AD NUMBER: 2007-19-10
MANUFACTURER: Rolls Royce
SUBJECT: Airworthiness Directive 2007-19-10
SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) provided by an aviation authority of the United Kingdom (UK) to identify and correct an unsafe condition on Rolls-Royce plc RB211 Trent 500 series turbofan engines.

The MCAI states the following: This AD requires replacement of Intermediate Pressure Compressor (IP Compressor) Drums (Part Number FK30102) of ninepart serial numbers. This action is necessary following the discovery of strain induced porosity in a Trent 500 IP Compressor Drum forging.

Engineering assessment concluded that the problem is caused by the forging process and it is believed that this is a batch related occurrence. Nine discs, identified as coming from the same batch, could be affected by this problem.

Strain induced porosity in the dovetail posts of the stage 1 of the IP Compressor drum could result, inthe worst case, in an uncontained loss of 2 IP Compressor stage 1 blades. Thus, the strain induced porosity possibly affecting those nine discs presents a potential unsafe condition.

We are issuing this AD to prevent uncontained loss of IP compressor stage 1 blades.

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