the plane was unlikely to have suffered an in-flight break up or explosion, as the debris field would have been larger, and as a result, wreckage would have been discovered earlier. The flight recorders were recovered in August 2007, without which it would not have been possible to discover the cause of the accident. The National Transportation Safety Committee (NTSC, or KNKT as per its Indonesian name) described the near eight-month wait for the recovery of the flight recorders as "unacceptable". On 25 March 2008, the inquiry ruled that pilot error and a faulty navigation device were to blame. While cruising at , the pilots became preoccupied with troubleshooting the aircraft's two inertial reference systems (IRS), part of the navigation system. As they were correcting the problem, they accidentally disengaged the autopilot and failed to correct for a slow right roll even after a "bank angle" alarm sounded. By the time the pilots noticed the situation, the bank angle had reached 100° with almost 60° nose down attitude. Contrary to the correct recovery procedure, the pilots did not level the wings before trying to regain pitch control. The aircraft reached at the end of the recording, in excess of the aircraft's maximum operating speed (). The descent rate varied during the fatal dive, with a maximum recorded value of 53,760 feet per minute, roughly (). The tailplane suffered a structural failure 20 seconds prior to the end of the recording, at which time the investigators concluded the aircraft was in a "critically unrecoverable state". Both flight recorders ceased to function when the 737 broke up in mid-air at above sea level. The NTSC determined that: Flight crew coordination was less than effective, as the pilot in command (PIC) did not manage task sharing and crew resource management practices were not followed. The crew focused their attention on troubleshooting the Inertial Reference System (IRS) failure and neither pilot was flying the aircraft. After the autopilot disengaged and the aircraft exceeded 30 degrees right bank, the pilots appeared to have become spatially disoriented. The Adam Air syllabus of pilot training did not cover complete or partial IRS failure. The pilots had not received training in Aircraft upset recovery, including spatial disorientation. Maintenance concerns Investigators quickly became concerned about apparent poor maintenance and believed it might have been an important factor in the accident. Adam Air Adam Air's safety record, like that of