JAKARTA, Indonesia -- A rudder-control system problem that had occurred nearly two dozen times in the previous 12 months, coupled with the pilots' response, led to last year's crash of an AirAsia plane in Indonesia that killed all 162 people on board, investigators said Tuesday.

In releasing their report, the country's National Transportation Safety Committee said an analysis of Flight 8501's data recorder showed the rudder-control system had sent warnings to the pilots during the Dec. 28 flight from the Indonesian city of Surabaya to Singapore.

The investigators said the fault was caused by cracked soldering on an electronic card.

Investigator Nurcahyo Utomo said the malfunction by itself should not have been dangerous. But after the fourth time an alarm went off during the flight, a crew member apparently went outside handbook recommendations and removed a circuit breaker to try to reset the system, he said. The autopilot then became disengaged, and the aircraft began to roll, but no movement was detected on the plane's manual control stick for nine seconds, he said.

It then began climbing rapidly before stalling and plummeting into the Java Sea.