An interim ATSB investigation report has confirmed the sequence
of events that led to the 4 November 2010 uncontained engine
failure on board a Qantas A380 aircraft over Batam Island,
Indonesia.
The report also sets out how, as a result of the investigation
to date, Rolls-Royce, affected airlines and safety regulators have
taken action to ensure the continued safe operation of A380
aircraft.
Released today, the report highlights how the intermediate
pressure turbine disc in the aircraft's No. 2 engine had been
weakened by an oil fire. As a result, the disc separated from its
shaft, increased its rotation speed and broke into several parts.
Sections of the fractured disc and other engine components
penetrated the aircraft's left wing and a number of other areas on
the aircraft, resulting in significant structural and systems
damage.
The oil fire that weakened the disc was due to a manufacturing
defect in an oil feed pipe. That defect resulted in fatigue
cracking in the pipe, so that oil sprayed into an engine cavity
where it ignited because of the high air temperature.
The report also shows how some of the extensive flight data
recovered in the first stage of the investigation has been used to
program a simulation of how the aircraft handled following the
accident. This has helped investigators to understand better the
aircraft's handling and performance.
The simulation was part of a broader exercise to understand the
extent and consequences of the airframe and systems damage to the
aircraft and the consequences for flight crew workload. The
findings from this continuing work will provide valuable safety
lessons for future operations.
The ATSB will continue to work with international safety
agencies and other organisations to gather and compile the large
amount of complex factual information required to complete the
investigation. Included in this work will be:
- testing and analysing the black-coloured soot residue found in
the left wing fuel tank - analysing the flight simulation test data
- continuing to review the quality control and quality assurance
system affecting the engine design and manufacturing process - reviewing the aircraft's maintenance, including engine workshop
visits.
The aircraft is currently in Singapore awaiting repair.
Given the highly complex nature of this investigation, the final
ATSB report is expected to be released in May 2012.
A copy of the interim factual report is available at AO-2010-089