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HAWK21M
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The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 1:33 pm

Last Week.The Regulatory Authorities organised an Aviation Safety week & amongst a few safety programmes organised at Various airlines,Out at the Airline I work,there was a presentation on the Impact of FOD & how it affected the concorde project,leading to the Final Fight of this Supersonic Machine.

After watching the Video presentation & debate/Discussion that followed the Incident of how this type & on this particular occassion all events went against the persons flying this craft that day.

Trying to Figure out How the Ending could have been different.
Had the DC10 Engine Panel not fallen off on the Runway.
Had the ATC noticed the Flames earlier.
Had the Fuel tank panel not got knocked off
Had the Wire in the MLG not got cut

I'd like to hear the opinion of more learned persons from the Field on the same.











regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
EMBQA
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 3:10 pm

..and add to your list of 'what if' questions.....What if they had fixed these issues after the first two times it happened...? This was the third wing puncture event after a tire failure.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
David L
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 4:22 pm



Quoting EMBQA (Reply 1):
This was the third wing puncture event after a tire failure.

The last incident was nothing like any of the previous ones. On that fateful day, a 2 metre chunk of tyre slammed against the underside of the wing at high speed and the resulting shockwave caused the fuel tank to rupture from within. As far as I know, nothing like that has ever happened to any type, before or since, and no-one seems to be entirely sure what would happen if it did.

Having read and heard so much from those who had first hand experience, I don't believe it's fair to suggest that they should have seen that one coming. It certainly isn't the only time an aircraft has been fatally damaged by a burst tyre.

Wait till GDB gets here!  Smile
 
GDB
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 5:21 pm

Well David L nailed it, I was involved within the BA Concorde Engineering operation at the time, so saw it all up close.

We really were stumped by how a FOD incident, could lead to such a destructive chain of events.
FOD issues were known, in the early days, some bad incidents, including that notorious one to an AF aircraft in 1979, led to a range of design and procedure changes, (including new tyres), that prevented a repetition of severe ones.
The notion, popular in the media, that nothing was done, is an outright lie.

An aircraft operating in Concordes unique envelope, with it's design, was always going to be more FOD damage prone, that was always understood too.
In 1993, a BA Concorde (G-BOAB), had a double burst, that blew the spray deflector off, it being buried in the wing.
This led to a retaining strap being fitted, the deflector had meant to shatter on any impact, it did not in this instance, hence the changes.
This would be the last major FOD incident before the AF crash.

Small wonder that at first, this was suspected as being maybe a cause in the AF4590 crash, since AF had not fitted the retaining strap, they did not have to, the authorities never made it mandatory.
When this was eliminated as a cause, the confusion grew.
We knew what Concorde tyre bursts could do, this crash seemed way beyond that.

In time, what David L mentioned came to light, it was certainly a bizarre chain of tragic events, that could not have been foreseen.
But, the offending FOD, part of the DC-10 thrust reverser assembly, was meant to be made of aluminium, for some reason, after servicing at Bedek Aviation, one made of titanium was fitted, this was the FOD.
This is a much harder material, it was not crushed by the weight of the aircraft running over it, only distorted, it damn thing acted like a knife, slashing the tyre in a way unseen in ANY related event with FOD, in the whole history of civil and military jet aviation.

There have long been fears about 'illegal parts' being made of inferior, less durable materials, here a crash was caused by one that was the opposite, who'd have thought it?
Had this FOD been of the correct material, you still might well have seen a tyre burst, but it would have not acted in the same manner on the tyre, if it had burst, the debris would have been much smaller, lighter, damage might still have been done, but a small fuel leak would not have led to the whole chain of events that downed F-BTSC.
The fuel gushed out of F-BTSC's damaged tank at an enormous rate, aside from all the effects of the aircraft itself, this rate of loss lowered the flash-point.

These revelations in spring 2001, altered the whole return to flight programme, the number of tank liners to be fitted, (a very difficult job), was much reduced, then Michelin unveiled their NZG tyre, a step change in tyre design, an adaptation of a design already in the works then for A380 and A340-500/600.
Knowing then, what was not known 6 months before, the fitment of NZG's would have sufficed, in pure technical terms, but the rest of the effort was well underway.

Reflecting back now, I really think there was another cause to the early bad incidents, ultimately too for AF4590.
There were so few Concordes in service, that the usual operational experience enjoyed by other types, took much, much longer to grow. All airliners in service, rack up Airworthiness Directives, Service Bulletins, based on operational experiences, including safety related ones, it just did not happen at the usual rate for Concorde, which was also far from a normal airliner. Others soon have tens of, then hundreds of airframes in service, all those different operators, racking up all those hrs and cycles, with incidents/issues leading to mods, mandated changes.

This could never happen with Concorde, after the early incidents often cited, the BA grew in number, both operators increased the flying rate, but serious incidents reduced.
But all the while, we were out on a limb here, no one else had operated a SST before as well.

I do recall however, some incidents where a tyre burst started a chain of events that led to aircraft being lost, IIRC, two involved B727's in the 70's and 80's, one or two involved DC-8's.

This account of the return to flight, touches on many of the issues, it uses extensive sources from within, is a very comprehensive account, it was written in late 2002.
http://www.concordesst.com/returntoflight/rts/rtsindex.html

[Edited 2007-12-22 09:24:17]
 
EMBQA
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 7:19 pm



Quoting David L (Reply 2):

The story I've read about a flight taking off out of IAD had a tire fail and sent parts clean through the wing. It was not until a passengers repeated incestance that something was wrong did the F/E finally go back to look. The flight returned to IAD safely.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
David L
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 7:50 pm



Quoting EMBQA (Reply 4):

Sorry, not sure what your point is.
 
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HAWK21M
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 9:25 pm



Quoting EMBQA (Reply 1):
This was the third wing puncture event after a tire failure

The Earlier Incidents led to the Strengthening of the Tire to hold higher pressures.So its not that Nothing was done there.

The Luck factor did play a big role.A Chunk of Tire denting the wing & the resultant shockwave from the impact caused the Fuel panel to blow out & Snap a Wire above the MLG.This caused the spark to Ignite the fuel.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
David L
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 9:42 pm



Quoting David L (Reply 5):
Sorry, not sure what your point is.

OK, my fault - now that I've had more than 10 seconds to think about it.  Smile

Quoting EMBQA (Reply 4):
a flight taking off out of IAD had a tire fail and sent parts clean through the wing. It was not until a passengers repeated incestance that something was wrong did the F/E finally go back to look. The flight returned to IAD safely.

Sounds much like the previous Concorde incidents. I was thinking along these lines:

http://www.aviation-safety.net/database/record.php?id=19910711-0
http://www.aviation-safety.net/database/record.php?id=19860331-1
http://www.aircrash.org/burnelli/aw910722.htm

And none of these apparently involved running over a titanium blade at high speed and receiving a 2m chunk of tyre to the underside of the wing!

Quoting EMBQA (Reply 4):
incestance

A typo, I assume, not the game for all the family.  Smile
 
GDB
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 10:18 pm

The early incidents, as stated, led to a raft of modifications, mostly over the 1979-81 period.
They were not repeated, even with more extensive Concorde operations, by BA at least, in the following years.
 
Blackbird
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RE: The Impact Of FOD - Concorde Story

Sat Dec 22, 2007 10:59 pm

Didn't some fuel leak into the trim-tanks and put the CG too far aft also which contributed to the pitch-up?

Andrea Kent
 
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HAWK21M
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RE: The Impact Of FOD - Concorde Story

Mon Dec 24, 2007 7:07 am

The Pitch up was contributed by the Wing disentrigating & burning of the Flightcontrols on the Delta wing as the heat produced was to much.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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