Mech, human factors in AirAsia crash
Indonesian investigators say a chronically faulty component and the crew’s attempts to fix the problem contributed to the crash of an AirAsia passenger aircraft last year, killing all 162 aboard.
December 31, 2015
By PLA Editor
Indonesian investigators say a chronically faulty component and the crew’s attempts to fix the problem contributed to the crash of an AirAsia passenger aircraft last year, killing all 162 aboard. Th e A320 aircraft crashed into the Java Sea less than halfway into a two-hour flight from the Indonesian city of Surabaya to Singapore in December 2014.
Th e report noted that the aircraft’s flight control computer had a cracked solder joint that malfunctioned repeatedly, including four times during the flight, and 23 times the previous year. “Subsequent flight crew action resulted in inability to control the aircraft … causing the aircraft to depart from the normal flight envelope and enter a prolonged stall condition that was beyond the capability of the flight crew to recover,” Indonesia’s national transport safety committee said in a statement today.
After the autopilot disengaged and the flight controls switched from the highly protective “normal law” to “alternate law”, the aircraft rolled to the left by 54 degrees – beyond the 45 degree angle considered to exceed normal parameters, deeming it an “upset”.
While attempting corrective action, the first officer pitched up to the point where stall warnings were triggered and the aircraft climbed to 38,000 feet at a low speed. As the aircraft stalled, the Indonesian-born captain told the French-born first officer him to “pull down” – a confusing instruction say aviation experts citing the standard, “pull up” and “push down”. Neither the captain nor first officer were native English speakers.