# AD 86-18-04: Self-Locking Nuts - Type: Airworthiness directive - Status: Current - Products: Boeing 737-100 Series, 737-200 Series, 737-200C Series, 737-300 Series, 737-400 Series, 737-500 Series, 737-600 Series, 737-700 Series and 737-800 Series - Effective: September 11, 1986 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-5385 - Registered aircraft: 823 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FD69F21CAE65C4A8862568AA0069C126.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/86-18-04 ## The airworthiness directive 86-18-04 BOEING: Amendment 39-5385. Applies to Model 737 series airplanes, line numbers 930 and above, listed in Boeing Service Letter 737-SL-27-38, dated January 16, 1986, certificated in any category. To detect nuts installed at the Body Buttock Line (BBL) 70.85 wing-to-body splice plate, the thrust reverser secondary deactivation pin, and the vertical fin front spar to closure rib attachments, that have insufficient self-locking torque characteristics, accomplish the following, unless already accomplished: A. Within the next 18 months after the effective date of this AD, check the self- locking nuts, P/N BACN10JC12CM and P/N BACN10JC12CD, for proper self-locking torque in accordance with Paragraph II of Boeing Service Letter 737-SL-27-38, dated January 16, 1986, or later FAA-approved revision. If any self-locking nut does not meet the torque criteria specified in the service letter, replace it prior to further flight with an appropriate nut which meets the torque criteria. B. An alternate means of the 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, FAA, Northwest Mountain Region. C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD. All persons affected by this directive who have not already received the appropriate service document from the manufacturer may obtain copies upon request to the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. This document may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington. This amendment becomes effective September 11, 1986. ## 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 9 of 17 models: 737-500 Series, 737-100 Series, 737-200C Series, 737-800 Series, 737-300 Series, 737-200 Series, 737-700 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: 823 (823 by airframe model, 0 by engine model) - Makers: Boeing 823 Models with the most aircraft: - [Boeing 737-823](https://openairdocs.org/model/boeing-737-823): 278 aircraft (airframe model) - [Boeing 737-800](https://openairdocs.org/model/boeing-737-800): 139 aircraft (airframe model) - [Boeing 737-824](https://openairdocs.org/model/boeing-737-824): 135 aircraft (airframe model) - [Boeing 737-832](https://openairdocs.org/model/boeing-737-832): 73 aircraft (airframe model) - [Boeing 737-890](https://openairdocs.org/model/boeing-737-890): 60 aircraft (airframe model) - [Boeing 737-724](https://openairdocs.org/model/boeing-737-724): 36 aircraft (airframe model) - [Boeing 737-790](https://openairdocs.org/model/boeing-737-790): 14 aircraft (airframe model) - [Boeing 737-752](https://openairdocs.org/model/boeing-737-752): 13 aircraft (airframe model) - [Boeing 737-400](https://openairdocs.org/model/boeing-737-400): 8 aircraft (airframe model) - [Boeing 737-852](https://openairdocs.org/model/boeing-737-852): 7 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 737-700](https://openairdocs.org/model/boeing-737-700): 5 aircraft (airframe model) - [Boeing 737-300](https://openairdocs.org/model/boeing-737-300): 4 aircraft (airframe model) - [Boeing 737-883](https://openairdocs.org/model/boeing-737-883): 4 aircraft (airframe model) - [Boeing 737-205](https://openairdocs.org/model/boeing-737-205): 3 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 737-732](https://openairdocs.org/model/boeing-737-732): 3 aircraft (airframe model) - [Boeing 737-524](https://openairdocs.org/model/boeing-737-524): 3 aircraft (airframe model) All 40 models: https://openairdocs.org/ad/86-18-04/models.md Every aircraft: https://openairdocs.org/ad/86-18-04/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.