# AD 91-20-04: Stabilizer Trim Assembly - Type: Airworthiness directive - Status: Current - Products: Boeing 737-300 Series, 737-400 Series and 737-500 Series - Effective: November 7, 1991 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-8038 - Docket: 91-NM-38-AD - Registered aircraft: 42 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/917FA3B8148A218D862569610072DA40.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/91-20-04 ## The airworthiness directive 1-20-04 BOEING: Amendment 39-8038. Docket No. 91-NM-38-AD. Applicability: Boeing Model 737-300, -400, and -500 series airplanes, as listed in Boeing Service Bulletin 737-27-1161, dated November 1, 1990, certificated in any category. Compliance: Required within 36 months after the effective date of this AD, unless previously accomplished. To prevent uncommanded stabilizer movement in the static position, accomplish the following: (a) Remove the existing stabilizer trim jackscrew actuator and replace it with a stabilizer trim assembly that has been modified with the redesigned auxiliary brake assembly in accordance with Boeing Service Bulletin 737-27-1161, dated November 1, 1990. (b) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. NOTE: The request should beforwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO. (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. (d) The replacement requirements shall be done in accordance with Boeing Service Bulletin 737-27-1161, dated November 1, 1990. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C. This amendment (39-8038, AD 91-20-04) becomes effective on November 7, 1991. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A16WE](https://openairdocs.org/tcds/A16WE): The Boeing Company; names 3 of 17 models: 737-500 Series, 737-300 Series, 737-400 Series ## 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: 42 (42 by airframe model, 0 by engine model) - Makers: Boeing 42 Models with the most aircraft: - [Boeing 737-400](https://openairdocs.org/model/boeing-737-400): 8 aircraft (airframe model) - [Boeing 737-500](https://openairdocs.org/model/boeing-737-500): 6 aircraft (airframe model) - [Boeing 737-436](https://openairdocs.org/model/boeing-737-436): 6 aircraft (airframe model) - [Boeing 737-300](https://openairdocs.org/model/boeing-737-300): 4 aircraft (airframe model) - [Boeing 737-490](https://openairdocs.org/model/boeing-737-490): 3 aircraft (airframe model) - [Boeing 737-484](https://openairdocs.org/model/boeing-737-484): 3 aircraft (airframe model) - [Boeing 737-524](https://openairdocs.org/model/boeing-737-524): 3 aircraft (airframe model) - [Boeing 737-505](https://openairdocs.org/model/boeing-737-505): 2 aircraft (airframe model) - [Boeing 737-301](https://openairdocs.org/model/boeing-737-301): 1 aircraft (airframe model) - [Boeing 737-401](https://openairdocs.org/model/boeing-737-401): 1 aircraft (airframe model) - [Boeing 737-306](https://openairdocs.org/model/boeing-737-306): 1 aircraft (airframe model) - [Boeing 737-319](https://openairdocs.org/model/boeing-737-319): 1 aircraft (airframe model) - [Boeing 737-330](https://openairdocs.org/model/boeing-737-330): 1 aircraft (airframe model) - [Boeing 737-405](https://openairdocs.org/model/boeing-737-405): 1 aircraft (airframe model) - [Boeing 737-528](https://openairdocs.org/model/boeing-737-528): 1 aircraft (airframe model) All 15 models: https://openairdocs.org/ad/91-20-04/models.md Every aircraft: https://openairdocs.org/ad/91-20-04/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.