hcs_$reboot writes: The investigation took a year, but we finally know why Air Asia Flight QZ8501, en route to Singapore from the Indonesian city of Surabaya on December 28 last year, crashed into the Java Sea, killing all 162 people on board. The crash was caused by a combination of system malfunctions and improper pilot responses to cascading electrical and rudder-system problems. A cracked solder joint on the Airbus A320 resulted in an electrical interruption that caused computer-generated warnings of a rudder malfunction. The problem occurred four times during the flight. The first three times, the flight crew responded according to standard procedure, investigators said. The fourth time, however, the flight-data recorder indicated actions similar to those of circuit breakers being reset. That led the autopilot to disengage. Investigators said the crew was unable to react appropriately to "a prolonged stall condition," ending in the crash. The investigation points to weaknesses in pilot training in dealing with upsets, or when an aircraft is angled greater than 45 degrees.