Taiwan's civil aviation regulator is testing pilots from TransAsia Airways, which lost one of its planes in a fatal crash last week, on how they handle an engine failure, which is seen as the reason behind the accident.
Taiwan's Aviation Safety Council (ASC) had said on Friday the plane's blackbox had shown that one of the plane's engines had lost power just after taking off, and the pilots switched off the second one in a bid to restart it.
This move by the pilots has come under scrutiny, given that the aircraft could have been flown even on one engine.
With both engines losing power, the plane lost thrust and stalled within minutes of take-off, and the pilots veered it past residential buildings into a lake, leaving 40 dead.
Taiwan's Civil Aviation Authority is now testing 71 ATR pilots from TransAsia Airways to see how they would handle a similar situation, after the cockpit voice recorder and the flight data recorder revealed moments of chaos and confusion, as the pilot sent out a "Mayday" call.
According to ASC, a master warning had signalled that one engine had lost power at 10:52:38 a.m. (local time) on 4 February as the plane was reaching 1,200 feet in altitude after taking off.
The second engine of the two-engine plane was still operating normally at that point.
However, the pilots cut off power to the functioning engine off at 10:53:24 am for unknown reasons, the plane's flight data recorder has revealed.
According to the cockpit voice recorder (CVR), the crew had discussed restarting the second engine just four seconds after the master warning for the other engine had gone off, according to Focus Taiwan News Channel.
"There must have been something wrong with what the crew did. "It's a very big deal to turn off one engine after take- off. It needs to be double checked by the crew," a Civil Aviation Authority (CAA) official told Reuters.
The test results will be out on Wednesday, officials said.
The death toll from the crash remained at 40 on Monday, with three people still missing.