AD 2022-06-01 Prompted By Reports Of A Main Rotor (M/R) Blade Lead-Lag Damper In A Tilted Position

The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-3 helicopters.

This AD was prompted by reports of a main rotor (M/R) blade lead-lag damper in a tilted position. This AD requires inspecting the Flex Control Unit (FCU), and corrective actions if necessary, as well as rework and re-identification of the bearing pin, as specified in a 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 April 20, 2022.

Supplementary Information: EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0160, dated July 5, 2021 (EASA AD 2021-0160), to correct an unsafe condition for Airbus Helicopters Deutschland GmbH (AHD), formerly Eurocopter Deutschland GmbH, Model MBB-BK117 D-3 helicopters, all serial numbers, including Model MBB-BK117 D-2 helicopters that have been converted into Model MBB-BK117 D-3 helicopters through Airbus Helicopters Service Bulletin MBB-BK117 D-2-00-003. 

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-3 helicopters. The NPRM published in the Federal Register on January 14, 2022 (87 FR 2368). The NPRM was prompted by reports of an M/R blade lead-lag damper in a tilted position. EASA advises that subsequent investigation results determined that the tolerances stack-up may lead to an insufficient clamping on the bearing pin. The NPRM proposed to require inspecting the FCU, and corrective actions if necessary, as well as rework and re-identification of the bearing pin.

The FAA is issuing this AD to address this unsafe condition, which if not detected and corrected, could result in an unbalance of the M/R system, excessive vibration, and reduced control of the helicopter. See EASA AD 2021-0160 for additional background information.

FMI: www.regulations.gov