# Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines
> **Rule** · Final rule. · Published 1999-04-13 · Effective 1999-05-13 · 64 FR 17947
## Document
- **Document number:** 99-8865
- **Category:** airworthiness
- **Manufacturer:** Pratt & Whitney PW4000 Series Turbofan
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 17947
- **Publication date:** 1999-04-13
- **Effective date:** 1999-05-13
- **FAA docket:** Docket No. 98-ANE-66-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), that requires revisions to the Time Limits Section (TLS) of the manufacturer's Engine Manuals (EMs) for Pratt & Whitney (PW) PW4000 series turbofan engines to include required enhanced inspection of selected critical life-limited parts at each piece-part exposure. This amendment will also require an air carrier's approved continuous airworthiness maintenance program to incorporate these inspection procedures. This amendment is prompted by a Federal Aviation Administration (FAA) study of in-service events involving uncontained failures of critical rotating engine parts that indicated the need for improved inspections. The improved inspections are needed to identify those critical rotating parts with conditions that if allowed to continue in service, could result in uncontained failures. The actions specified by this AD are intended to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/04/13/99-8865/airworthiness-directives-pratt-and-whitney-pw4000-series-turbofan-engines)
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