AD 86-18-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 737-100 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-200 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-200C Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-300 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-400 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-500 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-600 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-700 Series | BOEING Model 737 Series Airplanes |
| aircraft | The Boeing Company | 737-800 Series | BOEING Model 737 Series Airplanes |
Unsafe Condition
Self-locking nuts (P/N BACN10JC12CM and P/N BACN10JC12CD) installed at the Body Buttock Line (BBL) 70.85 wing-to-body splice plate, thrust reverser secondary deactivation pin, and vertical fin front spar to closure rib attachments have insufficient self-locking torque characteristics.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Within 18 months after the effective date, check the self-locking nuts for proper self-locking torque per Boeing Service Letter 737-SL-27-38. Replace any nut not meeting torque criteria prior to further flight. Alternate compliance may be approved by the FAA Manager, Seattle Aircraft Certification Office.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 18 months after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 737 series airplanes, line numbers 930 and above, listed in Boeing Service Letter 737-SL-27-38 dated January 16, 1986.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Self-Locking Nuts
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_86-18-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 86-18-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: BOEING Model 737 Series Airplanes Subject: Self-Locking Nuts Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/11/1986 Make: The Boeing Company Model: 737-100 Series | 737-200 Series | 737-200C Series | 737-300 Series | 737-400 Series | 737-500 Series...Show more Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 86-18-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5385 AD NUMBER: 86-18-04 SUBJECT HEADING: BOEING Model 737 Series Airplanes ACTION: SUMMARY: DATES: Effective September 11, 1986. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_86-18-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 86-18-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: BOEING Model 737 Series Airplanes Subject: Self-Locking Nuts Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 09/11/1986 Make: The Boeing Company Model: 737-100 Series | 737-200 Series | 737-200C Series | 737-300 Series | 737-400 Series | 737-500 Series...Show more Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 86-18-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5385 AD NUMBER: 86-18-04 SUBJECT HEADING: BOEING Model 737 Series Airplanes ACTION: SUMMARY: DATES: Effective September 11, 1986. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2025-02-02 Recurring
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: cracks in the frame inner chord and web at station (STA) 727 between S-11L and S-13L, which could result in the inability of a principal structural element to sustain limit load, and adversely affe...
2023-13-12 Recurring
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: premature aging of certain passenger chemical oxygen generators, which could fail to deliver oxygen during an emergency, possibly resulting in injury to the airplane occupants.
2023-12-13
final ruleAirworthiness Directives; The Boeing Company Airplanes
Unsafe Condition: Radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 5G C-Band. This interference can cause other airp...
2023-10-02
final ruleAirworthiness Directives; Transport and Commuter Category Airplanes
Unsafe Condition: Radio altimeter anomalies that are undetected by the automation or pilot, particularly close to the ground (e.g., landing flare), could lead to loss of continued safe flight and landing. Additional...