AD NUMBER: 2011-09-07

MANUFACTURER: Rolls-Royce plc (RR) RB211-524 Series and RB211 Trent 500, 700, and 800 Series Turbofan Engines
SUBJECT: Airworthiness Directive 2011-09-07

SUMMARY: 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:

During manufacture of a number of HP Compressor Stage 1 and 2 discs with axial dovetail slots, anomalies at the disc post corners have been found. Fatigue crack initiation and subsequent crack propagation at the disc post may result in release of two blades and the disc post. This may potentially be beyond the containment capabilities of the engine casings. Thus, these anomalies present at the disc posts constitute a potentially unsafe condition.

This AD has been issued to detect cracks in the high-pressure compressor (HPC) Stage 1 and 2 disc posts, which could result in failure of the disc post and release of HPC blades, release of uncontained engine debris, and damage to the airplane.

FMI: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/8A982ECACF650AF386257885004A52F7?OpenDocument