Taiwan's aviation regulator said on Wednesday 10 of TransAsia's 49 ATR pilots have failed oral proficiency tests on handling an aircraft during engine failure following a fatal airline crash in the capital last week.
The 10 pilots will be suspended, the CAA said.
The tests were ordered after an ATR jet operated by TransAsia, the island's third-biggest carrier, crashed into a river in Taipei, killing at least 40 of the 58 on board. Initial data from the flight recorders indicate that the plane lost power in one engine just after take-off from Taipei's Songshan airport
Last week safety investigators speculated that the pilots of the twin-propeller plane might have reacted to a stalled-engine alarm by shutting down the wrong engine.
The crash has heightened concerns about the airline's safety record: last week's crash was its second fatal accident in seven months and the fifth time the airline had written off a plane.