# Airworthiness Directives; Lockheed Model 1329-23 and -25 Series Airplanes
> **Rule** · Final rule. · Published 1998-04-13 · Effective 1998-05-18 · 63 FR 17931
## Document
- **Document number:** 98-9587
- **Category:** airworthiness
- **Manufacturer:** Lockheed Model 1329-23 and -25 Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 63 FR 17931
- **Publication date:** 1998-04-13
- **Effective date:** 1998-05-18
- **FAA docket:** Docket No. 97-NM-93-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain Lockheed Model 1329-23 and -25 series airplanes, that requires replacement of a certain tailpipe V-band coupling with a new tailpipe V-band coupling. This amendment 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 this 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.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1998/04/13/98-9587/airworthiness-directives-lockheed-model-1329-23-and--25-series-airplanes)
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