AD 2021-05-21 Requires Replacing Each Affected Bearing With A Certain Part-Numbered Bearing

The FAA is superseding Airworthiness Directive (AD) 2017-23-08 for Agusta S.p.A. (now Leonardo S.p.a.) Model AB139 and AW139 helicopters.

 AD 2017-23-08 required repetitively inspecting the main rotor (M/R) rotating scissors, removing certain lower half scissor spherical bearings (bearings) from service, replacing the removed bearings with a new bearing, and installing a special nut. This new AD retains the requirements of AD 2017-23-08 and requires replacing each affected bearing with a certain part-numbered bearing. This AD was prompted by investigation results determining that a quality control issue may have affected the production of the affected bearings. The actions of this AD are intended to address an unsafe condition on these products. This AD is effective May 7, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2017-23-08, Amendment 39-19102 (82 FR 55752, November 24, 2017) (AD-2017-23-08). AD 2017-23-08 applied to Agusta S.p.A. (now Leonardo S.p.a.) Model AB139 and AW139 helicopters with M/R rotating scissors with a bearing part number (P/N) 3G6230V00654 installed.

The NPRM published in the Federal Register on September 15, 2020 (85 FR 57165). The NPRM proposed to retain the repetitive inspection requirements of AD 2017-23-08, and continue to require replacing the bearing with an improved bearing, replacing the rotating scissor attachment flange with a certain part-numbered rotating scissor attachment flange, and replacing the nut with a certain partnumbered special nut. The NPRM also proposed to require removing each bearing P/N 3G6230V00654 from service and replacing it with bearing P/N 3G6230V00655 within 100 hours time-in-service (TIS).

The NPRM was prompted by EASA Emergency AD (EAD) No. 2017-0028-E, dated February 15, 2017 (EASA EAD 2017-0028-E) issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for Leonardo S.p.a. Model AB139 and AW139 helicopters. EASA advises that investigation results by the supplier of the bearings determined that a quality control issue may have affected the production of bearing P/N 3G6230V00654. Accordingly, this AD retains the requirements of AD 2017-23-08 and requires replacing bearing P/N 3G6230V00654 with P/N 3G6230V00655.

FMI: www.regulations.gov