Is AD 98-21-22 a recurring Airworthiness Directive?

Yes — AD 98-21-22 requires a repetitive inspection. Next-due depends on the aircraft's time in service.

Which aircraft does AD 98-21-22 apply to?

AD 98-21-22 applies to Pratt & Whitney — models JT9D-59A, JT9D-70A, JT9D-7Q, JT9D-7Q3, JT9D-7R4, JT9D. Serial/part conditions may narrow it to specific aircraft.

Airworthiness Directive 98-21-22

recurring

Official AD 98-21-22 · FR doc 99-29826 · 1999-11-19 · turbine engine

Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

What this AD requires

This amendment revises an existing airworthiness directive (AD), applicable to Pratt & Whitney JT9D series turbofan engines, that currently requires initial and repetitive eddy current inspections (ECI) of 14th and 15th stage high pressure compressor (HPC) disks for cracks, and removal of cracked disks and replacement with serviceable parts. This amendment revises the definition of a shop visit to make compliance less restrictive, and adds references to a Nondestructive Inspection Procedure attached to applicable service bulletins. This amendment is prompted by feedback from operators saying that the shop visit definition in the current AD made AD compliance unnecessarily restrictive. The actions specified by this AD are intended to prevent 14th and 15th stage HPC disk rupture, which could result in an uncontained engine failure and damage to the airplane.

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 98-21-22 applies to

MakesPratt & Whitney

ModelsJT9D-59A, JT9D-70A, JT9D-7Q, JT9D-7Q3, JT9D-7R4, JT9D

Part-conditional — 5000814-01, 790014, 789914, 790114, 5000815-01, 5000815-021, 704315, 704315-001.

Applies only to engines with 14th and 15th stage high pressure compressor (HPC) disks of these part numbers installed.

Whether AD 98-21-22 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 98-21-22 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.