# Proposed AD 97-NM-93-AD: Lockheed Model 1329-23 and -25 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 98-07-21
- Action: Notice of proposed rulemaking (NPRM).
- Published: January 8, 1998, 63 FR 1076
- Comments due: February 23, 1998
- Became: [AD 98-07-21](https://openairdocs.org/ad/98-07-21)
- Docket: 97-NM-93-AD
- FR document: 98-474
- Official PDF: https://openairdocs.org/files/sha256/bc/9d/bc9d26d964c4130dd3fb65f68d696227bb8439bbf56f45c4f0ebaad814ca1963 (from https://www.govinfo.gov/content/pkg/FR-1998-01-08/pdf/98-474.pdf)
- Federal Register: https://www.federalregister.gov/documents/1998/01/08/98-474/airworthiness-directives-lockheed-model-1329-23-and--25-series-airplanes
- Page: https://openairdocs.org/proposed/97-NM-93-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Lockheed Model 1329-23 and -25 series airplanes. This proposal would require replacement of a certain tailpipe V-band coupling with a new tailpipe V-band coupling. This proposal is prompted by reports indicating that, the flight crew received a fire/overheat warning as a result of displacement of engine tailpipes, which allowed hot exhaust gases into the engine bypass duct. The actions specified by the proposed AD are intended to prevent such displacement, which could result in escape of the hot exhaust gases from the engine tailpipe, and consequent damage to adjacent structure.

## Notices in this docket

- Jan 8, 1998: Notice of proposed rulemaking (NPRM). (first notice), FR document 98-474, comments due Feb 23, 1998 (https://www.federalregister.gov/documents/1998/01/08/98-474/airworthiness-directives-lockheed-model-1329-23-and--25-series-airplanes)

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