AD/PA-31/81 - Heater Fuel Drain Hose - Modification - CANCELLED

This document cancels a previous aircraft safety rule for Piper PA-31 series aeroplanes (twin-engine aircraft like the Navajo and Chieftain).

What the old rule required: The original directive (from 1979) required owners to modify the heater fuel drain hose — a component that drains excess fuel from the cabin heating system. Aircraft had to be modified according to Piper Service Bulletin No. 641 within 100 hours of flight time after July 1979.

What this document does: It officially cancels that requirement effective 31 July 2008. The rule is no longer needed because all affected aircraft have already been modified.

Who is affected: Owners and operators of Piper PA-31 series aircraft. However, since the work has been completed across the fleet, this simply removes an obsolete requirement from the books.