While cruising at flight level 390 (FL390) the number 1 engine failed. The crew made a PAN call to air traffic control (ATC) advising of the problem and requesting descent. A descent clearance was issued and the aircraft was given a direct track for final approach to runway 34L. An alert phase was declared by ATC. The pilot subsequently advised that no emergency existed and that a normal approach and landing was expected. As a precaution, emergency services were placed on a local standby. The aircraft subsequently landed safely.
An inspection of the engine by the operator found that both the high and low-pressure rotating assemblies were seized, and that there was light metal contamination on the chip detector. After removing and dismantling the engine, it was determined that the number 4 bearing had failed. The operator reported that the bearing had been in service for 21,004 hours since new, and 10,128 hours since the last visual inspection of that component. The chip detector had been inspected about 25 hours prior to the failure and found clean.
There have been two other similar reported failures in Australia. The engine manufacturer has reported that an improved bearing will be available shortly. The operator plans to review chip detector inspection periods in the interim.
The Bureau of Air Safety Investigation is currently investigating the underlying factors associated with number 4 bearing failures in CFM-56 engines.
Any recommendation issued as a result of this investigation will be published in the Bureau's Quarterly Safety Deficiency Report.
|Date:||18 March 1999||Investigation status:||Completed|
|Time:||1522 hours ESuT|
|Location:||150 km SW Sydney, Aero.|
|State:||New South Wales|
|Release date:||08 September 1999||Occurrence category:||Incident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Airbus Industrie|
|Type of operation||Air Transport High Capacity|
|Damage to aircraft||Nil|
|Departure point||Melbourne, VIC|
|Departure time||1542 hours ESuT|