Date: 01 January, 2007
Operator: Adam Air
Flight number: 574
Aircraft type: Boeing 737-400
Location: Makassar Strait, Indonesia
Fatalities: 102 of 102
Relevant weather conditions: Thunderstorm
Accident type: Loss of control in-flight [LOC-I]
Primary causes: Pilot error, organisational failings
The following is a human factors analysis of the crash of Adam Air Flight 574; factual information of the sequence of events is drawn primarily from information provided by the National Transportation Safety Committee (20081).
Sequence of events
Initial course deviation
The first indication of trouble occurred when the aircraft began to deviate from its programmed route after entering storm clouds at around 40,000 ft about halfway into its flight; at the time, the aircraft was being navigated by using the data provided by the inertial reference system [IRS]. When the pilots became aware of this anomaly, they became engrossed in attempting to rectify it, which consumed a significant amount of time, during which the pilots paid little attention to the other instruments.
IRS mode change
The IRS mode selector was then changed into attitude mode by the pilots as they attempted to correct the situation. This caused several displays such as roll indication, and horizon and pitch scales to be lost; furthermore, the autopilot disengaged and the aircraft began to slowly roll to the right.
Failure to fly straight and level
While the aircraft's quick reference handbook [QRH] specified it was to be flown straight and level, but this was not done by either pilot and as the aircraft was flying through storm clouds, visual navigation was impossible.
Loss of situational awareness
It seemed by this time the pilots had almost completely lost situational awareness, and unfortunately, the pilots seemed to have also become spatially disorientated. At this point, with full autopilot control disabled by the pilots, the aircraft commenced a gradual right roll.
Bank angle increase
The pilots were alerted to the, by this point, considerable right bank angle, but only made minor corrective inputs which were insufficient to arrest the roll rate.
As the aircraft rolled further to the right the pilots realised that they were in an unsafe attitude but used incorrect control inputs to recover from the unusual attitude, literally flying their aircraft into the ocean.
The crew did not practice proper CRM in the areas of task sharing and communication and to a certain extent it eerily mirrored the fixation of the crew of Eastern Airlines flight 401 with their burnt-out gear indicator bulb.
Based on the analysis of the pilots' actions it seems much, if not all, of the blame can be laid on their shoulders. Previously, such a crash would likely have been written up as caused by 'pilot error', but while the crew did commit several errors, and allowed a rather benign situation to turn deadly, an in-depth analysis of Adam Air's operations can shed light on hidden errors that played perhaps an even greater part than the pilots. The investigation uncovered several faults on behalf of Adam Air, and one oversight by Indonesia's 'Directorate General Civil Aviation' [DGCA], that were significant factors in the accident.
Lack of managerial safety awareness
Pilot reports and maintenance records for the accident aircraft showed that for the three months prior to the accident, there were 154 defects related to the aircraft's IRS. In fact, just less than a year before the crash of flight 574, a similar fault occurred on another Adam Air 737, resulting in communications and navigation systems being lost. Flight 782's IRS malfunctioned and the pilots became lost, eventually landing almost 500 km away from their destination. Adam Air's management did not understand how the IRS worked, and did not appreciate the seriousness of the situation.
Lack of effective troubleshooting
There were no attempts by Adam Air's maintenance to actively troubleshoot the IRS', other than cleaning connections, swapping the units, and resetting circuit breakers. There were also no records of Adam Air's management condoning this blatantly inadequate maintenance practice; they should have been aware of these recurring defects and actively tried to solve the problem.
Poor DGCA oversight
Furthermore, DGCA was not performing its required task of overseeing the maintenance programme of Adam Air and ensuring the IRS defects were corrected.
Uncompleted CRM training
The captain had joined Adam Air six moths prior to the accident, on 6 July, 2006, and while he had undergone a line check and proficiency check on 22 July, he had not completed the required CRM training at the time of the accident. As mentioned previously, CRM failings were a significant causal factor in the accident.
Lack of training
Adam Air did not provide training on IRS failure, recovery from unusual attitudes, spatial disorientation, and unexpected autopilot disengagement.
Old QRHs and FCOMs
all of Adam Air's Boeing 737s were flying with out of date QRHs and flight crew operations manuals [FCOMs]. The latest revisions to these documents were made in 2004, which were even out of date when the aircraft were delivered to Adam Air in 2005. Pilots were given copies of web-based FCOMs and QRHs for training and personal reference, even though they were not to be used for the operation of aircraft in any way.
Perhaps an even more important factor is that the disregard of reasonable safety procedures in training and maintenance by Adam Air's management is an indication of the airline's culture, and their overall attitude towards safety. Prior to the crash, pilots had spoken out against the wilfully negligent management of Adam Air, with several resigning over poor navigation systems.
It is clear that Adam Air committed many latent errors through their poor maintenance and training systems, and these, combined with the active errors of the crew, were unfortunately enough to cost 102 lives.