# AD 86-15-10 R1: Main Rotor Arms & Gearbox Bars - Type: Airworthiness directive - Status: Historical - Products: Eurocopter France AS-350B, AS-350B1, AS-350B2, AS-350B3, AS-350BA, AS-350C, AS-350D, AS-350D1, AS355E, AS355F, AS355F1, AS355F2 and 1 more - Effective: March 22, 1990 - Superseded by: [AD 86-15-10 R2](https://openairdocs.org/ad/86-15-10-R2) - Product type: Aircraft, Rotorcraft - Amendment: 39-6514 - Docket: 86-ASW-22 - Registered aircraft: 951 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/722D4A1DADF8FF7B86256A4C005DAABC.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/86-15-10-R1 ## The airworthiness directive 86-15-10 R1 SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE (SNIAS): Amendment 39-5517 as revised by Amendment 39-6514. Docket No. 86-ASW-22. Applicability: Aerospatiale Model AS 350 and AS 355 series helicopters, certificated in any category. Compliance: Required as indicated, unless already accomplished. To prevent the failure of the main rotor head star arms and the main gearbox suspension bars, accomplish the following: (a) Within the next 10 hours' time in service after the effective date of this AD: (1) For Model AS 350 series helicopters, inspect the main rotor head components, the main gearbox suspension bars (struts), and the landing gear ground resonance prevention components (aft spring blades and hydraulic shock absorbers) in accordance with Service Bulletin (SB) 01.17a, paragraph CC.3. (2) For Model AS 355 series helicopters, inspect the main rotor head components, the main gearbox suspension bars (struts), and the landing gear ground resonance prevention components (aft spring blades and hydraulic shock absorbers) in accordance with SB 01.14a, paragraph CC.3. (b) Rework or replace damaged components in accordance with SB 01.17a or 01.14a (as applicable). (c) Repeat the inspections and rework of paragraphs (a) and (b) in intervals not to exceed 400 hours' time in service. (d) In the event the helicopter is subjected to a hard landing or to high surface winds, when parked without effective tiedown straps installed, repeat the inspections of paragraph (a) for the main rotor head star arms and the main gearbox suspension bars before further flight. (e) In the event of a landing which exhibits abnormal self-sustained dynamic vibrations (ground resonance type vibrations) repeat all the inspections of paragraph (a). (f) An alternate method of compliance with this AD, which provides an equivalent level of safety, may be used when approved by the Manager, Aircraft Certification Division, Federal Aviation Administration, Fort Worth, Texas 76193-0100, or by the Manager, Aircraft Certification Office, AEU-100, FAA, Europe, Africa, and Middle East Office, c/o American Embassy, Brussels, Belgium. (g) In accordance with Sections 21.197 and 21.199, flight is permitted to a base where the inspections required by this AD may be accomplished. The manufacturer's specifications and procedures shall be done in accordance with Aerospatiale SB 01.17a or 01.14a (as applicable). The incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a)(1). Copies may be obtained from Aerospatiale Helicopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75051, Attention: Customer Support. These documents may be examined in the Rules Docket at the Office of the Regional Counsel, Southwest Region, Federal Aviation Administration, Room 156, Building 3B, 4400 Blue Mound Road, Fort Worth, Texas 76106 or at the Office of the Federal Register, 1100 L Street, NW., Room 8401, Washington, D.C. This AD revises AD 86-15-10, Amendment 39-5517 (52 FR 13233; April 22, 1987), which became effective on April 22, 1987, as to all persons except those persons to whom it was made immediately effective by priority letter AD 86-15-10, issued July 30, 1986, which contained this amendment. This amendment (39-6514, AD 86-15-10 R1) becomes effective on March 22, 1990. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS H9EU](https://openairdocs.org/tcds/H9EU): Airbus Helicopters; names 8 of 10 models: AS350C, AS350B3, AS350B, AS350D1, AS350B2, AS350B1, AS350D, AS350BA - [TCDS H11EU](https://openairdocs.org/tcds/H11EU): Airbus Helicopters; names 5 of 6 models: AS355N, AS355F2, AS355F1, AS355E, AS355F ## 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: 951 (951 by airframe model, 0 by engine model) - Makers: Airbus Helicopters 362, Eurocopter 328, American Eurocopter 162, Aerospatiale 66, Eurocopter France 20, S N I A S 8, Eurocopter/France 4, Airbus Helicopter 1 Models with the most aircraft: - [Airbus Helicopters AS350B3](https://openairdocs.org/model/airbus-helicopters-as350b3): 291 aircraft (airframe model) - [Eurocopter AS 350 B3](https://openairdocs.org/model/eurocopter-as-350-b3): 167 aircraft (airframe model) - [Eurocopter AS 350 B2](https://openairdocs.org/model/eurocopter-as-350-b2): 146 aircraft (airframe model) - [American Eurocopter AS350B3](https://openairdocs.org/model/american-eurocopter-as350b3): 124 aircraft (airframe model) - [Airbus Helicopters AS 350B3](https://openairdocs.org/model/airbus-helicopters-as-350b3): 56 aircraft (airframe model) - [American Eurocopter AS350B2](https://openairdocs.org/model/american-eurocopter-as350b2): 38 aircraft (airframe model) - [Aerospatiale AS350BA](https://openairdocs.org/model/aerospatiale-as350ba): 18 aircraft (airframe model) - [Aerospatiale AS350B](https://openairdocs.org/model/aerospatiale-as350b): 13 aircraft (airframe model) - [Eurocopter AS 350 BA](https://openairdocs.org/model/eurocopter-as-350-ba): 13 aircraft (airframe model) - [Aerospatiale AS350B2](https://openairdocs.org/model/aerospatiale-as350b2): 11 aircraft (airframe model) - [Airbus Helicopters AS350B2](https://openairdocs.org/model/airbus-helicopters-as350b2): 10 aircraft (airframe model) - [Aerospatiale AS 355F1](https://openairdocs.org/model/aerospatiale-as-355f1): 9 aircraft (airframe model) - [Eurocopter France AS 350 B3](https://openairdocs.org/model/eurocopter-france-as-350-b3): 8 aircraft (airframe model) - [Eurocopter France AS350B2](https://openairdocs.org/model/eurocopter-france-as350b2): 8 aircraft (airframe model) - [Aerospatiale AS 355F2](https://openairdocs.org/model/aerospatiale-as-355f2): 6 aircraft (airframe model) - [S N I A S AS-350B ECUREUIL](https://openairdocs.org/model/s-n-i-a-s-as-350b-ecureuil): 5 aircraft (airframe model) - [Eurocopter/France AS355N TWINSTAR](https://openairdocs.org/model/eurocopter-france-as355n-twinstar): 4 aircraft (airframe model) - [Aerospatiale AS355F2 ECUREUIL](https://openairdocs.org/model/aerospatiale-as355f2-ecureuil): 3 aircraft (airframe model) - [Airbus Helicopters AS350BA](https://openairdocs.org/model/airbus-helicopters-as350ba): 2 aircraft (airframe model) - [Airbus Helicopters AS355N](https://openairdocs.org/model/airbus-helicopters-as355n): 2 aircraft (airframe model) All 36 models: https://openairdocs.org/ad/86-15-10-R1/models.md Every aircraft: https://openairdocs.org/ad/86-15-10-R1/aircraft.md ## Related documents - [AD 86-15-10 R2](https://openairdocs.org/ad/86-15-10-R2) (historical): Main Rotor Head Components, the Main Gearbox (MGB) Suspension Bars, and Ground Resonance Prevention System Components ยท Eurocopter France AS-350B, AS-350B1, AS-350B2 and 8 more. Effective May 23, 2000. Supersedes this AD Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB FTW01FA021](https://openairdocs.org/ntsb/FTW01FA021), Nov 17, 2000: Eurocopter AS350B2 (N126TV), Houston, TX, destroyed, 1 fatal. Probable cause: the pilot's failure to maintain obstacle clearance while maneuvering, which resulted in an in-flight collision with objects. Contributing factors were the dark night and low ceilings. --- 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.