The Indonesian accident investigstion board, KNKT, released the final report of their investigation into the January 1, 2007 accident of an AdamAir Boeing 737 in which all 102 occupants were killed.
They found that, during the flight from Surabaya to Manado, the Inertial Reference System (IRS) malfunctioned. Both pilots became engrossed with trouble shooting the IRS anomalies for at least the last 13 minutes of the flight, with minimal regard to other flight requirements. The pilots selected Attitude in the IRS, which disengaged the autopilot. After the autopilot disengaged and the aircraft rolled right and exceeded 35 degrees right bank, the pilots appeared to have become spatially disoriented. Control was lost and the airplane broke up and crashed into the sea.
1) Flight crew coordination was less than effective. The PIC did not manage the task sharing; crew resource management practices were not followed.
2) The crew focused their attention on trouble shooting the Inertial Reference System (IRS) failure and neither pilot was flying the aircraft.
3) After the autopilot disengaged and the aircraft exceeded 30 degrees right bank, the pilots appeared to have become spatially disoriented.
4) The AdamAir syllabus of pilot training did not cover complete or partial IRS failure.
5) The pilots had not received training in aircraft upset recovery, including spatial disorientation.
OTHER CAUSAL FACTORS:
1) At the time of the accident, AdamAir had not resolved the airworthiness problems with the IRS that had been reoccurring on their Boeing 737 fleet for more than 3 months.
2) The AdamAir maintenance engineering supervision and oversight was not effective and did not ensure that repetitive defects were rectified. (KNKT)