# AD 81-18-01: Main Rotor Trunnions - Type: Airworthiness directive - Status: Historical - Products: Bell Helicopter Textron 206A, 206A-1 (OH-58A), 206B, 206B-1, 206L and 206L-1 - Effective: September 22, 1981 - Superseded by: [AD 81-18-01 R1](https://openairdocs.org/ad/81-18-01-R1) - Product type: Aircraft, Rotorcraft - Amendment: 39-4192 - Docket: 81-ASW-27 - Registered aircraft: 1,016 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/32D3F76DA30AE04C86256A4E0057758A.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/81-18-01 ## The airworthiness directive 81-18-01 BELL: Amendment 39-4192. Applies to Models 206A, 206B, 206A-1, 206B-1, 206L, and 206L-1 helicopters, equipped with main rotor trunnions, P/N 206-010-104-3, 206-011- 113-001, 206-011-120-001, 206-011-113-103, and 206-011-120-103, certificated in all categories (Airworthiness Docket No. 81-ASW-27). Compliance required as indicated. To prevent possible failure of the main rotor trunnion, P/N's 206-010-104-3, 206-011- 113-001, 206-011-120-001, 206-011-113-103, and 206-011-120-103, due to fatigue cracks, accomplish the following, unless already accomplished: a. Main rotor trunnions, P/N 206-011-120-001, with 1,100 or more hours' time in service on the effective date of this AD must be retired from service within the next 100 hours' time in service. b. Main rotor trunnions, P/N 206-011-120-001, with less than 1,100 hours' time in service on the effective date of this AD must be retired from service prior to or on attaining 1,200 hours' time in service.c. Main rotor trunnions, P/N 206-010-104-3, 206-011-113-001, and 206-011-120- 103, with 2,300 or more hours' time in service on the effective date of this AD must be retired from service within the next 100 hours' time in service. d. Main rotor trunnions, P/N 206-010-104-3, 206-011-113-001, and 206-011-120- 103, with less than 2,300 hours' time in service on the effective date of this AD must be retired from service prior to or on attaining 2,400 hours' time in service. e. Main rotor trunnions, P/N 206-011-113-103, with 4,700 or more hours' time in service on the effective date of this AD must be retired from service within the next 100 hours' time in service. f. Main rotor trunnions, P/N 206-011-113-103, with less than 4,700 hours' time in service on the effective date of this AD must be retired from service prior to or on attaining 4,800 hours' time in service. g. The helicopter may be flown in accordance with FAR 21.197 to a base where compliance with this AD can be performed. h. The retirement times, for the main rotor trunnions, established by this AD, are as follows: Part Number Service Life-Hours 206-011-120-001 1,200 206-010-104-3 2,400 206-011-113-001 2,400 206-011-120-103 2,400 206-011-113-103 4,800 (Bell Helicopter Textron Alert Service Bulletins 206-80-7, Rev. B, dated October 15, 1980, and 206L-80-9, Rev. B, dated October 15, 1980, pertain to this subject.) This amendment becomes effective September 22, 1981. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS H2SW](https://openairdocs.org/tcds/H2SW): Bell Textron Canada Limited; names 6 of 12 models: 206L, 206B, 206L-1, 206A, 206B-1, 206A-1 (OH-58A) ## 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: 1,016 (1,016 by airframe model, 0 by engine model) - Makers: Bell 828, Bell Helicopter Textron 178, Bell Helicopter Textron Canada 10 Models with the most aircraft: - [Bell 206B](https://openairdocs.org/model/bell-206b): 790 aircraft (airframe model) - [Bell Helicopter Textron 206L-1](https://openairdocs.org/model/bell-helicopter-textron-206l-1): 149 aircraft (airframe model) - [Bell Helicopter Textron 206B](https://openairdocs.org/model/bell-helicopter-textron-206b): 29 aircraft (airframe model) - [Bell 206A](https://openairdocs.org/model/bell-206a): 23 aircraft (airframe model) - [Bell Helicopter Textron Canada 206B](https://openairdocs.org/model/bell-helicopter-textron-canada-206b): 10 aircraft (airframe model) - [Bell 206A-1](https://openairdocs.org/model/bell-206a-1): 6 aircraft (airframe model) - [Bell 206L](https://openairdocs.org/model/bell-206l): 6 aircraft (airframe model) - [Bell 206B II](https://openairdocs.org/model/bell-206b-ii): 3 aircraft (airframe model) All 8 models: https://openairdocs.org/ad/81-18-01/models.md Every aircraft: https://openairdocs.org/ad/81-18-01/aircraft.md ## Related documents - [AD 81-18-01 R1](https://openairdocs.org/ad/81-18-01-R1): Trunnion ยท Bell Helicopter Textron Canada 206A, 206A-1 (OH-58A), 206B and 3 more. Effective Jan 15, 2002. Supersedes this AD - [Proposed rule 81-ASW-27](https://openairdocs.org/proposed/81-ASW-27): Notice of Proposed rulemaking (NPRM), published Sep 13, 2001 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.