# AD 99-24-18: Tail Rotor Spider Plate Bearing - Type: Airworthiness directive - Status: Historical - Products: Eurocopter France AS-350B, AS-350B1, AS-350B2, AS-350B3, AS-350BA, AS-350D, AS355E, AS355F, AS355F1, AS355F2 and AS355N - Effective: December 15, 1999 - Published: November 30, 1999, 64 FR 66762–66763 - Issued: November 19, 1999 - Issued as: Final rule; request for comments - Superseded by: [AD 2001-17-32](https://openairdocs.org/ad/2001-17-32) - Product type: Aircraft, Rotorcraft - Amendment: 39-11443 - Docket: 99-SW-41-AD - Registered aircraft: 951 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/ab/d0/abd0360d3c48ff8ac0832a656f39e8963842c53fe05255320cc85dc0a82dc2f2 (from https://www.govinfo.gov/content/pkg/FR-1999-11-30/pdf/99-30797.pdf) - Federal Register: https://www.federalregister.gov/documents/1999/11/30/99-30797/airworthiness-directives-eurocopter-france-model-as-350b-b1-b2-b3-ba-and-d-and-as-355e-f-f1-f2-and-n - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/227735CEA1FBE24D86256A4D00664167.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/99-24-18 ## Summary This amendment supersedes an existing airworthiness directive (AD), applicable to Eurocopter France Model AS-350B, B1, B2, B3, BA, and D, and AS-355E, F, F1, F2, and N helicopters, that requires inspecting certain versions of the tail rotor spider plate bearing (bearing) for the proper rotational torque, axial play, and any brinelling of the bearing. This amendment has the same inspection requirements as the current AD. Also, this AD expands the applicability to include additional part numbers (P/N's) and reduces the initial and recurring inspection compliance times. This amendment is prompted by additional reports of deterioration of the bearing. The actions specified by this AD are intended to prevent seizure of the bearing, loss of tail rotor control, and subsequent loss of control of the helicopter. ## The airworthiness directive 99-24-18 EUROCOPTER FRANCE: Amendment 39-11443. Docket No. 99-SW-41-AD. Supersedes AD 99-09-06, Amendment 39-11139, Docket No. 98-SW-44-AD. Applicability: AS-350B, B1, B2, B3, BA, and D, and AS-355E, F, F1, F2, and N helicopters, with tail rotor spider assembly, part number (P/N) 350A33-2004-00, -01, -02, -03, -05, or 350A33-2009-00 or -01, installed, and which do not incorporate MOD 076551, certificated in any category. NOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification,alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated, unless accomplished previously. To prevent seizure of the tail rotor spider plate bearing (bearing), loss of tail rotor control, and subsequent loss of control of the helicopter, accomplish the following in accordance with the specified paragraphs of Eurocopter Service Bulletin (SB) 05.00.29, Revision 2, applicable to Model AS-350 helicopters, or SB 05.00.30, Revision 2, applicable to Model AS 355 helicopters, both dated September 29, 1999, as applicable. (a) Within 10 hours time-in-service (TIS), measure the rotational torque of the bearing using the operational procedure in paragraph 2.B.1) of the Accomplishment Instructions in the applicable SB. If the rotational load is equal to or greater than 300 grams, replace the pitch change spider plate assembly with an airworthy pitch change spider plate assembly before further flight. (b) At intervals not to exceed 50 hours TIS or at intervals not to exceed 6 months, whichever occurs first, measure the axial play and inspect for rotational binding or brinelling of the bearing using the operational procedure in paragraph 2.B.2) of the Accomplishment Instructions in the applicable SB. (c) If the bearing fails to meet the airworthiness criteria stated in paragraph 2.B.3)b) of the Accomplishment Instructions in the applicable SB, replace the pitch change spider plate assembly with an airworthy pitch change spider plate assembly before further flight. (d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Regulations Group, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Regulations Group. NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Regulations Group, Rotorcraft Directorate. (e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished. (f) The inspections and replacements, if necessary, shall be done in accordance with paragraph 2.B of Eurocopter SB 05.00.29, Revision 2, applicable to Model AS-350 helicopters, or Eurocopter SB 05.00.30, Revision 2, applicable to Model AS 355 helicopters, both dated September 29, 1999, as applicable. 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 American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, Rules Docket No. 99-SW-41-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (g) This amendment becomes effective on December 15, 1999. NOTE 3: The subject of this AD is addressed in Direction Generale De L'Aviation Civile (France) AD 1999-084-057(A)R2 and AD 1999-085-076(A)R2, both dated October 20, 1999. ## Rule preamble ### Supplementary information On April 14, 1999, the FAA issued AD 99-09-06, Amendment 39-11139 (64 FR 19881, April 23, 1999), to require inspecting the bearing for the proper rotational torque, axial play, and any brinelling of the bearing. That action was prompted by service difficulty reports citing the need to prematurely replace bearings due to wear and by two in-flight incidents of increased tail rotor vibration levels due to bearing wear. That condition, if not corrected, could result in seizure of the bearing, loss of tail rotor control, and subsequent loss of control of the helicopter. Since the issuance of that AD, the FAA has received additional reports of deterioration of the bearing affected by AD 99-09-06 and other bearings not covered by AD 99-09-06. Therefore, this AD expands the applicability to include additional bearing P/N's and to reduce the initial and recurring inspection compliance times. Eurocopter France has issued Service Bulletin (SB) 05.00.29,Revision 2, applicable to Model AS-350 series helicopters, and SB 05.00.30, Revision 2, applicable to Model AS-355 series helicopters, both dated September 29, 1999. These SB's specify a check of the bearing for rotational torque. The Direction Generale De L'Aviation Civile (DGAC), the airworthiness authority for France, classified these SB's as mandatory and issued AD's 1999-085-076(A)R2 and 1999-084-057(A)R2, both dated October 20, 1999, to ensure the continued airworthiness of these helicopters in France. Since an unsafe condition has been identified that is likely to exist or develop on other Eurocopter France Model AS-350B, B1, B2, B3, BA, and D, and AS-355E, F, F1, F2, and N helicopters of the same type design, this AD supersedes AD 99-09-06 (64 FR 19881, April 23, 1999). This AD has the same requirements as the current AD. This AD also expands the applicability to include additional P/N's 350A33-2004-00, -01 and -02, and 350A33-2009-00 and - 01, installed, and excludes a bearing which has MOD 076551 incorporated. This AD also revises the initial and recurring inspection compliance times. The actions are required to be accomplished in accordance with the SB's described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, including additional P/N's in the applicability, requiring an initial inspection within 10 hours time-in-service (TIS) to measure the bearing rotational torque, and inspecting the bearing for axial play or brinelling at intervals not to exceed 50 hours TIS or 6 months, whichever occurs first, are required and this AD must be issued immediately. Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. The FAA estimates that 507 helicopters will be affected by this AD, that it will take approximately 1 work hour to accomplish the inspection, and 4 work hours to replace a bearing, if required, and that the average labor rate is $60 per work hour. Required parts will cost approximately $60 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $182,520 to inspect all affected helicopters and to replace one bearing in each helicopter in the fleet. Comments Invited Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified underthe caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard onwhich the following statement is made: "Comments to Docket No. 99-SW-41-AD." The postcard will be date stamped and returned to the commenter. The regulations adopted herein will not impose substantial direct compliance costs on states or local governments or have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 13132, the FAA has not consulted with States or local authorities prior to the publication of this rule. The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034,February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. Adoption of the Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: PART 39 - AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 39.13 [Amended] 2. Section 39.13 is amended by removing Amendment 39-11139 (64 FR 19881, April 23, 1999), and by adding a new airworthiness directive (AD), Amendment 39-11443, to read as follows: ## 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 6 of 10 models: AS350B3, AS350B, 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/99-24-18/models.md Every aircraft: https://openairdocs.org/ad/99-24-18/aircraft.md ## Related documents - [AD 2001-17-32](https://openairdocs.org/ad/2001-17-32): Tail Rotor Pitch Change Spider Assembly · Airbus Helicopters AS355E, AS355F, AS355F1 and 9 more. Effective Oct 4, 2001. Supersedes this AD No proposed rule in this release led to it. 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, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB FTW00LA153](https://openairdocs.org/ntsb/FTW00LA153), May 24, 2000: Eurocopter AS350B2 (N350JG), Patterson, LA, substantial damage. Probable cause: the failure of the tail rotor spider bearing, the pilot's failure to follow the proper emergency procedures as stated in the helicopter's checklist by not performing a run-on landing, and the… --- 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.