AD 2021-07-12 Was Prompted By A Reassessment Of The Flight Control System

The FAA is adopting a new airworthiness directive (AD) for Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters.

This AD was prompted by a reassessment of the flight control system. This AD requires modification of the cyclic stick, 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 May 11, 2021.

Supplementary Information: EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2018-0063, dated March 22, 2018 (EASA AD 2018-0063) (also referred to as the Mandatory Continuing Airworthiness Information, or the MCAI), to correct an unsafe condition for Airbus Helicopters Deutschland GmbH (AHD) formerly Eurocopter Deutschland GmbH (ECD), Eurocopter España S.A, Model EC135 P1, EC135 P2, EC135 P2+, EC135 P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+, EC635 P3, EC635 T1, EC635 T2+ and EC635 T3 helicopters, all variants, all serial numbers (S/Ns) up to 1263 inclusive and S/N 1265, if equipped with autopilot, and S/N 2001 up to 2024 inclusive, except S/N 2006, 2008, 2013, 2017, 2019, 2020 and 2022.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, and EC135T3 helicopters. The NPRM published in the Federal Register on January 19, 2021 (86 FR 5040). The NPRM was prompted by a reassessment of the flight control system, which revealed that uncommanded disengagement of the main rotor trim actuators during flight with the autopilot engaged and hands-off controls could result in high roll and pitch rates, which would require pilot intervention within a reaction time below that required by current airworthiness standards. The NPRM proposed to require installing a cyclic stick weight compensation modification to correct this unsafe condition, which if not corrected may lead to subsequent loss of control of the helicopter, as specified in an EASA AD.

FMI: www.regulations.gov