Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by another country to identify and correct an unsafe condition on Rolls-Royce Deutschland Ltd & Co KG, BR700-715A1-30, BR700-715B1-30, and BR700-715C1-30 turbofan engines. The MCAI states the following:
The application of most recent 3D FEM modeling has resulted in the need to reconsider the disc lives as currently shown in the Time Limits Manual. The current Post Certification Life Statement for the low pressure (LP) compressor (fan) disc assembly revises the Declared Safe Cyclic Life (DSCL) from 33,000 flight cycles to 25,000 flight cycles for both the BR715 LP (fan) disc assembly Part No. (P/ N) BRH10048 and BR715 LP compressor (fan) disc assembly P/N BRH19253, when installed in the BR700-715A1-30 engine model and operated against the Hawaiian Flight Mission.
The proposed AD would require revising the maximum approved life limit for both the BR715 LP compressor (fan) disc assembly P/N BRH10048 and BR715 LP compressor (fan) disc assembly P/N BRH19253, from 33,000 flight cycles to 25,000 flight cycles, if ever operated against the Hawaiian Flight Mission and removing LP compressor (fan) disc assemblies from service that exceed the maximum approved life limit before further flight. This condition, if not corrected, could result in uncontained failure of the LP compressor (fan) disc assembly and damage to the airplane.