AD 2001-15-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Pratt | and Whitney PW4000 Series Turbofan | Airworthiness Directives; Pratt and Whitney PW4000 Series Turbofan Engines |
Unsafe Condition
High pressure compressor (HPC) surges in Pratt and Whitney PW4000 series turbofan engines, particularly those with the HPC in the cutback stator (CBS) configuration, leading to multiple-engine power losses and increased single-engine surge events.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Limit the number of engines with the HPC CBS configuration to one on each airplane within 100 cycles-in-service (CIS) after the effective date. Limit the number of PW4000 engines with potentially reduced stability on each airplane, based on configuration, within 50 CIS after the effective date. Remove certain PW4000 engines from service before exceeding cyclic limits on the HPC based on cycles-since-overhaul (CSO), within 50 CIS after the effective date. Prevent the build-up of engines with an HPC having 1,500 or more CSO greater than the high pressure turbine (HPT) CSO. Establish a minimum rebuild standard for engines returned to service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 50 or 100 cycles-in-service (CIS) after the effective date, depending on the specific action.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Pratt and Whitney PW4000 series turbofan engines, specifically those with the HPC in the CBS configuration and those with potentially reduced stability, as defined by the AD. Affected airplane models include Boeing 747, Boeing 767, and McDonnell Douglas MD-11 series airplanes.
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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