TAIPEI (AFP) - The pilot of a passenger plane that crashed into a river in Taiwan killing 43 people, shut down the plane's only working engine after the other failed, a new report confirmed on Thursday.

TransAsia Airways Flight GE235 plunged shortly after take-off from Taipei's Songshan airport in February with 53 passengers and five crew on board. Only 15 people survived.

Seconds before the crash, the pilot said: "Wow, pulled back wrong throttle", the report from Taiwan's Aviation Safety Council revealed, from words recorded on a black box.

That led the plane's one working engine to fail after the other had already lost power, investigators said.

Dramatic car dashcam images showed the plane hitting an elevated road as it banked steeply away from buildings before crashing into the Keeling River.

Initial reports from the black boxes found the plane's right engine had "flamed out" about two minutes after take-off while the left engine was then shut down manually by the crew for unknown reasons.

Thursday's report confirmed that one engine had failed and was no longer delivering power to the aircraft.

One of the three pilots in the cockpit then pulled back the throttle of the other engine, the report said, causing it to also lose power.

Investigators said that with both engines shut off, the plane began a descent and was unable to recover.

"Why the pilot did this, we don't know. That's the main task for our (final) analysis report," said Thomas Wang, head of the aviation body.

The draft of that report is due out in November with the final report expected in April 2016.

Thursday's evidence was described as a "factual report" giving more detail about the crash, but not attributing responsibility or drawing final conclusions about the cause.

Taiwan's aviation regulator ordered TransAsia pilots to take an oral test on basic operating and emergency procedures for the French-made aircraft after the initial findings pointed to pilot error.