# Airworthiness Directives; Pratt & Whitney (PW)Turbofan Engines
> **Rule** · Final rule. · Published 2012-03-23 · Effective 2012-04-27 · 77 FR 16916
## Document
- **Document number:** 2012-6952
- **Category:** airworthiness
- **Manufacturer:** Pratt & Whitney (PW)Turbofan
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 77 FR 16916
- **Publication date:** 2012-03-23
- **Effective date:** 2012-04-27
- **FAA docket:** Docket No. FAA-2011-1176
## Abstract

We are adopting a new airworthiness directive (AD) for PW JT9D-7R4G2 and -7R4H1 turbofan engines. This AD was prompted by the determination that a new lower life limit for high-pressure turbine (HPT) 1st stage air seals, part number (P/N) 735907, is necessary. This AD establishes a new lower life limit for HPT 1st stage air seals, P/N 735907, and requires removing them from service using a drawdown schedule. We are issuing this AD to prevent critical life-limited rotating engine part failure and damage to the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2012/03/23/2012-6952/airworthiness-directives-pratt-and-whitney-pwturbofan-engines)
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