# Proposed AD FAA-2011-0944: Pratt & Whitney Division (PW) PW4000 Series Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-04-04
- Products: Pratt & Whitney Division
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 7, 2011, 76 FR 68660
- Comments due: January 6, 2012
- Became: [AD 2012-04-04](https://openairdocs.org/ad/2012-04-04)
- Docket: FAA-2011-0944 (https://www.regulations.gov/docket/FAA-2011-0944, where comments are filed)
- Project: 2011-NE-11-AD
- FR document: 2011-28676
- Official PDF: https://openairdocs.org/files/sha256/89/eb/89eb072ee0679dd89c44121f96336b65a1847db224fa7967705b862d3b50a57b (from https://www.govinfo.gov/content/pkg/FR-2011-11-07/pdf/2011-28676.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/11/07/2011-28676/airworthiness-directives-pratt-and-whitney-division-pw-pw4000-series-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BE97DFD90AFB5B4C86257941004CCE1A.0001
- Page: https://openairdocs.org/proposed/FAA-2011-0944

## Summary

We propose to adopt a new airworthiness directive (AD) for PW4000 series turbofan engines. This proposed AD would require replacing the fuel metering unit (FMU), part number (P/N) 50U150, at the next shop visit after the effective date of this proposed AD. This proposed AD was prompted by an engine overspeed event that occurred during taxi and resulted in a high-pressure compressor (HPC) surge and tailpipe fire. We are proposing this AD to prevent engine overspeed on these engines, which could result in an uncontained engine failure and damage to the airplane.

## Notices in this docket

- Nov 7, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-28676, comments due Jan 6, 2012 (https://www.federalregister.gov/documents/2011/11/07/2011-28676/airworthiness-directives-pratt-and-whitney-division-pw-pw4000-series-turbofan-engines)

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