The pilots of AirAsia Bhd Flight 8501 cut power to a critical computer system that normally prevents planes from going out of control shortly before it plunged into the Java Sea, two people with knowledge of the investigation said. The action appears to have helped trigger the events of December 28, when the Airbus Group NV A320 climbed so abruptly that it lost lift and it began falling with warnings blaring in the cockpit, the people said. All 162 aboard were killed.