China Airlines Flight 006

Synopsis

On 19th Feb 1985, China Airlines Flight 006, a Boeing 747 aircraft, was flying from Taipei, Taiwan to Los Angeles, California, when the flight encountered jetstream turbulence, subsequently suffering lack of thrust in engine Number 4. The aircraft entered an uncontrollable descent from FL410 to 9500ft before the captain regained control and diverted to San Francisco. The landing was successful, and no lives were loss in this accident. The aircraft suffered significant structural damage due to excessive aerodynamic forces experienced during the descent.

In this accident, pilot error was the main contributing cause as he had been fixated with rectifying the loss of thrust of engine Number 4 at the wrong altitude, even though the 747 was more than capable of flying with 3 good engines. The pilot became too occupied with the loss of thrust and decreasing airspeed as the aircraft descend through the clouds. The captain later realized that the ADI showed excessive bank and pitch angle. The crew presumed that the indicators were faulty since such behavior was irregular and that there is no visual references. The crew became spatially disoriented (i.e. any discrepancies between visual, vestibular and sensory inputs resulting in a sensory mismatch (Melchor J. Antunano.; N.D). ) His actions caused the aircraft to enter a steep spiral dive till he regained control at 9500ft. It was also found that the pilot had insufficient rest and that his scheduled the week before this incident might caused him to have jetlag which also contributed to his inability to meticulously focus on important aspects of the flight that could have prevented the accident.

Although the captain finally disengage the autopilot to fly the plane manually, the plane was badly damaged as it diverted to San Francisco. If only the pilot had followed the standard operating procedure (SOP) in re-igniting engine 4 and control the rudder to compensate the loss of thrust of engine 4, the plane might not enter a steep dive at a high bank angle and caused injuries.