EASA AD US-2023-08-07
Propellers / Propulsors - Propeller Pitch Control Linkage - Installation
Summary
Federal Aviation Administration Airworthiness Directive 2023-08-07 is a final rule addressing Allied Ag Cat Productions, Inc. Model G-164A and G-164B airplanes equipped with certain supplemental type certificates. This directive mandates the installation of a secondary retention feature on the propeller pitch control (PPC) linkage to prevent detachment from the engine PPC assembly. The affected STCs include SA7769SW, SA7966SW, SA8720SW for Model G-164A and SA7546SW, SA7966SW, SA7987SW, SA8720SW for Model G-164B airplanes.
What Changed
This new airworthiness directive introduces a requirement to install a secondary retention feature consisting of a bolt, washer, and safety wire on the PPC lever and assembly. It also includes instructions for reworking and re-identifying PPC assembly parts if necessary, based on Honeywell Service Bulletin TPE331-72-2190, Revision 0. The AD clarifies the unsafe condition as detachment of the airplane's PPC linkage rather than the engine's PPC linkage.
Why It Matters
This AD is critical for aviation professionals as it addresses a safety risk that previously led to an accident causing serious pilot injury and substantial aircraft damage. Operators and maintenance organizations must ensure compliance to maintain control integrity of the propeller pitch system, thereby preventing potential accidents. Compliance with this directive is essential to uphold airworthiness and regulatory adherence for affected Allied Ag Cat airplanes.
What To Do
Operators of Allied Ag Cat Model G-164A and G-164B airplanes with the specified STCs must install the secondary retention feature within 12 months of June 21, 2023. If PPC assembly rework is required, it must be performed following Honeywell Service Bulletin TPE331-72-2190, Revision 0, including part re-identification. Stakeholders should consult the FAA and Honeywell resources for detailed procedures and ensure documentation of compliance.
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