Airworthiness Directives; Textron Lycoming Fuel Injected Reciprocating Engines

This amendment supersedes an existing airworthiness directive (AD), that is applicable to certain Textron Lycoming reciprocating engines with certain Crane/Lear Romec "AN" rotary fuel pumps installed. That AD currently requires initial and follow-up torque check inspections of pump relief valve attaching screws. This amendment requires the same initial and follow-up torque check inspections of relief valve attaching screws, and adds as a terminating action, replacement of the affected fuel pump at or before the overhaul interval, with a fuel pump having a new design valve housing. This amendment is prompted by the introduction of a new design pump relief valve housing and associated parts that provide enhanced resistance to fuel leakage, and the need for clarification of the requirements of the current AD. The actions specified by this AD are intended to prevent rotary fuel pump leaks, which could result in an engine failure, engine fire, and damage to or loss of aircraft.