Indecision and Changing One's Mind

The flight crew of the Air France jet that overran the runway at Toronto "lost" 12 seconds in deciding if they should go-around (the copilot's wish) or continue the landing (captain's final decision), according to an account in the French newspaper Le Figaro. The airplane landed some 4,800 feet down the runway (see ASW, Aug. 8). It took the airplane a further 12 seconds to start slowing down (e.g., about 2,200 feet), which might include the 4 seconds to get the nose gear on the ground, 4 seconds hesitating (or discussing the possibility of a go-around), and perhaps another 4 seconds for the thrust reversers to actually start having an effect in slowing the airplane's speed.

The Le Figaro source assumes that these 4 seconds were due to the hesitation between the pilot and copilot, which both deny. The cockpit voice recording (CVR), when released, should tell the story.

The Le Figaro report does not say that human error is the major cause of the accident, it just adds it to a series of factors (wet runway, false indication of ATC- reported wind velocity due to an equipment hit by lightning, wind gusts, lack of visibility, etc.). The accident is in many respects a recast replay of the Qantas Flight QF1 overrun at Bangkok (see ASW, April 1, 2002). In that landing accident, the captain's decision to direct the copilot to go-around was then ineptly and injudiciously overridden after touchdown by the captain, once he'd assumed control. Recall from the report of investigation into that accident: "The auto-brake system was disarmed automatically because the number 1 [engine] thrust lever was left advanced for more than three seconds, with the main wheels on the ground. The crew did not notice that the brakes had been disarmed." As a consequence, the aircraft rolled off the end of the runway.