AD Amdt-39-10873
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney | PW4000 Series | Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines |
Unsafe Condition
Reports of high pressure compressor (HPC) surge caused by excessive HPC rear stage rotor-to-case clearance.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Grind HPC blade tips at the rotor assembly, install aluminum oxide coated HPC blade tips in stages 9 through 12, modify HPC 8th through 14th stage stators, incorporate 1st stage high pressure turbine (HPT) vanes with increased airflow area along with additional HPT hardware modifications, and incorporate HPC 13th-15th stage zirconium oxide blade tips.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 1,400 cycles in service (CIS) after the effective date of this AD, or prior to June 30, 1999, whichever occurs first.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt & Whitney Model PW4152, PW4056, PW4156, PW4256, PW4052, PW4158, PW4060, PW4160, PW4460, PW4050, PW4060A, PW4156A, PW4062, PW4462, PW4060C, and PW4650 turbofan engines, not incorporating at least one of the modifications described in the listed PW service bulletins.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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