The Australian Transport Safety Bureau (ATSB) has found that low quality engine oil feed pipes caused the uncontained engine failure in...
The Australian Transport Safety Bureau (ATSB) has found that low quality engine oil feed pipes caused the uncontained engine failure involving a Qantas Airbus A380 jumbo jet over Batam Island, Indonesia on 4 November 2010.
ATSB found that a number of oil feed stub pipes within the High Pressure / Intermediate pressure (HP/IP) hub assembly were manufactured with thin wall sections that did not conform to the design specifications. These non-conforming pipes were fitted to Trent 900 engines, including the No. 2 engine on VH-OQA. The thin wall section significantly reduced the life of the oil feed stub pipe on the No. 2 engine so that a fatigue crack developed, ultimately releasing oil during the flight that resulted in an internal oil fire. That fire led to the separation of the intermediate pressure turbine disc from the drive shaft. The disc accelerated and burst with sufficient force that the engine structure could not contain it, releasing high-energy debris.
Engine maker Rolls Royce said the oil pipe was one of a small number which had been incorrectly manufactured as a result of a measurement error during a precision drilling procedure.
Following the incident, and in parallel with the ATSB's investigation, Rolls-Royce carried out its own detailed investigations to understand and address the chain of events which led to faulty oil pipes being released into service. A number of issues were identified and changes implemented to address them, including:
*.Royce released an engine control software update that included an IP turbine over speed protection system (IPTOS) that is designed to shut the engine down before the turbine disc can over speed, in the unlikely event that a similar failure occurs..
*.Better quality assurance processes with supporting training.
*.Revised analysis of the likely effects on an engine in the event of a component failure.
*.Improved manufacturing and design procedures.
Uncontained disc failures are extremely uncommon. Before the 4 November 2010 incident, the last such failure on a Rolls-Royce large civil engine occurred in 1994 since when the fleet has accumulated more than 170 million engine flying hours.
