# Proposed AD 97-ANE-44-AD: Pratt & Whitney PW4164, PW4168, and PW4168A Series Turbofan Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-16-02
- Products: Pratt & Whitney
- Product type: Engine
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 29, 2005, 70 FR 77075
- Comments due: February 27, 2006
- Became: [AD 2000-16-02](https://openairdocs.org/ad/2000-16-02)
- Docket: 97-ANE-44-AD
- FR document: E5-8020
- Official PDF: https://openairdocs.org/files/sha256/9e/3e/9e3eb606e10c2d86e9e326c6f06158fd45145c3f9f2ae4ea6c306cb0440a2783 (from https://www.govinfo.gov/content/pkg/FR-2005-12-29/pdf/E5-8020.pdf)
- Federal Register: https://www.federalregister.gov/documents/2005/12/29/E5-8020/airworthiness-directives-pratt-and-whitney-pw4164-pw4168-and-pw4168a-series-turbofan-engines
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/AA819CFA34D92E11862570E6005B29BA.0001
- Page: https://openairdocs.org/proposed/97-ANE-44-AD

## Summary

The FAA proposes to supersede an existing airworthiness directive (AD) for Pratt & Whitney (PW) PW4164, PW4168, and PW4168A series turbofan engines. That AD currently requires initial and repetitive torque checks for loose or broken front pylon mount bolts made from INCO 718 material and MP159 material, and initial and repetitive visual inspections of the primary mount thrust load path. This proposed AD would require the same actions, but at reduced intervals for front pylon mount bolts made from MP159 material. This proposed AD results from analysis by the manufacturer that the MP159 material pylon bolts do not meet the full life cycle torque check interval requirement, in a bolt-out condition. We are proposing this AD to prevent front pylon mount bolt and primary mount thrust load path failure, which could result in an engine separating from the airplane.

## Notices in this docket

- Sep 13, 2002: Notice of proposed rulemaking (NPRM). (first notice), FR document 02-23290, comments due Nov 12, 2002 (https://www.federalregister.gov/documents/2002/09/13/02-23290/airworthiness-directives-pratt-and-whitney-pw4164-pw4168-and-pw4168a-series-turbofan-engines)
- Dec 29, 2005: Notice of proposed rulemaking (NPRM)., FR document E5-8020, comments due Feb 27, 2006 (https://www.federalregister.gov/documents/2005/12/29/E5-8020/airworthiness-directives-pratt-and-whitney-pw4164-pw4168-and-pw4168a-series-turbofan-engines)

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