AD 2021-24-01 Prompted By A Report Of Strake Attachment Brackets And The Fuselage Frame Failing

The FAA is adopting a new airworthiness directive (AD) for Pilatus Aircraft Ltd. (Pilatus) Model PC-12/45, PC-12/47, and PC-12/47E airplanes with Supplemental Type Certificate (STC) SA00634DE installed.

This AD was prompted by a report of strake attachment brackets and the fuselage frame failing at the upper most bracket attachment location. This AD requires inspecting the strake, attachment brackets, surrounding structure, and bolts and replacing components and repairing damage if necessary. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective January 13, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to Pilatus Aircraft Ltd. Model PC-12/45, PC-12/47, and PC-12/47E airplanes with STC SA00634DE installed. The NPRM published in the Federal Register on July 22, 2021 (86 FR 38613). The NPRM was prompted by a report of strake attachment brackets and the fuselage frame failing at the upper most bracket attachment location. In the NPRM, the FAA proposed to require inspecting the strake, attachment brackets, and bolts for movement and damage, both internal and external, and replacing components and repairing damage if necessary. The FAA is issuing this AD to prevent buffeting of the strakes. This condition, if not addressed, could result in airplane flutter and reduced lateral stability, which may lead to loss of control of the airplane.

FMI: www.regulations.gov