AD 2022-11-20 Prompted By A Large Crack Detected On The Tail Gearbox (TGB) Fitting During A Scheduled Inspection

The FAA is adopting a new airworthiness directive (AD) for certain Leonardo S.p.a. Model AB139 and AW139 helicopters.

This AD was prompted by a large crack detected on the tail gearbox (TGB) fitting during a scheduled inspection and the determination that certain TGB fittings are required to be inspected by the use of a borescope. This AD requires a one-time borescope inspection of certain part-numbered TGB fittings, and depending on the inspection results, removing the affected part from service and replacing with an airworthy part, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference (IBR). The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 27, 2022. 

Supplementary Information: EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0259, dated November 17, 2021, and corrected November 22, 2021 (EASA AD 2021-0259), to correct an unsafe condition for Leonardo S.p.A. Helicopters, formerly Finmeccanica S.p.A, AgustaWestland S.p.A., Agusta S.p.A.; and AgustaWestland Philadelphia Corporation, formerly Agusta Aerospace Corporation, Model AB139 and AW139 helicopters, all serial numbers. 

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Leonardo S.p.a. Model AB139 and AW139 helicopters. The NPRM published in the Federal Register on March 21, 2022 (87 FR 15899). The NPRM was prompted by a large crack that was detected on the inner forward-right side of TGB fitting part number 3G5351A01151, that was discovered during a scheduled inspection of a Model AW139 helicopter. EASA advises that investigation results determined previous inspections on the inner-right side of the TGB fitting were accomplished without the use of a boroscope. The NPRM proposed to require a one-time borescope inspection of certain part-numbered TGB fittings, and depending on the inspection results, removing the affected part from service and replacing with an airworthy part, as specified in EASA AD 2021-0259.

FMI: www.regulations.gov