# AD 91-03-18: Warming Ovens - Type: Airworthiness directive - Status: Current - Products: Textron BAe.125 Series 1000A, BAe.125 Series 1000B, BAe.125 Series 800A, BAe.125 Series 800A (C-29A), BAe.125 Series 800A (U-125), BAe.125 Series 800B, BH.125 Series 400A, BH.125 Series 600A, DH.125 Series 1A, DH.125 Series 1A-522, DH.125 Series 1A/R-522, DH.125 Series 1A/S-522 and 30 more - Effective: March 11, 1991 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-6886 - Docket: 90-NM-198-AD - Registered aircraft: 133 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FAC06E54FD0C249186256A09006936E7.0001 - DRS record last changed: January 21, 2026 - Page: https://openairdocs.org/ad/91-03-18 ## The airworthiness directive 91-03-18 BRITISH AEROSPACE: Amendment 39-6886. Docket No. 90-NM-198-AD. Applicability: All Model BAe/DH/HS/BH-125 series airplanes, equipped with Aircraft Products Company (APC) warming ovens having part numbers 255B-LH-28/115, 255B-RH-28/115, or 255-362, certificated in any category. Compliance: Required as indicated, unless previously accomplished. To prevent a warming oven fire and to provide additional overheat protection, accomplish the following: A. Within 60 days after the effective date of this AD, accomplish the following: 1. Inspect the wire insulation inside the warming oven in accordance with British Aerospace Service Bulletin 25-54-9758A&B, Revision 1, dated August 14, 1989. If the oven wiring or thermostat wiring is damaged, prior to further flight, replace the wiring and/or thermostat, as appropriate, in accordance with the service bulletin. 2. Modify the warming ovens by installing an additional thermostat and a new switch, in accordance with British Aerospace Service Bulletin 25-54-9758A&B, Revision 1, dated August 14, 1989. NOTE: British Aerospace Service Bulletin 25-54-9758A&B references Aircraft Products Company (APC) Service Bulletins 255B-25-002, Revision A, dated June 22, 1989, and 255-25-003, dated May 26, 1989, for additional instructions. 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, Transport Airplane Directorate. NOTE: The request should be submitted directly to the Manager, Standardization Branch, ANM-113, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence 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, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041-0414. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. This amendment (39-6886, AD 91-03-18) becomes effective on March 11, 1991. ## 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 40 of 50 models: BAe.125 Series 1000A, HS.125 Series 3B/RB, HS.125 Series 401B, HS.125 Series 600A, HS.125 Series 600B/2, HS.125 Series 403A(C), HS.125 Series 600B/1, HS.125 Series 700A… ## 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: 133 (133 by airframe model, 0 by engine model) - Makers: British Aerospace 89, Corporate Jets 17, Raytheon Corporate Jets 12, Hawker Siddeley 11, Raytheon 3, Hawker Beechcraft 1 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) - [British Aerospace HS 125-700A](https://openairdocs.org/model/british-aerospace-hs-125-700a): 14 aircraft (airframe model) - [British Aerospace BAE 125 SERIES 1000A](https://openairdocs.org/model/british-aerospace-bae-125-series-1000a): 9 aircraft (airframe model) - [Corporate Jets BAE 125-1000A](https://openairdocs.org/model/corporate-jets-bae-125-1000a): 9 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) - [Hawker Siddeley HS.125 SERIES 700A](https://openairdocs.org/model/hawker-siddeley-hs-125-series-700a): 7 aircraft (airframe model) - [British Aerospace BAE 125-800A](https://openairdocs.org/model/british-aerospace-bae-125-800a): 5 aircraft (airframe model) - [Raytheon Corporate Jets BAE 125-1000A](https://openairdocs.org/model/raytheon-corporate-jets-bae-125-1000a): 4 aircraft (airframe model) - [Hawker Siddeley BH.125-400A](https://openairdocs.org/model/hawker-siddeley-bh-125-400a): 2 aircraft (airframe model) - [Hawker Siddeley DH.125-3A/RA](https://openairdocs.org/model/hawker-siddeley-dh-125-3a-ra): 2 aircraft (airframe model) - [Raytheon BAE 125-800A](https://openairdocs.org/model/raytheon-bae-125-800a): 2 aircraft (airframe model) - [Hawker Beechcraft BAE 125-800B](https://openairdocs.org/model/hawker-beechcraft-bae-125-800b): 1 aircraft (airframe model) - [Raytheon HS 125-700A](https://openairdocs.org/model/raytheon-hs-125-700a): 1 aircraft (airframe model) All 16 models: https://openairdocs.org/ad/91-03-18/models.md Every aircraft: https://openairdocs.org/ad/91-03-18/aircraft.md 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.