The minutes before take off are routine. The flight is cleared for take-off at 16:42:17 local time on 25 July. Shortly before 16:44 flight AF4590 taxis onto the runway at Paris's Charles de Gaulle airport fully laden with 100 passengers and nine crew members.
Pilot Christian Marty throttles up the four Rolls-Royce/Snecma Olympus 593 turbojet engines and accelerates to the take-off speed of 220 knots.
As he begins the procedure, there are signs of trouble. Smoke appears around the two left-hand engines. One of them powers down - the second effectively cuts out completely. It is not clear whether the pilot has noticed - but it is already too late to abort take-off: There is no more runway.