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Thread: Concorde trial
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Old 13th Mar 2012, 22:04
  #19 (permalink)  
fdr
 
Join Date: Jun 2001
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reverse logic

Back in the mid 60's the RAAF lost a P3B at Moffett from a failure of the MLG, the oleo falling away with wheel assy in the circuit. The aircraft burnt to a crisp on the subsequent landing, and fo compensation, Lockheed provided a replacement lower oleo. Quite a few years later, Lockheed added the rest of the aircraft above the oleo, one that had been a test bed and had many additional wiring looms still installed.

As the court contends that the titanium component caused the accident, then it should follow that had the tyre merely failed without impacting the Continental debris, as had frequently occurred with varying levels of consequential damage, then I presume it would be an Act of God, and the French legal system would have God in the dock. IMHO, the potential for catastrophic damage to occur with the Concorde design was not in any way undiscoverable, or unrecognised. What was not acted upon was the evidence to hand of a potential catastrophic failure mode, that could have been mitigated by engineering and in part by revised operational practices.

A tyre burst at high rotational speed is a fairly high energy event, and can cause extensive collateral damage, as it has been doing since the 50's when TO/LDG speeds started to become quite high. Tyres fail in service for various reasons, that may include external, environmental and operational factors as well as manufacture and maintenance errors. Tyres fail. Taxi a B747 too far, and the tyres will fail on TO, take off at Harare at high temps and weights, and the aft body gear tyres fail in the rotate regularly... tyres fail. If the certification authority, design engineers and operators, having a depth of incident data available were unable to recognise the risk, then that needs to be addressed. Had the tyre failed on this takeoff for no external causation, the outcome would have still been the same, as the inherent weakness of the design, and it's latent potential for consequential failures of some significance were not addressed.

Did the uncommanded shutdown of a engine still capable of producing thrust add to the mix? In most cases, that would be a major factor, for a VMCa event, however the compromising of the hydraulic system subsequent to the tyre impact and also the exposure to the fire from the fuel appears to have overtaken the normal course of events, and precipitated a failure of flight path control authority.

When the aircraft was designed, the design offsets for placing wiring and hydraulic components, fuel tank access panels, and hydraulic control lines are frozen on the basis of the knowledge available and hopefully sound consideration of the relative risks & costs. I would contend that in the 60's it was known that tyres can cause damage, that hydraulics at the rear of any body that has a fuel source can be burnt through, and that fuel leaks near ignition sources in a flow promoting aerosol/vaporisation of the fuel were foreseeable.

What probably has never been foreseeable is that replacing a poorly designed component subject to abrasion with a harder material would result in the chain of events cobbled together by fate in this disaster. Occasionally, accidents do happen. I would think that this one is very close to the AoG definition, than the outcome of an engineer sitting 5,000nm away from the event.
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