EASA 2020-0099

Mandates a one-time inspection of titanium bolts (Ti-bolts) installed on the forward tail rotor drive shaft to identify whether these are affected parts—defined as having P/N L535M3001201, marked with manufacturer monogram “D”, or those where the manufacturer monogram cannot be identified—that require replacement. AD also prohibits installation of affected parts. Prompted by an investigation of a broken Ti-bolt that found an improper heat treatment process was accomplished on a certain batch of Ti-bolts, which can lead to hydrogen embrittlement of affected parts.