AD 2020-22-04 Requires An Inspection To Determine If Ti-Bolts Installed On The Forward And Aft Tail Rotor Drive Shafts Are Affected Parts

The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters.

This AD was prompted by reports of improper heat treatment of titanium (Ti)-bolts installed on the forward and aft tail rotor drive shafts, resulting in a broken Ti-bolt. This AD requires an inspection to determine if Ti-bolts installed on the forward and aft tail rotor drive shafts are affected parts, and replacement if necessary, 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 becomes effective November 18, 2020.

Supplementary Information: The EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2020-0099, dated May 5, 2020 (EASA AD 2020-0099) (also referred to as the Mandatory Continuing Airworthiness Information, or “the MCAI”), to correct an unsafe condition for all Airbus Helicopters Deutschland GmbH Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, EC635P2+, EC635P3, EC635T1, EC635T2+, and EC635T3 helicopters.

Model EC635P3, EC635P2+, EC635T1, and EC635T3 helicopters are not certificated by the FAA and are not included on the U.S. type certificate data sheet; this AD therefore does not include those helicopters in the applicability.

This AD was prompted by reports of improper heat treatment of Ti-bolts on the forward and aft tail rotor drive shafts, resulting in a broken Ti-bolt.

The FAA is issuing this AD to address improper heat treatment of Ti-bolts on the forward and aft tail rotor drive shafts, which could result in rupture of a Ti-bolt installed in a critical location, possibly resulting in reduced control of the helicopter.

See the MCAI for additional background information.

FMI: www.regulations.gov