.

PBL
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