Pilots of a Sudan Airways Airbus A310-300 which fatally overran after landing long at Khartoum had not realised that the aircraft was being subjected to a tailwind.
Thirty occupants were killed in the overrun as the aircraft, arriving from Damascus via Port Sudan at night, touched down 900m beyond the threshold of runway 36 and failed to stop.
During the approach, air traffic control had informed the crew of wind from 320k at 7kt.
But analysis of the flight-data recorder shows that the A310's ground speed of 155kt suggests it had actually been experiencing a 15kt tailwind.
It landed with some 2,080m of runway distance in which to stop. Although the runway was wet at the time the captain, flying, did not switch on the auto-brake.
The aircraft had been despatched with a deactivated left-hand thrust-reverser on its Pratt & Whitney PW4000 engines.
Sudan's Air Accident Investigation Central Directorate says that the captain selected reverse-thrust on both powerplants after touchdown. The aircraft began veering to the right and the crew disengaged the reversers about 9s later, using differential braking to guide it back to the centreline.
Twenty seconds after touchdown, with the jet still travelling at 109kt, the captain turned off the anti-skid system and braked fully. He also applied full reverse again, 12s later, but with minimal effect, and the aircraft overran at 76kt.
It came to a halt 215m off the runway end and caught fire on its starboard side. The inquiry believes the fire originated from fuel leakage between the engine nacelle and wing root, possibly the result of a tank puncture as the jet collided with lights and antenna structures.
Simulations of the accident carried out for the inquiry showed that, given the A310's stable approach, the required landing distance would have been sufficient under the wind condition transmitted by air traffic control.
At the time of the accident, on 10 June 2008, there were no indicators in the control tower for providing current wind velocity to arriving aircraft, says the inquiry, adding that the provision of weather data was "inadequate".
Investigators found that, during the roll-out, the aircraft's ground-proximity warning system repeatedly issued aural terrain warnings, and orders to "pull up", for which no explanation could be determined.
Twenty-nine passengers and a member of the cabin crew lost their lives in the blaze, and the investigation criticises the emergency response to the fire.
While the number of rescue vehicles was sufficient, says the inquiry, there was an "acute shortage" of fire-fighting personnel.
"Due to the rough and sandy surface around the crash site and lack of exit routes, the response time was not in accordance with the standard," it says, adding that no means of communication was available between the vehicles and the fire station.
Participation of civil defence fire vehicles "impaired" the efficiency of the airport's emergency response, the inquiry found, while transfers of qualified personnel meant the leader of the operation had "little experience" in dealing with such an accident.
"The investigation revealed that the fire could not be fought by the airport fire department with the required rapidity and efficiency," it states.
Heavy smoke in the cabin hampered the evacuation of the A310. Most of the 203 passengers and 11 crew members escaped from the aircraft through the forward left-hand exit. None of the right-hand exits were used, owing to the fire, while the left rear door was opened but its slide was not deployed.
"Passengers were not briefed on safety measures before and during the trip," the investigation says, and adds: "Hand luggage delayed the evacuation process."
Source: Air Transport Intelligence news
