# Proposed AD 97-NM-311-AD: Boeing Model 757-200 Series Airplanes Powered by Rolls-Royce RB211-535E4/E4B Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 98-25-12
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 26, 1998, 63 FR 14652
- Comments due: May 11, 1998
- Became: [AD 98-25-12](https://openairdocs.org/ad/98-25-12)
- Docket: 97-NM-311-AD
- FR document: 98-7880
- Official PDF: https://openairdocs.org/files/sha256/2a/8d/2a8dd9c7f3dcff1e5a539e4b66f44105c1541ceb41589e94a3e3d48773852127 (from https://www.govinfo.gov/content/pkg/FR-1998-03-26/pdf/98-7880.pdf)
- Federal Register: https://www.federalregister.gov/documents/1998/03/26/98-7880/airworthiness-directives-boeing-model-757-200-series-airplanes-powered-by-rolls-royce-rb211-535e4e4b
- Page: https://openairdocs.org/proposed/97-NM-311-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 757-200 series airplanes. This proposal would require repetitive inspections to detect cracking of the acoustic panels in the engine inlet, and repair, if necessary. This proposal also would require eventual replacement of the existing engine inlet with a new inlet, which, when accomplished, would terminate the repetitive inspections. This proposal is prompted by reports of cracking of acoustic panels in the engine inlet, and incidents of pieces of the panels breaking off and being ingested into the engine. The actions specified by the proposed AD are intended to detect and correct cracking of the acoustic panels in the engine inlet, which could result in reduced structural integrity of the engine inlet, and consequent engine shutdown or surge; or in the event of a fan blade failure, separation of the inlet from the engine.

## Notices in this docket

- Mar 26, 1998: Notice of proposed rulemaking (NPRM). (first notice), FR document 98-7880, comments due May 11, 1998 (https://www.federalregister.gov/documents/1998/03/26/98-7880/airworthiness-directives-boeing-model-757-200-series-airplanes-powered-by-rolls-royce-rb211-535e4e4b)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.