AD NUMBER: 2010-02-08

MANUFACTURER: Turbomeca Turmo IV A and IV C Turboshaft Engines
SUBJECT: Airworthiness Directive 2010-02-08

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 a maintenance inspection before the first flight of the day, an oil leak was found on an engine deck. A circumferential crack on the intermediate bearing return flexible pipe union (pipe part number 9 560 17 606 0) was identified as the origin of the leak. A similar oil pipe union crack was then reported at the same location on another engine, on the same pipe part number. This pipe part number was approved as Modification TU 233 in 2008. Although such cracks have been detected and did not lead to an in-service event, the possibility exists that some additional cracks could occur and may not be detected before the potential complete rupture of the union.

We are issuing this AD to prevent a helicopter engine in-flight shutdown resulting in an emergency auto-rotation landing or accident.

FMI: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/A66ECCB75096D1C2862576B0004B41A4?OpenDocument