The Taiwan government ordered all airlines to review safety protocols on Wednesday after nearly half of the pilots trained to fly TransAsia's ATR twin-engined aircraft were suspended following last week's fatal crash in the capital.
Taiwan's aviation regulator said 10 of TransAsia's 49 ATR pilots had failed oral proficiency tests on handling the aircraft during engine failure. A further 19 pilots did not take the test, due to either sickness or because they were not in Taiwan, the Civil Aviation Authority (CAA) said.
The 29 pilots who failed or did not take the test have been suspended, the CAA said.
"The result is not acceptable for us," TransAsia chief executive Peter Chen told a news conference. "We will definitely strengthen their training."
Authorities ordered the tests after one of the airline's ATR 72-600s crashed into a river in Taipei killing at least 42 of the 58 on board.
TransAsia Flight GE235 lurched between buildings, clipped an overpass with one of its wings and crashed upside down into shallow water shortly after taking off from a downtown Taipei airport last Wednesday.
Initial data indicates that the plane lost power in one engine after take-off from Taipei's Songshan airport.
Officials in Taiwan and industry analysts have said evidence presented so far raises questions over whether the pilots may have accidentally cut the wrong engine.
"The lunar Chinese new year holiday is coming... We'll ask every local airline to check their flight safety," said Chen Jian-Yu, minister of Transportations and Communications.
This was the second TransAsia ATR crash in seven months, and the fifth crash involving the airline since 1995, raising questions about safety standards at Taiwan's third largest carrier.
Initial data from the flight recorders indicate the plane lost power in one of its engine just after lifting off, Taiwan's Aviation Safety Council (ASC) said on Friday.
The crew then shut down the other engine, which was working, and attempted to restart it shortly before the aircraft crashed.
Commercial aircraft can fly with just one working engine, and the authorities have not released any information from the recorders that indicates why the pilots shut down the working engine.
They said on Friday, however, that a combined loss of thrust caused the almost new aircraft to stall soon after take-off.
