# AD 2005-10-14: Main or combiner gearboxes - Type: Airworthiness directive - Status: Current - Products: Airbus Helicopters AS355E, AS355F, AS355F1, AS355F2 and AS355N - Effective: June 21, 2005 - Published: May 17, 2005, 70 FR 28188–28190 - Issued: May 9, 2005 - Issued as: Final rule - Supersedes: [AD 2004-01-51](https://openairdocs.org/ad/2004-01-51) - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-14091 - Docket: FAA-2005-20293 (https://www.regulations.gov/docket/FAA-2005-20293) - Project: 2004-SW-34-AD - Registered aircraft: 33 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/e9/4f/e94fbef9158d22d9360c269ce86251d34a4b77072e70d10b910982ef22d87085 (from https://www.govinfo.gov/content/pkg/FR-2005-05-17/pdf/05-9766.pdf) - Federal Register: https://www.federalregister.gov/documents/2005/05/17/05-9766/airworthiness-directives-eurocopter-france-model-as355e-f-f1-f2-and-n-helicopters - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A78BFB3B87C5811D86257004004EE386.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/2005-10-14 ## Summary This amendment supersedes an existing airworthiness directive (AD) for the specified Eurocopter France (ECF) model helicopters. That AD currently requires replacing certain main or combiner gearboxes with airworthy gearboxes. Further investigation has shown that the main gearbox is not affected, and this amendment requires replacing a certain combiner gearbox with a modified airworthy gearbox. This amendment is prompted by a report of a freewheel unit slipping resulting in an engine overspeed and shutdown. Also, this amendment is prompted by the conclusion of the investigation, which finds the freewheel slippage is due to the surface treatment applied to certain freewheel rollers in the combiner gearbox. The actions specified by this AD are intended to prevent an engine overspeed, an engine shutdown, and subsequent loss of control of the helicopter. ## The airworthiness directive 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: 1. The authority citation for part 39 continues to read as follows: 2. Section 39.13 is amended by removing Amendment 39-13495 (69 FR 9201, February 27, 2004), and by adding a new airworthiness directive (AD), to read as follows: 2005-10-14 Eurocopter France: Amendment 39-14091. Docket No. FAA-2005-20293; Directorate Identifier 2004-SW-34-AD. Supersedes AD 2004-01-51, Amendment 39-13495, Docket No. 2003-SW-56-AD. Applicability: Model AS355E, F, F1, F2, and N helicopters with a pre-MOD 077212 combiner gearbox that has 10 or less hours time-in-service installed, certificated in any category. Compliance: Before further flight, unless accomplished previously. To prevent an engine overspeed, an engine shutdown, and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, replace each pre-MOD 077212 combiner gearbox with a combiner gearbox modified by replacing the freewheel rollers in accordance with MOD 077212. Note 1: Eurocopter France Alert Telex No. 63.00.21 R2, dated February 4, 2004, pertains to the subject AD. (b) Performing paragraph (a) of this AD is terminating action for the requirements of this AD. (c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Safety Management Group, FAA, for information about previously approved alternative methods of compliance. (d) Special flight permits will not be issued. (e) This amendment becomes effective on June 21, 2005. Note 2: The subject of this AD is addressed in Direction Generale de L'Aviation Civile, France, AD No. F-2004-021, dated March 3, 2004. ## Rule preamble ### Dates Effective June 21, 2005. ### Addresses Examining the Docket: You may examine the docket that contains this AD, any comments, and other information on the Internet at http://dms.dot.gov, or at the Docket Management System (DMS), U.S. Department of Transportation, 400 Seventh Street SW., Room PL-401, on the plaza level of the Nassif Building, Washington, DC. ### For further information contact Uday Garadi, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Regulations and Guidance Group, Fort Worth, Texas 76193-0110, telephone (817) 222-5123, fax (817) 222-5961. ### SUPPLEMENTARY INFORMATION A proposal to amend 14 CFR part 39 by superseding AD 2004-01-51, Amendment 39-13495, Docket No. 2003-SW-56-AD (69 FR 9201, February 27, 2004), for the specified ECF model helicopters was published in the Federal Register on February 10, 2005 (70 FR 7059). The action proposed to require, before further flight, replacing each combiner gearbox pre-MOD 077212 that has logged 10 hours or less time-in-service with a combiner gearbox modified by replacing the free-wheel rollers. The Direction Generale De L'Aviation Civile (DGAC), the airworthiness authority for France, notified the FAA that an unsafe condition may exist on the specified model helicopters. The DGAC advises of a combiner gearbox freewheel slippage with resulting engine shutdown due to overspeed, which occurred during the single-engine phase of an acceptance flight at the Eurocopter works. ECF has issued Alert Telex No. 63.00.21 R2, dated February 4, 2004 (AT 63.00.21 R2). The Alert Telex describes the conclusion of the investigation that the freewheel slippage is due to the surface treatment applied to freewheel rollers, pre-MOD 077212. The freewheel rollers are located in the combiner gearbox; therefore, the main gearbox has been eliminated as the cause of this unsafe condition. The results of the investigation led ECF to cancel the cleaning procedure described in Alert Telex No. 63.00.21 R1, dated December 19, 2003, but to extend the effectivity of their instructions to all combiner gearboxes. Also, Alert Telex 63.00.21 R2 specifies modifying the combiner gearboxes at an approved repair station by replacing the freewheel rollers and after that recording the modification on the Equipment Log Card. The DGAC classified AT 63.00.21 R2 as mandatory and issued AD F-2004-021, dated March 3, 2004, to ensure the continued airworthiness of these helicopters in France. These helicopter models are manufactured in France and are type certificated for operation in the United States under the provisions of 14 CFR 21.29 and the applicable bilateral agreement. Pursuant to the applicable bilateral agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of these type designs that are certificated for operation in the United States. Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed. The FAA estimates that this AD will affect 104 helicopters of U.S. registry. The required actions will take about 1/2 work hour to determine applicability and 12 work hours to replace a gearbox at an average labor rate of $65 per work hour per helicopter. Required parts will cost approximately $97,000 per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $981,180, assuming 10 gearboxes are replaced. ### Regulatory Findings We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect 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. For the reasons discussed above, I certify that the regulation: 1. Is not a “significant regulatory action” under Executive Order 12866; 2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. We prepared an economic evaluation of the estimated costs to comply with this AD. See the DMS to examine the economic evaluation. ### Authority for This Rulemaking Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority. We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [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: 33 (33 by airframe model, 0 by engine model) - Makers: Aerospatiale 22, Eurocopter/France 4, Airbus Helicopters 3, Airbus Helicopter 1, Eurocopter 1, Eurocopter France 1, S N I A S 1 Models with the most aircraft: - [Aerospatiale AS 355F1](https://openairdocs.org/model/aerospatiale-as-355f1): 9 aircraft (airframe model) - [Aerospatiale AS 355F2](https://openairdocs.org/model/aerospatiale-as-355f2): 6 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 AS355N](https://openairdocs.org/model/airbus-helicopters-as355n): 2 aircraft (airframe model) - [Aerospatiale AS355F TWINSTAR](https://openairdocs.org/model/aerospatiale-as355f-twinstar): 2 aircraft (airframe model) - [Aerospatiale AS-355E TWIN STAR](https://openairdocs.org/model/aerospatiale-as-355e-twin-star): 1 aircraft (airframe model) - [Airbus Helicopter AS355F1](https://openairdocs.org/model/airbus-helicopter-as355f1): 1 aircraft (airframe model) - [S N I A S AS 355F](https://openairdocs.org/model/s-n-i-a-s-as-355f): 1 aircraft (airframe model) - [Aerospatiale AS355N](https://openairdocs.org/model/aerospatiale-as355n): 1 aircraft (airframe model) - [Eurocopter AS 355N](https://openairdocs.org/model/eurocopter-as-355n): 1 aircraft (airframe model) - [Airbus Helicopters AS355F2](https://openairdocs.org/model/airbus-helicopters-as355f2): 1 aircraft (airframe model) - [Eurocopter France AS355F2](https://openairdocs.org/model/eurocopter-france-as355f2): 1 aircraft (airframe model) All 13 models: https://openairdocs.org/ad/2005-10-14/models.md Every aircraft: https://openairdocs.org/ad/2005-10-14/aircraft.md ## Related documents - [AD 2004-01-51](https://openairdocs.org/ad/2004-01-51) (historical): Main or combiner gearbox · Airbus Helicopters AS355E, AS355F, AS355F1 and 2 more. Effective Mar 15, 2004. Replaced by this AD - [Proposed rule FAA-2005-20293](https://openairdocs.org/proposed/FAA-2005-20293): Notice of proposed rulemaking (NPRM), published Feb 10, 2005 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.