The European Aviation Safety Agency (EASA) yesterday withdrew requirements for repetitive Rolls-Royce Trent 900 inspections it mandated following the uncontained failure of a Qantas Airbus A380 engine last November. The relevant airworthiness directive (AD 2010-0242R1), which applies to all examples of seven engine variants, follows “further assessment of manufacturing data and additional stress analysis.”
Continued investigations support an initial “failure scenario” that an oil fire in the high-pressure/intermediate-pressure (HP/IP) structure air-buffer cavity led to rupture of the IP turbine-disc drive arm and subsequent disc over-speed and burst. The AD required inspections of the low-pressure turbine case drain, HP/IP cavity and oil service tubes to detect abnormal oil leakage. EASA noted that part of the reason for cancelling the requirements centered on its assessment that the “intrusive” inspections risked possible maintenance errors.
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