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Old 19th Jan 2008, 22:02
  #836 (permalink)  
sandbank
 
Join Date: Aug 2005
Location: Cardiff
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Malaysia Airlines 777 Perth?

Is there any parallel with the incident in 2005 involving a Malaysian Airlines 777-2H6ER (9M-MRG) ?

Climbing through FL380 rhe crew reported a low airspeed warning on the EICAS. Then instruments showed the aircraft was approaching the overspeed limit and the stall speed limit simultaneously.

The aircraft pitched up and climbed to FL410 and the indicated airspeed decreased from 270 kts to 158 kts. The stall warning and stick shaker devices also activated.

The captain disconnected the autopilot and lowered the nose of the aircraft. The autothrottle commanded an increase in thrust which the captain countered by manually moving the thrust levers to the idle position. The aircraft pitched up again and climbed 2,000 ft. Both left and right autopilots caused the aircraft to bank and the nose to pitch down, so the captain decided to fly the aircraft manually. During the approach, the aircraft warning system indicated a windshear condition but the crew continued the approach and landed the aircraft without further incident.

It was found that "An anomaly existed in the component software hierarchy that allowed inputs from a known faulty accelerometer to be processed by the ADIRU and used by the primary flight computer, autopilot and other aircraft systems".This hadn't been identified in the original testing and certification

The FAA issued an emergency AD to prevent the operational program software using data from failed sensors
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