AD 2021-20-16 Prompted By A Report That, During An Unscheduled Post-Flight Inspection Of The Tail Cone Area, A Crack Was Found...

The FAA is superseding Airworthiness Directive (AD) 2021-04-15, which applied to all Airbus Helicopters Model AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters; and certain Model AS350B3 helicopters.

AD 2021-04-15 required repetitive visual inspections of the right-hand side of the vertical fin spar for discrepancies (cracking), and corrective action if necessary. This AD retains the requirements of AD 2021-04-15, and requires repetitive cleaning and repetitive detailed inspections for cracking of the vertical fin spar and vertical fin upper attachments, and corrective action if necessary, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD also expands the applicability to include additional Model AS350B3 helicopters. This AD was prompted by a report that, during an unscheduled post-flight inspection of the tail cone area, a crack was found in the spar of the upper part of the vertical fin and fractures were found in the two front attachment screws. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective November 22, 2021.

Supplementary Information: The EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0099, dated April 9, 2021 (EASA AD 2021-0099) (also referred to as the Mandatory Continuing Airworthiness Information, or the MCAI), to correct an unsafe condition for all Airbus Helicopters Model AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters; and all Model AS350B3 helicopters except those that have that embodied Airbus Helicopters Modification 073148 in production. EASA stated that recent analysis identified that AS350B3 helicopters modified through Eurocopter AS350 Service Bulletin 55.00.14 (any revision) in service might also be affected by the identified unsafe condition.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2021-04-15, Amendment 39-21437 (86 FR 13165, March 8, 2021) (AD 2021-04-15).

AD 2021-04-15 applied to all Airbus Helicopters Model AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters; and certain Model AS350B3 helicopters. The NPRM published in the Federal Register on June 8, 2021 (86 FR 30395). Since the FAA issued AD 2021-04-15, the FAA has determined that additional actions are required to address the unsafe condition. The NPRM proposed to retain the requirements of AD 2021-04-15, and require repetitive cleaning and repetitive detailed inspections for cracking of the vertical fin spar and vertical fin upper attachments, and corrective action if necessary, as specified in an EASA AD. The NPRM also proposed to expand the applicability to include additional Airbus Helicopters Model AS350B3 helicopters.

The FAA is issuing this AD to address cracking in the spar of the upper part of the vertical fin and fractures in the front attachment screws. This condition could lead to in-flight separation of the upper part of the vertical fin, resulting in loss of control of the helicopter. See the MCAI for additional background information.

FMI: www.regulations.gov