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Airworthiness Directive 97-05-11

recurring
Official AD 97-05-11 · FR doc 97-20192 · 1997-08-01 · turbine engine

Airworthiness Directives; AlliedSignal Inc. ALF502 and LF507 Series Turbofan Engines

What this AD requires

This amendment revises an existing airworthiness directive (AD), applicable to AlliedSignal Inc. ALF502 and LF507 series turbofan engines, that currently requires initial and repetitive inspections of the oil system chip detectors and oil filter bypass valve, and optional installation of an improved oil filter bypass valve, to ensure the integrity of the reduction gear system and overspeed protection system. This amendment adds an initial inspection threshold for the oil maintenance requirements that was inadvertently omitted from AD 97-05- 11, and makes editorial corrections. Paragraphs (b) through (f) of AD 97-05-11 have been rearranged in this AD to make these corrections. This amendment is prompted by the inadvertent omission of the initial inspection threshold. The actions specified by this AD are intended to prevent No. 4 and 5 duplex bearing failure, which can result in a Stage 4 low pressure turbine (LPT) rotor failure, an uncontained engine failure, and damage to the aircraft.

Repetitive inspection. Re-inspect. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 97-05-11 applies to

MakesAlliedsignalTextron Lycoming
ModelsALF502, LF507

Whether AD 97-05-11 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.

How AD compliance is recorded

A valid compliance record (14 CFR 43.9) states:

Method of compliance — The specific action taken (inspected, replaced, modified) and to what revision.
Date — When the work was done.
Aircraft time — Total time in service / tach at compliance — how recurring next-due is computed.
Signature & certificate — The A&P/IA who returned it to service, with certificate number.
Is AD 97-05-11 complied with on your aircraft?

Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.

Look up a tail number →Read the full directive (Federal Register)

Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.