Aircraft accident B737-400 Adam Air; Indonesia January 2007
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Aircraft accident B737-400 Adam Air; Indonesia January 2007
10 years have passed since the crash of an Adam Air Boeing 737-400 in Indonesia. The aircraft was in the cruise at FL350 in marginal VMC when it developed an IRS fault. The crew were preoccupied with the IRS malfunction for the last 13 minutes of the flight and subsequently lost control after one of the IRS was set to ATT. The aircraft reached 100deg bank,60 deg nose down and 3.5 g; it broke up at 490 knots in the dive. The aircraft had a history of 154 recurring defects directly and indirectly relating to the IRS between October and December 2006. All 96 passengers and 6 crew perished.
For brevity I have edited the following pertinent extract from the Boeing 737-300/400/500 Flight Crew Training Manual under heading Upset Recovery:
"A high bank angle is one beyond that necessary for normal flight. Though the bank angle for an upset has been defined as unintentionally more than 45 degrees, it is possible to experience angles of bank greater than 90 degrees. In high bank angle increasing airspeed situations, the primary objective is to maneuver the lift of the airplane to directly oppose the force of gravity by rolling in the shortest direction to wings level. Applying nose up elevator at bank angles above 60 degrees causes no appreciable change in pitch attitude and may exceed normal structure load limits as well as wing angle of attack for stall. The closer the lift vector is to vertical (wings level)m the more effective the applied g is in recovering the airplane.
A smooth application of up to full lateral control should provide enough roll control power to establish a very positive recovery roll rate.
If full roll control application is not satisfactory, it may be even necessary to apply some rudder in the direction of the desired roll.
Only a small amount of rudder is needed. Too much rudder applied to quickly or held too long may result of lateral and directional control or structural failure."
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In this accident it was evident the captain attempted to recover from the spiral dive by pulling back hard on the control column instead of first levelling the wings. Structural failure followed
On 25 March 2008, the inquiry ruled that pilot error and a faulty navigation device downed the airliner.[1][85] While cruising at 35,000 feet (10,668 m), the pilots became preoccupied with troubleshooting the aircraft's two inertial reference systems (IRS), part of the navigation system. The autopilot became disengaged and the pilots failed to correct for a slow right roll even after a "bank angle" alarm sounded. Despite the bank angle reaching 100° with almost 60° nose down attitude, the pilots did not level the wings before trying to regain pitch control. The aircraft reached 490 knots (910 km/h) at the end of the recording, in excess of the aircraft's maximum rated speed for a dive (400 knots (740 km/h)). The descent rate varied during the fatal dive, with a maximum recorded value of 53,760 feet per minute. The aircraft began to suffer small structural failures twenty 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 9,000 feet above sea level.[1]
The NTSC concluded that the causes of the accident were: 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 Adam Air 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
https://en.wikipedia.org/wiki/Adam_Air_Flight_574
Final Report:
https://reports.aviation-safety.net/...734_PK-KKW.pdf
For brevity I have edited the following pertinent extract from the Boeing 737-300/400/500 Flight Crew Training Manual under heading Upset Recovery:
"A high bank angle is one beyond that necessary for normal flight. Though the bank angle for an upset has been defined as unintentionally more than 45 degrees, it is possible to experience angles of bank greater than 90 degrees. In high bank angle increasing airspeed situations, the primary objective is to maneuver the lift of the airplane to directly oppose the force of gravity by rolling in the shortest direction to wings level. Applying nose up elevator at bank angles above 60 degrees causes no appreciable change in pitch attitude and may exceed normal structure load limits as well as wing angle of attack for stall. The closer the lift vector is to vertical (wings level)m the more effective the applied g is in recovering the airplane.
A smooth application of up to full lateral control should provide enough roll control power to establish a very positive recovery roll rate.
If full roll control application is not satisfactory, it may be even necessary to apply some rudder in the direction of the desired roll.
Only a small amount of rudder is needed. Too much rudder applied to quickly or held too long may result of lateral and directional control or structural failure."
............................................................ ............................................................ ............................................................ .............
In this accident it was evident the captain attempted to recover from the spiral dive by pulling back hard on the control column instead of first levelling the wings. Structural failure followed
On 25 March 2008, the inquiry ruled that pilot error and a faulty navigation device downed the airliner.[1][85] While cruising at 35,000 feet (10,668 m), the pilots became preoccupied with troubleshooting the aircraft's two inertial reference systems (IRS), part of the navigation system. The autopilot became disengaged and the pilots failed to correct for a slow right roll even after a "bank angle" alarm sounded. Despite the bank angle reaching 100° with almost 60° nose down attitude, the pilots did not level the wings before trying to regain pitch control. The aircraft reached 490 knots (910 km/h) at the end of the recording, in excess of the aircraft's maximum rated speed for a dive (400 knots (740 km/h)). The descent rate varied during the fatal dive, with a maximum recorded value of 53,760 feet per minute. The aircraft began to suffer small structural failures twenty 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 9,000 feet above sea level.[1]
The NTSC concluded that the causes of the accident were: 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 Adam Air 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
https://en.wikipedia.org/wiki/Adam_Air_Flight_574
Final Report:
https://reports.aviation-safety.net/...734_PK-KKW.pdf
Last edited by Centaurus; 15th Sep 2017 at 08:12.
