Air France is backing Canadian investigators' recommendations to give pilots better guidance and training for conducting landings in stormy weather, following the 2 August 2005 overrun of an Airbus A340-300 at Toronto Pearson Airport.
Transportation Safety Board of Canada found the crew of flight AF358, arriving in a severe thunderstorm, did not calculate a margin for error for the landing. The "rapidly-changing" situation led to a "diminishing awareness", it says, about the amount of runway available, and poor visibility meant the pilots could not see the runway end until very close.
It says standards should be established to limit approaches and landings during storms. The TSB also says pilots should be trained to make accurate estimates of the margin between landing distances available and those required before conducting approaches in deteriorating conditions.
The TSB's chief investigator into the accident, Real Levasseur, says crews should be made fully aware of the distance an aircraft needs to land in different conditions: "Information is available to pilots. However, an unstable situation is no time to leaf through manuals."
As the A340 approached runway 24L, at a height of about 200ft (61m), the wind veered from a headwind to a tailwind component causing the jet to deviate above the glideslope. It crossed the threshold at 70-80ft, some 40ft higher than normal, then entered a heavy rain shower which severely limited the crew's visibility.
Web graphic to show sequence of events in Air France A340 overrun at TorontoLightning ahead persuaded the crew that landing would be safer than a go-around. But the A340 touched down around 1,160m along 24L at 143kt indicated air speed (IAS) (274km/h), leaving 1,620m in which to stop. High workload maintaining directional control resulted in idle-reverse thrust selection being delayed for 12.8s, and full reverse for 16.4s.
"It is clear the pilots were aware of the landing distance available for runway 24L," says the TSB's inquiry report. "There is no indication they had calculated the landing distances required for the arrival, nor are there any direct and specific Air France procedures that would require such calculations."
By the time full reverse thrust engaged, the aircraft was still travelling at 107kt with less than 370m of runway remaining. It left the end of 24L at over 80kt, coming to rest after about 300m.
Air France says it has already made several adjustments to its procedures and training.