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Airworthiness Directive 99-21-18

recurring
Official AD 99-21-18 · FR doc 99-26568 · 1999-10-18 · airframe

Airworthiness Directives; Boeing Model 767 Series Airplanes Powered by Pratt & Whitney JT9D-7R4 Series Turbofan Engines or General Electric CF6-80A Series Turbofan Engines

What this AD requires

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires repetitive inspections to detect certain discrepancies of the cables, fittings, and pulleys of the engine thrust control cables; and repair, if necessary. For certain airplanes, this amendment also requires replacement of certain pulleys with new pulleys, and re-rigging of the engine thrust control cable. This amendment is prompted by reports of engine thrust control cable failures. The actions specified by this AD are intended to prevent such failures, which could result in a severe asymmetric thrust condition during landing, and consequent reduced controllability of the airplane.

Repetitive inspection. Re-inspect every 18 months. The next-due date/hours depend on this aircraft’s time in service — a records report computes it from the logbooks.

Which aircraft AD 99-21-18 applies to

MakesBoeing
Models767

All 767 airplanes require thrust control cable inspection; airplanes identified in Boeing Service Bulletin 767-76-0010, Revision 1, dated February 20, 1992, additionally require replacement of two non-metallic thrust control cable pulleys with aluminum pulleys and re-rigging.

Whether AD 99-21-18 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 99-21-18 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.