AD 2022-07-12 Prompted By A Report Of A Crack In A Rotating Scissor Fitting

The FAA is superseding Airworthiness Directive (AD) 2021-02-20, which applied to certain Hélicoptères Guimbal (HG) Model Cabri G2 helicopters.

AD 2021-02-20 required initial and repetitive inspections of certain rotating and non-rotating scissor fittings, and depending on the results, replacing the affected assembly. AD 2021-02-20 also prohibited installing certain main rotor hubs (MRHs) and swashplate guides unless the initial inspection was accomplished. This AD was prompted by a report of a crack in a rotating scissor fitting. This AD retains certain requirements of AD 2021-02-20, and requires installation of newly designed parts, provides a terminating action for the initial and repetitive inspections, and revises the applicability. This AD also extends the repetitive inspection interval and prohibits installing certain MRHs and swashplate guides. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective May 10, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2021-02-20, Amendment 39-21403 (86 FR 8299, February 5, 2021) (AD 2021-02-20). AD 2021-02-20 applied to HG Model Cabri G2 helicopters, with rotating or non-rotating scissor fitting part number (P/N) G12-00-200, installed on the MRH or swashplate guide, respectively. The NPRM published in the Federal Register on January 31, 2022 (87 FR 4822). In the NPRM, the FAA proposed to retain certain inspection and corrective action requirements of AD 2021-02-20. The NPRM also proposed to require within 60 hours time-in-service (TIS) or 6 months, whichever occurs first after the effective date of the proposed AD, and thereafter at intervals not to exceed 60 hours TIS or 6 months, whichever occurs first, leaving each scissor fitting assembled and visually inspecting each scissor fitting for a crack. If there is a crack during the initial inspection or the recurring inspection, the NPRM proposed to require before further flight, replacing certain parts or as an alternative, installing HG modification (mod) 20-040.

The NPRM proposed to require, within 60 months or during the next main gearbox overhaul, whichever occurs first after the effective date of the proposed AD, removing from service MRH P/N G12-00-100, or G12-00-101, or G12-00-102 and swashplate guide P/N G21-01-101 or G21-01-102 and installing HG mod 20-040. The proposed NPRM also allowed installing HG mod 20-040 to be a terminating action for the initial and recurring visual inspections required by the proposed AD.

Additionally, for any pre-HG mod 20-040 helicopter, as of February 22, 2021 (the effective date of AD 2021-02-20), the NPRM proposed to prohibit installing an MRH or swashplate guide, with a certain part-numbered rotating or non-rotating scissor fitting installed, unless certain actions have been accomplished. For any post-HG mod 20-040 helicopter, as of the effective date of the proposed AD, the NPRM proposed to prohibit installing an MRH or swashplate guide, with a certain part-numbered rotating or non-rotating scissor fitting installed, on any helicopter.

The NPRM was prompted by EASA AD 2021-0155, dated July 2, 2021 (EASA AD 2021-0155), issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for HG Cabri G2 helicopters, all manufacturer serial numbers. EASA advises that a design change was developed for the MRH and swashplate guide including installation instructions for the modification. EASA AD 2021-0155 advises the design change requires installing new scissor fitting P/N G12-00-202, which is not affected by stress corrosion cracking. EASA AD 2021-0155 further advises once a helicopter installs a certain part-numbered MRH and a certain part-numbered swashplate guide containing the newly designed scissor fitting, HG mod 20-040 is accomplished. This condition, if not addressed, could result in failure of a rotating or non-rotating scissor fitting and subsequent loss of control of the helicopter.

Accordingly, EASA AD 2021-0155 retains the requirements of EASA AD 2020-0199, dated September 21, 2020, and corrected September 24, 2020 (EASA AD 2020-0199), which prompted AD 2021-02-20, and requires replacement of the MRH and swashplate guide assemblies with assemblies equipped with the newly designed scissor fitting. EASA AD 2021-0155 also increases the interval for the repetitive inspection and prohibits any affected part to be installed on any helicopter that has HG mod 20-040 installed. EASA AD 2021-0155 allows a terminating action for the initial and repetitive inspections if the helicopter has been modified and includes the updated modification information.

FMI: www.regulations.gov