Failure to turn off a malfunctioning air-conditioning system in time was found to be the reason behind an abnormal rise in temperature in the cockpit of a TransAsia Airways flight last year, which led to an emergency landing at the Taipei International Airport (Songshan airport), the Aviation Safety Council (ASC) said in its investigation report yesterday.
The council said that the passenger flight of the ATR-72 aircraft was scheduled to fly from Songshan airport to Kaohsiung International Airport on July 1 last year. The high temperature alarm went off after takeoff, which caused the pilots to request to return to Songshan airport. The aircraft landed safely.
The investigation found that both the temperature sensor and the temperature control device of the air-conditioning system on the left side of the aircraft were malfunctioning, which caused the heat to continue coming out of the draft. The pilots also failed to turn off the malfunctioning No. 1 air-conditioning system, which resulted in the persistent increase in temperature in the cockpit.
Investigators also found that the operation manual of the ATR aircraft, as well as that of TransAsia Airways, both failed to list the standards that should be used to differentiate different types of smoke in the cabin, nor did they identify the standard operating procedure that the pilots should follow when handling smoke from unidentified sources.
The airline also failed to indicate clearly in its pilot training that the pilots need to follow standard operating procedures when dealing with smoke of unidentified sources, the council said.
The airline informed the ASC in an e-mail dated Feb. 16 that it had amended the ATR Flight Crew Manual following the incident to tell pilots the standard operating procedures to follow when encountering smoke in the cabin.
The pilots will be trained and tested to follow the procedures, the airline added.