The Australian Transport Safety Bureau (ATSB) has called on airworthiness authorities to review the findings of its final report on the QF32 accident and possibly tighten cerification standards around uncontained engine failures.
The accident involved a Qantas Airways Airbus A380, registered VH-OQA, which suffered an uncontained engine failure on its number 2 Rolls-Royce Trent 900 engine shortly after takeoff from Singapore Changi airport on 1 November 2010.
In an interim report released in January 2012, the ATSB had found that the uncontained engine rotor failure originated from a fatigue crack in oil feed stub pipes in the high pressure/intermediate pressure (HP/IP) hub assembly.
The crack resulted in oil being released into the HP/IP section of the engine, sparking a fire that led to the separation of the intermediate pressure turbine disc from the drive shaft. That resulted in high-energy debris being ejected from the engine nacelle, damaging the aircraft.
The ATSB report says that this included significant damage to the number 2 engine pylon and thrust links, left wing box structure and fuselage butt-straps. Minor damage was also sustained by the fuselage.
"The damage to the aircraft itself is more extensive than would have been predicted by the models currently used to guide the certification of aircraft and particularly how they plan to deal with the potential consequences of an engine failure of this sort," says ATSB chief commissioner Martin Dolan.
In its report, the ATSB says that it "has issued a safety recommendation to the United States Federal Aviation Administration and the European Aviation Safety Agency to review and incorporate any lessons learned from this accident into their aircraft certification advisory material regarding the minimisation of the hazards from uncontained engine rotor failures."
Part of the investigation also looked at the workload of the crew during the emergency, including whether the electronic centralised aircraft monitor system made it difficult for them to control the situation.
However, Dolan says that the ATSB is "satisfied that... it was manageable by flight crew, as was in fact evidenced."
The final report also confirmed earlier findings that deficiencies in R-R's quality control systems led to the oil feed stub pipe being installed on the engine despite it not conforming to design specifications. As a result of that, the ATSB had issued several safety recommendations to R-R in December 2010 which it says have now been addressed.
"The lessons learned and the subsequent procedural changes have been applied broadly to the Rolls-Royce operations and the ATSB is satisfied that the steps taken by Rolls-Royce address the issues identified in the course of our investigation," says ATSB chief commissioner Martin Dolan.
R-R director engineering and technology Colin Smith admitted in a statement that the manufacturer "clearly fell short" of its high standards for safety, quality and reliability.
"We support the ATSB's conclusions and, as the report notes, have already applied the lessons learned throughout our engineering, manufacturing and quality assurance procedures to prevent this type of event from happening again," he adds.
Source: Air Transport Intelligence news
