Saturday, February 7, 2015

The death toll from Wednesday’s plane crash in Taipei, Taiwan reached 40 today with the recovery of five more bodies.

There were 58 on board when TransAsia Airways Flight 235 crashed into the city’s Keelung River. Fifteen survived and three more remain missing. Tzu Chi Foundation volunteer Lee Hung Shu-ying said today cold weather meant the families of the missing believe their loved ones are dead.

The Aviation Safety Council is investigating. The plane was in the air for minutes before banking steeply, hitting an elevated road, and crashing into the river. The domestic flight from Taipei Songshan Airport was headed to the island of Kinmen.

Investigators are focusing on the ATR 72-600’s engines. One engine automatically ‘feathered’ itself. Feathering involves the turboprop’s propeller rotating its blades to reduce drag.

Engines autofeather when they fail (‘flaming out’). By reducing drag on the non-working engine, a twin turboprop plane can fly safely using only its other engine. A feathered engine will not provide any thrust. The reason for autofeathering is presently unclear; what is known is the flight crew subsequently shut off the wrong engine. A series of stall warnings went off in the cockpit as the aircraft headed to disaster.

Aviation Safety Council managing director Thomas Wang confirmed an automated “number two engine flameout” message should have alerted the crew to the engine trouble, leading them to follow “the corresponding checklist”. “There are procedures that pilots go through — safeguards — when you’re going to shut down an engine, particularly close to the ground,” said John M. Cox, former commercial pilot and boss of a safety consultant. “Why that didn’t occur here, I don’t know.”

Stephen Fredrick, a former pilot of similar aircraft, told CNN video showing the final seconds is consistent with dual flameout. He said the wings-level, nose-down position suggested gliding.

Wang, however, cautions it is too early to blame any particular factor. “At this moment we just release the numbers, the parameter we’ve confirmed, we did not release any judgment who did what at this time”. The Aviation Safety Council has teamed up with engine manufacturer Pratt & Whitney Canada to examine the engines.

Also being prioritised is finalising a cockpit voice recorder transcript and cockpit examination. The aircraft was near-new.

Local prosecutors are investigating potential “professional error”, and the Civil Aeronautics Administration has ordered TransAsia retest all ATR pilots. 90 flights over three days are cancelled to allow the proficiency checks. TransAsia and Uni Air have also been ordered to check their collective 22 ATRs for engine and fuel system problems.

Pilot Liao Chien-tsung and his co-pilot, not publicly identified, were initially hailed as heroes by prosecutors, mayor Ko Wen-je, international press, and at least one relative of a survivor. After declaring “Mayday Mayday, engine flameout” to air traffic control the pair grappled with their struggling plane, avoiding buildings in its path.

They have been credited with reducing the death toll. Their bodies were found in the cockpit, with leg fractures. Both were still holding the wrecked plane’s controls.