The debris from the CO DC-10 that departed CDG minutes before AF #4590 was certainly a "but for" cause of the Concorde crash. In other words, without the metal strip, the whole chain of events would have never started. However, I am convinced that a much more significant and proximate cause of the crash was human error. To this end, The Observer article "Doomed" by David Rose is a must read. His conclusion: "Men, not God, caused Concorde to crash, and their omissions and errors may have turned an escapable mishap to catastrophe." More specifically, the confluence of the following errors and omissions caused the crash:

(1) Air France's poor maintenance in failing to replace a spacer on the landing gear (this resulted in Concorde drifting off center as it hurtled down the runway, possibly causing the ingestion of runway lights into one or more engines and also contributing to number two below because the plane was on a collision course with another AF plane carrying Jacques Chirac);

(2) A load in excess of the permissible maximum takeoff weight (MTOW) (coupled with a takeoff with a tailwind);

(3) Premature rotation with insufficient airspeed to avoid a stall; and

(4) The shutting down of the number two engine by the understandably harried flight engineer after takeoff, an engine that was still producing critical thrust.

With regard to the civil lawsuit that has been filed in Houston, I cannot envision CO or Goodyear being held liable. An essential element of negligence is foreseeability, and I don't know how either party could have foreseen that a tiny strip of metal would have fallen from a departing airplane, coming to rest on a runway where it would slice through another airplane's tire, causing a fatal loss of control.