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Airworthiness Directive 2006-04-12

recurring
Official AD 2006-04-12 · FR doc 06-1594 · 2006-02-23 · turbine engine

Airworthiness Directives; General Electric Company CF34-1A, -3A, -3A1, -3A2, -3B, and -3B1 Series Turbofan Engines

What this AD requires

The FAA is superseding an existing airworthiness directive (AD) for General Electric Company (GE) CF34-3A1 and -3B1 series turbofan engines. That AD requires initial and repetitive visual inspections and eddy current inspections (ECIs) of certain stage 5 low pressure turbine (LPT) disks and stage 6 LPT disks, installed in GE CF34-3A1 and -3B1 series turbofan engines. Those engines are installed in certain Bombardier Canadair Regional Jet (RJ) airplanes. This AD requires the same initial and repetitive visual inspections and ECIs, but adds SNs to the affected disk population for RJ airplanes. This AD also adds GE CF34-1 and -3 series turbofan engines with certain stage 5 and stage 6 LPT disks, to the applicability section. Those engines are installed in certain Bombardier Canadair Business Jet (BJ) airplanes. Also, this AD requires eventual replacement of the affected disks as terminating action to the repetitive inspections. This AD results from the discovery of an additional population of suspect stage 5 LPT disks and stage 6 LPT disks that could fail due to low-cycle fatigue cracking that may start at the site of an electrical arc-out on the disk. We are issuing this AD to prevent low-cycle-fatigue (LCF) failure of stage 5 LPT disks and stage 6 LPT disks, which could lead to uncontained engine failure.

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 2006-04-12 applies to

MakesGeneral Electric Company (Ge)
ModelsCF34-3A1, CF34-3B1, CF34-1A, CF34-3A, CF34-3A2, CF34-3B, CF34
Part-conditional — 6078T92P01, 6078T89P01, 4922T16P01, 5024T53P01, 5024T53P02, 4922T17P01, 5023T45P03, 5023T45P04.

Two groups: (1) CF34-3A1 and -3B1 engines with stage 5 LPT disk P/N 6078T92P01 or stage 6 LPT disk P/N 6078T89P01, with serial numbers listed in Figure 3 or 4 of GE ASB CF34-AL S/B 72-A0173 Rev 05 (installed on Bombardier CL600-2B19 RJ); (2) CF34-1A, -3A, -3A1, -3A2, and -3B engines with stage 5 LPT disk P/N 4922T16P01, 5024T53P01, or 5024T53P02, or stage 6 LPT disk P/N 4922T17P01, 5023T45P03, or 5023T45P04, with serial numbers listed in Figure 3 or 4 of GE ASB CF34-BJ S/B 72-A0148 Rev 02 (installed on Bombardier CL-600-2A12/2B16/604).

Whether AD 2006-04-12 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 2006-04-12 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.