AD NUMBER: 2009-04-13
MANUFACTURER: Rolls Royce
SUBJECT: Airworthiness Directive 2009-04-13
SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product.

The MCAI describes the unsafe condition as: 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.

We are issuing this AD to prevent uncontained failure of the LP compressor (fan) disc assembly and damage to the airplane.

FMI: www.faa.gov/regulations_policies/airworthiness_directives/