AD 99-20-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | JT9D-7R4D | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
| engine | Pratt & Whitney Division | JT9D-7R4D1 | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
| engine | Pratt & Whitney Division | JT9D-7R4E | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
| engine | Pratt & Whitney Division | JT9D-7R4E1 | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
| engine | Pratt & Whitney Division | JT9D-7R4E4 | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
| engine | Pratt & Whitney Division | JT9D-7R4G2 | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
| engine | Pratt & Whitney Division | JT9D-7R4H1 | Airworthiness Directives; Pratt & Whitney JT9D-7R4 Series Turbofan Engines |
Unsafe Condition
High Pressure Turbine (HPT) stage 1 and stage 2 disks may have subsurface anomalies formed during the forging process, which could result in an HPC disk fracture, uncontained engine failure, damage to the airplane, and in-flight engine shutdown.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Perform initial and repetitive ultrasonic inspections of HPT stage 1 and 2 disks at approved facilities during shop visits. Remove and replace disks with serviceable parts if subsurface anomalies are detected via cracks. Compliance requires adherence to Pratt & Whitney Service Bulletin JT9D-7R4-72-553, Revision 1.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the effective date of the AD (October 29, 1999), when disks are exposed during shop visits.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney JT9D-7R4 series turbofan engines installed on Boeing 747, Airbus A300, and Airbus A310 series airplanes, specifically engines with HPT stage 1 or 2 disks having serial numbers listed in PW SB JT9D-7R4-72-553, Revision 1.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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