Posted on: 01 December 2015 by Mark Howells
The Komite Nasional Keselamatan Transportasi (KNKT) – Indonesia's National Transportation Safety Committee – has released its final report on the AirAsia Indonesia Airbus A320 aircraft, PK-AXC, which crashed into the Java Sea on 28 December 2014.
According to the KNKT, the cause of the accident was the result of a persisting issue with the aircraft’s Rudder Travel Limiter Unit (RTLU), which had a cracked solder joint. Problems with the RTLU had also been logged – and attended to in line with regulations – during November and early December 2014.
The committee said that during PK-AXC’s flight between Surabaya in Indonesia and Changi in Singapore, the flight crew reacted to the first three RTLU faults in accordance with Electronic Centralized Aircraft Monitoring (ECAM) messages, but that after the fourth fault the Flight Data Recorder (FDR) registered a different set of actions.
These actions included the resetting of the aircraft’s Flight Augmentation Computer Circuit Breakers (FAC CB), which resulted in electrical interruption to the FACs. This electrical interruption caused the autopilot to disengage, after which the pilot appears to have lost control of the aircraft.
The loss of control resulted in the aircraft departing from the normal flight envelope and entering a prolonged stall condition that was beyond the capability of the flight crew to recover, the KNKT concluded.
ttTony Fernandes, Group CEO of AirAsia, tweeted “These are scars that are left on me forever but I remain committed to making AirAsia the very best. We owe it to the families and my crew.”
The report says the FDR data did not show any indication of the weather condition affecting the aircraft.