Is AD 99-24-15 a recurring Airworthiness Directive?

Yes — AD 99-24-15 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 99-24-15 apply to?

AD 99-24-15 applies to General Electric — models CF6-45, CF6-50, CF6-80A, CF6-80C2, CF6-80E1, CF6. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 99-24-15

recurring

Official AD 99-24-15 · FR doc 99-30724 · 1999-11-29 · turbine engine

Airworthiness Directives; General Electric Company CF6 Series Turbofan Engines

What this AD requires

This amendment supersedes an existing airworthiness directive (AD), applicable to General Electric Company (GE) CF6 series turbofan engines, that currently requires initial and repetitive ultrasonic and eddy current inspections of high pressure compressor rotor (HPCR) stage 3-9 spools for cracks. This amendment defines more aggressive inspection intervals for certain HPCR stage 3-9 spools, adds CF6-80E1 engines to the inspection program, adds inspection requirements for spools manufactured from 8 inch diameter billet, adds inspection requirements for stage 3-5 blade slot bottoms, and adds inspection requirements for web and hub-to-web transition areas. This amendment is prompted by analysis of recent HPCR stage 3-9 spool inspection results and separations, and assessment of the adequacy of the existing program to prevent HPCR stage 3-9 spool cracking and separation. As a result of that assessment, the FAA has determined there is a need to make changes to the existing AD. The actions specified by this AD are intended to prevent HPCR stage 3-9 spool cracking and separation, which can result in an uncontained engine failure and aircraft damage.

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 99-24-15 applies to

MakesGeneral Electric

ModelsCF6-45, CF6-50, CF6-80A, CF6-80C2, CF6-80E1, CF6

Part-conditional — 1333M66G01, 1333M66G03, 1333M66G07, 1333M66G09, 1333M66G10, 1669M22G01, 1669M22G03, 1781M52P01.

Applies only to engines with a High Pressure Compressor Rotor (HPCR) stage 3-9 spool of these part numbers installed.

Whether AD 99-24-15 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 99-24-15 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.