# AD 91-03-15: Tailpipe Coupling

- Type: Airworthiness directive
- Status: Historical
- Products: Mooney M20M
- Effective: February 19, 1991
- Superseded by: [AD 2004-23-17](https://openairdocs.org/ad/2004-23-17)
- Product type: Aircraft, Small airplane
- Amendment: 39-6870
- Docket: 90-CE-74-AD
- Registered aircraft: 249 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/907A7C3DA9D8206486256A64004EC2E9.0001
- DRS record last changed: August 7, 2025
- Page: https://openairdocs.org/ad/91-03-15

## The airworthiness directive

91-03-15 MOONEY AIRCRAFT CORPORATION: Amendment 39-6870; Docket No. 90-CE-74-AD.

Applicability: Model M20M airplanes (serial numbers (S/N 27-0001 through 27-0071, S/N 27-0073, S/N 27-0075, and S/N 27-0076), certificated in any category.

Compliance: Required within the next 25 hours time-in-service after the effective date of this AD, unless already accomplished.

To prevent the discharge of high temperature exhaust gases inside the engine compartment that could result in the airplane cabin catching fire, accomplish the following:

  (a) Replace the tailpipe coupling (P/N MVT69183-275, LW-12093-8, 4571-275, 4574-275, or 4391 AF) with an improved tailpipe coupling (P/N 55677-340M or 40D21162-340M) in accordance with the instructions in Mooney Aircraft Corporation Special Letter 90-06, dated November 1, 1990.

  (b) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

  (c) An alternate method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, FAA, Southwest Region, Airplane Certification Office, Fort Worth, Texas 76193-0150. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Fort Worth Airplane Certification Office.

  (d) All persons affected by this directive may obtain copies of the document referred to herein upon request to Mooney Aircraft Corporation, P.O. Box 72, Kerrville, Texas 78029-0072; Telephone (512) 896-6000; or may examine this document at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

This amendment (39-6870, AD 91-03-15) becomes effective on February 19, 1991.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 2A3](https://openairdocs.org/tcds/2A3): Mooney International Corporation; names 1 of 17 models: M20M

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 249 (249 by airframe model, 0 by engine model)
- Makers: Mooney 249

Models with the most aircraft:

- [Mooney M20M](https://openairdocs.org/model/mooney-m20m): 249 aircraft (airframe model)

All 1 models: https://openairdocs.org/ad/91-03-15/models.md
Every aircraft: https://openairdocs.org/ad/91-03-15/aircraft.md

## Related documents

- [AD 2004-23-17](https://openairdocs.org/ad/2004-23-17): Tailpipe coupling · Mooney M20M. Effective Dec 1, 2004. Supersedes this AD

Its text cites no advisory circulars or STCs.

---
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.