The European Aviation Safety Agency (EASA) issued an airworthiness directive (AD) effective Nov. 10 mandating new inspection requirements for Rolls-Royce Trent 900 engines powering Airbus A380s. The action was taken after an uncontained engine failure on a Trent 900 powering a Qantas A380 on Nov. 4. Since then, several oil problems on Trent 900s have been found by operators.

The EASA directive states that “An uncontained engine failure has recently occurred on a Rolls-Royce Trent 900 involving release of high energy debris and leading to damage to the aeroplane.

“Analysis of the preliminary elements from the incident investigation shows that an oil fire in the HP/IP [high pressure/intermediate pressure] structure cavity may have caused the failure of the Intermediate Pressure Turbine (IPT) Disc.

“This condition, if not detected, could ultimately result in uncontained engine failure potentially leading to damage to the aeroplane and hazards to persons or property on the ground.

“For the reasons described above and pending conclusion of the incident investigation, this AD requires repetitive inspections of the Low Pressure Turbine (LPT) stage 1 blades and case drain, HP/IP structure air buffer cavity and oil service tubes in order to detect any abnormal oil leakage, and if any discrepancy is found, to prohibit further engine operation.

“The requirements of this AD are considered as interim action. If, as a result of the on-going incident investigation, a terminating action is later identified, further mandatory actions might be considered.”

As a result, the regulator is requiring operators to carry out extended ground idle runs, inspections of the low-pressure turbine stage 1 blades and case drain, and inspection of the high pressure and intermediate pressure structure air buffer cavity and oil service tubes.

If a problem is found, “any further engine operation is prohibited,” EASA says.

For on-wing engines, inspections are required within 10 flight cycles of the AD taking effect, and then at intervals of no more than 20 flight cycles. For in-shop powerplants, the inspection requirement is after an engine test procedure and before the next flight.

In addition to Qantas, which has its A380s grounded, Singapore and Lufthansa are changing some of their Trent 900s, although the latter says it is unrelated to the Qantas problem.