Airworthiness Directive 98-21-24
one-timeAirworthiness Directives; Pratt & Whitney JT8D Series Turbofan Engines
What this AD requires
This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney JT8D series turbofan engines, that requires removal, visual inspection, eddy current inspection, repair or replacement of affected compressor disks. This amendment is prompted by reports of improper fixturing during the electrolytic cleaning process of certain compressor disks at a certified repair station, Avial or Greenwich Air Services, currently GE Engine Services Dallas LP, certificate number RA1R445K of Dallas, Texas, that can result in damage to the disks in the form of arc burns. The actions specified by this AD are intended to prevent compressor disk cracking from arc burns in tie rod holes, shielding holes, or pressure balance holes, which could lead to a fracture of a compressor disk, resulting in uncontained release of engine fragments, inflight engine shutdown, and airframe damage.
Which aircraft AD 98-21-24 applies to
Applies only to specific stage 3 and stage 4 compressor disks identified by part number and serial number in Table 1 of the AD (per GE Engine Services-Dallas, LP, Engineering Bulletin JT8D-025, dated March 27, 1998), regardless of prior modification, alteration, or repair to the affected area.
Whether AD 98-21-24 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:
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.