Qantas has said it will conduct further, more
detailed one-off inspections of Rolls-Royce Trent 900 engines on
its Airbus A380 aircraft following the results of an additional
examination of components from the engine involved in the QF32
incident on 4 November.
The examination took place at the Rolls-Royce
facility in Derby, United Kingdom, and appears to provide a more
definitive explanation for the engine failure that occurred on
QF32. This resulted in a safety recommendation by the Australian
Transport and Safety Bureau (ATSB)
following discussions with Qantas, Rolls-Royce and the Civil
Aviation Safety Authority (CASA).
The ATSB's recommendation
is that these one-off inspections be conducted within two flight
cycles, which provides a level of inspection over and above the
current 20 cycle inspection required by the European Aviation
Safety Agency (EASA). The findings apply to all relevant variants
of the Rolls-Royce Trent 900 engine operated worldwide.
Qantas currently has two A380 aircraft in operational service,
following the grounding of the fleet on 4 November. Both A380
aircraft will be inspected at the Qantas Jet Base in Sydney.
Inspections commenced this afternoon (2/12/2010).
Qantas said it does not anticipate the inspections
to have an impact on international services.
The ATSB has described recent developments as
follows:
Recent examination of components removed from the
failed engine at the Rolls-Royce plc facility in Derby, United
Kingdom, have identified the presence of fatigue cracking within a
stub pipe that feeds oil into the High Pressure (HP) /
Intermediate Pressure (IP) bearing structure. While the analysis
of the engine failure is ongoing, it has been identified that the
leakage of oil into the HP/IP bearing structure buffer space (and
a subsequent oil fire within that area) was central to the engine
failure and IP turbine disc liberation event.
Further
examination of the cracked area has identified the axial
misalignment of an area of counter-boring within the inner
diameter of the stub pip; the misalignment having produced a localised thinning of the pipe wall on one side. The area of
fatigue cracking was associated with the area of pipe wall
thinning.
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