# Airworthiness Directives; Pratt & Whitney PW4090 and PW4090-3 Turbofan Engines
> **Rule** · Final rule. · Published 2009-02-17 · Effective 2009-03-24 · 74 FR 7304
## Document
- **Document number:** E9-3041
- **Category:** airworthiness
- **Manufacturer:** Pratt & Whitney PW4090 and PW4090-3 Turbofan
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 74 FR 7304
- **Publication date:** 2009-02-17
- **Effective date:** 2009-03-24
- **FAA docket:** Docket No. FAA-2007-29110
## Abstract

The FAA is adopting a new airworthiness directive (AD) for Pratt & Whitney (PW) PW4090 and PW4090-3 turbofan engines with front turbine hub, part number (P/N) 53L601, installed. This AD reduces the published life limit of those front turbine hubs, from 12,000 cycles- since-new (CSN) to 9,370 CSN. This AD also removes from service those front turbine hubs using a drawdown schedule. This AD results from PW updating the low-cycle-fatigue (LCF) life analysis for front turbine hubs, P/N 53L601. We are issuing this AD to prevent an uncontained failure of the front turbine hub, resulting in an in-flight engine shutdown and possible damage to the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2009/02/17/E9-3041/airworthiness-directives-pratt-and-whitney-pw4090-and-pw4090-3-turbofan-engines)
---
*AI Analytics · CC0 1.0*