The Wear Strip From Someone Else's Airplane

On 9 July 2000 at Houston, a Continental Airlines technician replaced the lower left wear strip on the fan reverser cowl of a DC-10's number 3 engine. The replacement was improvised: the cowl support ended up drilled with thirty-seven holes where the installation requires only twelve, the part was made of titanium alloy with a mastic not normally used for the operation, and the adjacent strip was left too long — the BEA found the strip had neither been manufactured nor installed in accordance with the manufacturer's procedures. Sixteen days later that DC-10 took off from Paris Charles de Gaulle, five minutes ahead of Air France Concorde F-BTSC, and the strip fell onto runway 26R. At takeoff power, shortly before rotation, the Concorde's front right tire on the left gear ran over the 435-millimeter metal strip and burst; heavy tire debris struck the wing and ruptured fuel tank 5; the leak ignited into a massive fire under the left wing. Unable to climb or accelerate, the Concorde crashed onto a hotel at Gonesse less than two minutes later. 109 aboard and 4 people on the ground died.

This card breaks the walls of the hangar: the maintenance error was on ANOTHER OPERATOR'S AIRCRAFT. The mechanic who freehand-drilled a cowl in Houston never imagined his work product lying on a Paris runway in front of the world's fastest airliner. Every nonconforming part is a projectile-in-waiting on a shared runway system — your approved data discipline protects people who will never fly your airplane. It is the corpus's ultimate argument for making parts to the drawing, only to the drawing.

1. Fabricate replacement parts only from approved data — material, dimensions and finish per the manufacturer's specification, never by copying the worn part "close enough".
2. Install per the documented procedure: hole patterns, fastening and sealants are part of the design, not preferences.
3. If the approved part or data is not available, ground the discrepancy through engineering — an improvised part is an unapproved part.
4. Inspect the installation against the drawing before closing the cowl, and treat anything protruding or misfitted on cowlings as a FOD hazard to every aircraft behind you.
5. Remember the runway is shared: what falls off your aircraft becomes the next crew's emergency.

Frequency of nonconforming fabricated-on-the-spot parts is not quantified in public sources; the BEA documented this strip's manufacture and installation outside procedures in detail, and fitting of wrong parts sits high in the recurring maintenance-occurrence canon (UK CAA CAP 716, Table 2).

Tire burst at takeoff power; rupture of tank 5 by debris; a major fire under the left wing; loss of thrust on engines 1 and 2; the aircraft could neither climb nor accelerate and crashed onto a hotel at La Patte d'Oie, Gonesse. All 109 aboard — 100 passengers and 9 crew — and 4 people on the ground were killed; the Concorde fleet was grounded and the type's career effectively ended (BEA final report f-sc000725a).