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 the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
PW206 and PW207 compressor turbine (CT) disc bore areas may experience impact damage resulting from bending or fracture of the CT disc retaining nut. Damage of the CT disc bore area can reduce LCF capabilities of the CT disc, resulting in disc fracture.
We are proposing this AD to prevent damage to the CT disc bore area, which could result in possible uncontained failure of the engine and damage to the helicopter.