[TAIPEI] The crew of a crashed twin-propeller TransAsia plane faced a problem with one engine but restarted the other, investigators said on Friday, as it emerged the plane suffered a lack of thrust before crashing into a river in Taipei, killing 35 people.
The reason for the pilots' action was unclear but data showed a combined lack of thrust caused the almost-new turboprop ATR 72-600 to stall soon after take-off, Aviation Safety Council officials told a news briefing.
The plane, which can fly on one engine, was carrying 58 passengers and crew when it lurched nose-up between buildings, clipped an overpass and a taxi with one of its wings and then crashed upside down into a shallow river on Wednesday. Fifteen people survived.
The blackbox data and voice recorders showed that the plane warned five times of stalling before the crash in the centre of Taipei, according to preliminary findings by the council.
The right engine entered a state called "auto-feather", in which it reduced thrust to the propeller, Thomas Wang, managing director of the council, said.
The flight crew then reduced acceleration to the left engine, turned it off and then attempted to restart it, but it did not gain enough thrust.
Wang did not suggest a reason for the restart and stressed that a fuller report would be released later.
"The first engine experienced a problem 37 seconds after take-off at 1,200 feet," Mr Wang said.
He said the pilot had announced a "flameout", which can occur when fuel supply to an engine is interrupted or when there is faulty combustion, but there had not been one according to the data.
"The flight crew stepped on the accelerator of engine 2 (righthand side)... The engine was still operating, but neither engine produced power."
He said the aircraft could fly with one engine. The plane was powered by two Pratt & Whitney PW127M engines. Pratt & Whitney is part of United Technologies.
A fuller report on the crash will be available in next 30 days, with a final report expected in the next three to six months.
The pilot, 42-year-old Liao Chien-tsung, has been praised by Taipei's mayor for steering the plane between apartment blocks and commercial buildings before ditching the stalled aircraft in a river.
The bodies of Liao and his co-pilot were retrieved from the cockpit, with their legs badly broken, investigators said. "They were still trying to save this aircraft until the last minute," media quoted unidentified prosecutors involved in the crash investigation as saying.
Eight people are still missing. Aviation officials have said they have not given up hope of finding them.
The plane took off from Taipei's downtown Songshan airport and was bound for the Taiwan island of Kinmen. Among those on board were 31 tourists from China, mainly from the southwestern city of Xiamen.
Taiwan's aviation regulator has ordered TransAsia and Uni Air, a subsidiary of EVA Airways Corp, to conduct engine and fuel system checks on the remaining 22 ATR aircraft they still operate.
The crash was the latest in a string of Asian air disasters.
Indonesia has expanded its search for bodies of AirAsia Flight QZ8501 that crashed into the Java Sea in December, killing all 162 people on board.
After a lull in search and recovery efforts, more bodies and wreckage were found in the past few days off the coast of the Indonesian island of Sulawesi. A total of 96 bodies have been found.