AD 2021-23-22 Requires Various Inspections Of Certain MR Dampers

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 reports of failed main rotor (MR) dampers. This AD requires various inspections of certain MR dampers, as specified in a European Aviation Safety Agency (now European Union Aviation Safety Agency) (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective January 18, 2022.

Supplementary Information: EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2018-0112R1, dated June 4, 2018 (EASA AD 2018-0112R1), which is the most recent of a series of ADs issued by EASA, to correct an unsafe condition for certain Leonardo S.p.A. Helicopters (formerly Finmeccanica S.p.A., Helicopter Division (FHD), AgustaWestland S.p.A., Agusta S.p.A.), AgustaWestland Philadelphia Corporation (formerly Agusta Aerospace Corporation) Model AB139 and AW139 helicopters.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain serial-numbered Leonardo S.p.A. Model AB139 and AW139 helicopters with an MR damper part number (P/N) 3G6220V01351, 3G6220V01352, or 3G6220V01353 installed. The NPRM published in the Federal Register on March 31, 2020 (85 FR 17788). The NPRM was prompted by reports of failed MR dampers. The NPRM proposed to require, for an affected helicopter with MR damper P/N 3G6220V01351, 3G6220V01352, or 3G6220V01353 installed, reducing the installation torque of each hub attachment bolt for each MR damper. For an affected helicopter with MR damper P/N 3G6220V01351 or 3G6220V01352 installed, the NPRM proposed to require: Repetitively inspecting the MR damper rod end (rod end) and MR damper body end (body end) for a crack; dye penetrant inspecting or eddy current inspecting certain rod and body ends for a crack; repetitively inspecting the rod and body end bearings for rotation in the damper seat and for misaligned slippage marks; repetitively inspecting the rod end broached ring nut; and repetitively inspecting the bearing friction torque value of the body and rod ends, and the MR damper anti-rotation block. Depending on the results of the various inspections, the NPRM proposed to require removing a part from service or replacing a part.

For an affected helicopter with MR damper P/N 3G6220V01351 or 3G6220V01352 installed, the NPRM also proposed to require inspecting each rod end to determine if special washer P/N 3G6220A05052 is installed, and depending on the results, aligning the rod ends and broached rings, replacing any broached ring that cannot be aligned, inspecting the broached rings for wear and damage, and replacing the broached ring and installing a special washer. Lastly, the NPRM proposed to require installing MR damper P/N 3G220V01353, prohibit installing MR damper P/N 3G6220V01351 and P/N 3G6220V01352 on any helicopter, and allow the installation of MR damper P/N 3G220V01353 to constitute terminating action for all of the proposed repetitive required actions.

The FAA issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would apply to Leonardo S.p.a. Model AB139 and AW139 helicopters as identified in EASA AD 2018-0112R1. The SNPRM published in the Federal Register on September 14, 2021 (86 FR 51022). The FAA issued the SNPRM to add an action required by EASA AD 2018-0112R1 that was inadvertently omitted in the NPRM, correct thresholds for different actions proposed in the NPRM, and add the option to accomplish an eddy current inspection for some inspections. The SNPRM also utilized the FAA's new practice of proposing to incorporate EASA AD 2018-0112R1 by reference.

The FAA is issuing this AD to address a crack in an MR damper, which could result in seizure of the MR damper, detachment of the MR damper in-flight, and subsequent loss of control of the helicopter. See EASA AD 2018-0112R1 for additional background information.

FMI: www.regulations.gov