# AD 89-21-06: Engine Exhaust Duct

- Type: Airworthiness directive
- Status: Current
- Products: Textron BAe.125 Series 800A, BAe.125 Series 800A (C-29A) and BAe.125 Series 800A (U-125)
- Effective: November 8, 1989
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-6346
- Docket: 89-NM-87-AD
- Registered aircraft: 84 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D9BDDDA672E854E5862569F30055BD5E.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/89-21-06

## The airworthiness directive

89-21-06 BRITISH AEROSPACE: Amendment 39-6346. Docket No. 89-NM-87-AD.

Applicability: Model BAe 125-800A series airplanes equipped with Grumman Aerospace Corporation engine exhaust duct Part No. C46P13100-3 or C46P13100-103 (not applicable to airplanes with Dee Howard thrust reversers) certificated in any category.

Compliance: Required within 180 days after the effective date of this AD, unless previously accomplished.

To prevent collapse of the engine exhaust duct, accomplish the following:

A. Replace the left and right engine exhaust ducts in accordance with British Aerospace Service Bulletin 71-40-3213A, Revision 2, dated April 12, 1989.

B. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Northwest Mountain Region.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, Standardization Branch, ANM-113.

C. 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.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to British Aerospace, PLC, Service Bulletin Librarian, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

This amendment (39-6346, AD 89-21-06) becomes effective on November 8, 1989.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A3EU](https://openairdocs.org/tcds/A3EU): Textron Aviation Inc.; names 1 of 50 models: BAe.125 Series 800A (U-125)

## 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: 84 (84 by airframe model, 0 by engine model)
- Makers: British Aerospace 66, Corporate Jets 8, Raytheon Corporate Jets 8, Raytheon 2

Models with the most aircraft:

- [British Aerospace BAE 125 SERIES 800A](https://openairdocs.org/model/british-aerospace-bae-125-series-800a): 61 aircraft (airframe model)
- [Corporate Jets BAE 125-800A](https://openairdocs.org/model/corporate-jets-bae-125-800a): 8 aircraft (airframe model)
- [Raytheon Corporate Jets BAE 125-800A](https://openairdocs.org/model/raytheon-corporate-jets-bae-125-800a): 8 aircraft (airframe model)
- [British Aerospace BAE 125-800A](https://openairdocs.org/model/british-aerospace-bae-125-800a): 5 aircraft (airframe model)
- [Raytheon BAE 125-800A](https://openairdocs.org/model/raytheon-bae-125-800a): 2 aircraft (airframe model)

All 6 models: https://openairdocs.org/ad/89-21-06/models.md
Every aircraft: https://openairdocs.org/ad/89-21-06/aircraft.md

Its text cites no advisory circulars or STCs.

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