Airworthiness Directive 99-24-14

one-time
Official AD 99-24-14 · FR doc 99-30624 · 1999-11-26 · turbine engine

Airworthiness Directives; General Electric Company CF6-80E1A2 Series Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6-80E1A2 series turbofan engines. This action requires removing from service stage 2 high pressure turbine (HPT) disks and impeller spacers prior to exceeding new, lower cyclic life limits and imposes a drawdown program for those parts that currently exceed, or will exceed, the new lower limits. This amendment is prompted by the results of a refined low cycle fatigue (LCF) analysis. The actions specified in this AD are intended to prevent LCF cracking and failure of stage 2 HPT disks and impeller spacers, which could result in an uncontained engine failure and damage to the aircraft.

Which aircraft AD 99-24-14 applies to

MakesGeneral Electric
ModelsCF6-80E1A2, CF6
Part-conditional1639M50P03, 1473M85P02.

Applies only to engines with stage 2 high pressure turbine (HPT) disk P/N 1639M50P03 and HPT impeller spacer P/N 1473M85P02 installed.

Whether AD 99-24-14 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 complianceThe specific action taken (inspected, replaced, modified) and to what revision.
DateWhen the work was done.
Aircraft timeTotal time in service / tach at compliance — how recurring next-due is computed.
Signature & certificateThe A&P/IA who returned it to service, with certificate number.
Is AD 99-24-14 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.