AD/TPE 331/7 - Fuel Control - Modification - CANCELLED

What this does: This document officially cancels a 42-year-old aircraft safety rule that required specific fuel control modifications on certain turbine engines.

Who it affects: Owners and operators of aircraft powered by AlliedSignal (formerly Garrett/AiResearch) TPE 331 series turbine engines — commonly used in regional airliners, agricultural aircraft, and military planes.

What changed: The original 1967 rule mandated urgent modifications to fuel controls in accordance with manufacturer service bulletins (SBNo. 25A, B, C or D). As of 24 September 2009, this requirement no longer applies. The Civil Aviation Safety Authority determined the rule was no longer needed for airworthiness.

Why it matters: This removes a longstanding maintenance obligation, potentially saving operators time and money by eliminating a mandatory modification that had been required "forthwith" (immediately) since 1967.