AD/PR/13 - Pitch Lock Assembly - Modification - CANCELLED

This document cancels a previous aviation safety rule about aircraft propellers.

Previously, Airworthiness Directive (AD) PR/13 required a specific modification to "pitch lock assemblies" (parts that control propeller blade angle) on Dowty Rotol variable pitch propellers before they could be installed in aircraft after June 1971.

What changes: As of 19 November 2009, aircraft owners, operators, and mechanics no longer need to perform this modification. The Civil Aviation Safety Authority decided this safety requirement was no longer necessary, likely because the affected equipment is obsolete or the risk has been otherwise addressed.