AD 2020-22-17 Requires Replacing And Prohibits Installing Affected Parts

The FAA is adopting a new airworthiness directive (AD) for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product.

The MCAI identifies the unsafe condition as movement of the aft fuel pipe within the coupling, which can cause damage to the O-rings and lead to a fuel leak, fuel fire or explosion, and consequent loss of control of the airplane. This AD requires replacing and prohibits installing affected parts. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective December 14, 2020.

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 Model PC-24 airplanes with a certain part-numbered flexible saddle clamp installed between frame 34 and 36. The NPRM published in the Federal Register on July 30, 2020 (85 FR 45810). The NPRM proposed to require actions to correct the unsafe condition on the specified products and was prompted by MCAI originated by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued AD No. 2019-0240, dated September 25, 2019 (referred to after this as “the MCAI”), which states:

• An occurrence was reported where, during maintenance, when system pressure was applied to a motive-flow fuel pipe, the aft fuel pipe was found to move to the end stop within the coupling. When system pressure was released, the aft fuel pipe returned to its point of origin. This movement can cause damage to the O-rings.
• This condition, if not corrected, could lead to a fuel leak and consequently a fuel contamination of the rear fuselage, which, in combination with an ignition source in this area, could possibly result in a fuel fire or fuel vapour explosion and consequent loss of the aeroplane.
• To address this potential unsafe condition, Pilatus issued the [service bulletin] SB to provide modification instructions.
• For the reason described above, this [EASA] AD requires replacement of affected parts with serviceable parts, as defined in this AD, and prohibits (re-) installation of affected parts.

You may examine the MCAI on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0719.

FMI: www.regulations.gov