AD/PROP/2 Amdt 4 - Feathering Propellers - Functional Check

This Airworthiness Directive requires operators of piston‑engine aircraft certificated under CASR Part 42 to run a ground functional check of feathering propellers to confirm they fully feather within the aircraft manufacturer’s time limits, every 110 flight hours or 12 months (whichever comes first). The stated purpose is to reduce oil sludge and redistribute grease in the propeller dome. The recurring maintenance time and cost fall on aircraft owners/operators; the AD’s applicability has been narrowed to Part 42 aircraft and will be repealed once incorporated into the Part 42 Manual of Standards.