TransAsia pilots who operate the type of plane involved in Wednesday's deadly crash began proficiency tests Saturday as investigators looked at pilot error as a factor in the crash.
TransAsia cancelled 90 flights over the next three days to allow its 71 ATR pilots to be retested as required by Taiwan's Civil Aeronautics Administration.
The plane crash killed at least 40 people; another 15 were rescued alive. Teams are searching the Keelung River for the three people who remain missing.
Investigators said Friday that the two turboprop engines failed to provide enough thrust to lift the ATR 72-600 aircraft, sending it into the river shortly after takeoff from Songshan Airport in Taipei Wednesday morning.
Officials from Taiwan's Aviation Safety Council said at a news conference on Friday that voice and data recorders revealed the right engine failed 37 seconds after takeoff. One of the pilots then shut down the left engine, likely by mistake, and tried a restart. But the plane crashed before the pilots could restart the engine. A recording of air traffic controllers indicated the pilot's last words before the plane went down were "Mayday, mayday, engine flameout."
It was still too early in the investigation to determine the cause of the engine failure, officials said Friday.
Internet video showed the plane's left wing perpendicular to the ground, clipping an elevated highway and a taxi cab before crashing into the river.
It is the second ATR-72 to crash in Taiwan in as many years. Last July, one of the French-made twin-engine turboprops crashed during poor weather near the airport on the island of Penghu, killing 48 people.