Malaysian Airliner suffered engine failure and hard landing at Heathrow

The Department of Transport’s Air Accident Investigation Branch (AAIB) has reported that signifiacnt vibration of the Boeing 747-4H6’s (9M-MPL) second engine was noted during departure from London Heathrow Airport on August 17, 2012.

“The engine subsequently failed and was shut down by the crew who elected to jettison fuel and return to Heathrow Airport.

“During the approach for a planned autoland, all three autopilots disengaged, the cockpit displays and lights flickered and a series of fault messages were displayed.

“The resulting electrical failures culminated in a loss of power to one of the electrical AC buses, and many of the systems powered by this bus were lost or degraded.

“The commander continued the approach, manually flying the aircraft to a safe landing,” accroding to the report.

An investigation by the AAIB determined that flickering cockpit displays and lights resulted from a series of failures within the aircraft electrical system.

This was caused by a latent mechanical failure in a ‘Bus Tie Breaker.’

“The effect of this latent failure only became apparent when the aircraft electrical system automatically reconfigured for the planned autoland,” says the AAIB.