Boac wrote:It could be argued that the spacer was 'crucial' since its absence is thought to have caused the a/c to depart the 'normal' take-off surface and encounter the metal which damaged the tyre, but wind played no part as far as I can see.
I would place the F/E's actions in unilaterally shutting down No2 high on the 'crucial' list since the a/c had little chance of reaching 3 engine safety speed.
Amongst the many 'what-if's' is could it have reached Le Bourget on 4 engines before the c of g became an insurmountable problem?
While I cannot argue with your comments about the No. 2 engine shutdown being one of the primary causes of this accident I am apt to question your comment about the wind. It might be argued that aircraft would have become airborne without or before encountering the object on the runway that precipitated the cascade of events that caused this aircraft to crash if the pilot had elected to note the wind, recalibrate and request a different take off direction/configuration. I would say that the wind speed is a definite part of the chain of causation here while accepting that ultimately the aircraft failed to reach 3 engine safety speed in the situation that developed here.
As to the No.2 engine question this paragraph forms part of the official report summary and notes the following:
The Concorde taking off from runway 26R at a speed of 175 kt ran over a strip of metal from a DC 10 which had taken off a few minutes before. This strip cut the tyre on wheel N¡ 2 of the left main landing gear, as part of a process that remains to be determined. One or more pieces of the tyre were thrown against the underside of the wing at the level of tank N¡ 5. This led to the rupture of the tank as part of a process, currently under study, which appears to associate the deformation of the tank wall and the propagation of the shock wave through the kerosene. A significant leak resulted from this. The escaping kerosene was whisked around in the turbulence around the landing gear and caught fire. The causes of the combustion are still being researched. Engines 1 and 2 then encountered severe problems, either through ingesting pieces of tyre or other pieces of the plane, or more likely through the kerosene leak itself and/or through the hot gases caused by the combustion of the kerosene. The aircraft took off with a very large stabilised flame that caused structural damage throughout the flight. The engine 2 fire alarm came on, and the crew announced shut down of this engine a few seconds later. The aircraft was flying at low speed and remained at a low altitude. The crew noticed that the landing gear would not retract, this non-retraction being explicable either by damage to circuits or systems following shocks resulting from the destruction of the tyre, or by exposure to flames. The crew mentioned a possible landing at Le Bourget aerodrome. The loss of power on engine 1 that occurred a few seconds later probably resulted from the ingestion of a mixture of hot gases/kerosene and internal damage caused by the previous ingestion. Aircraft angle of attack and bank then increased sharply, control of the aircraft was lost as a result of a combination of thrust asymmetry, due to profound thrust-drag imbalance and, perhaps to structural damage caused by fire. The thrust of engines 3 and 4 fell suddenly due to slipstream distortion. The aircraft crashed.
Obviously the inability to retract the undercarriage exacerbated the low energy/speed situation in which the crew found themselves in as well!
Caco
