# AD 2005-19-10: Fuel control units (FCUs) - Type: Airworthiness directive - Status: Historical - Products: Turbomeca Arrius 2F - Effective: October 3, 2005 - Published: September 16, 2005, 70 FR 54622–54624 - Issued: September 9, 2005 - Issued as: Final rule; request for comments - Superseded by: [AD 2007-11-06](https://openairdocs.org/ad/2007-11-06) - Product type: Engine - Amendment: 39-14275 - Docket: FAA-2005-22430 (https://www.regulations.gov/docket/FAA-2005-22430) - Project: 2005-NE-34-AD - Registered aircraft: 62 may be affected, by airframe or engine model (OpenAirDocs) - Official PDF: https://openairdocs.org/files/sha256/a8/34/a8340cc8aab25926b06b288adcc8795db2388d3100ceeebbadfc22ef03d5b635 (from https://www.govinfo.gov/content/pkg/FR-2005-09-16/pdf/05-18322.pdf) - Federal Register: https://www.federalregister.gov/documents/2005/09/16/05-18322/airworthiness-directives-turbomeca-arrius-2-f-turboshaft-engines - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/88952B887F210C988625707E005944F2.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/2005-19-10 ## Summary The FAA is adopting a new airworthiness directive (AD) for Turbomeca Arrius 2 F turboshaft engines. This AD requires removing from service certain serial number (SN) fuel control units (FCUs) or replacing the constant delta pressure diaphragm in those FCUs. This AD results from a report of an accident in July 2005 involving a Eurocopter EC120B helicopter. We are issuing this AD to prevent an uncommanded engine in-flight shutdown on a single-engine helicopter, resulting in a forced autorotation landing or an accident. ## The airworthiness directive Under 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: ## Rule preamble ### Dates Effective October 3, 2005. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of October 3, 2005. We must receive any comments on this AD by November 15, 2005. ### Addresses Use one of the following addresses to comment on this AD: • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically. • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically. • Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001. • Fax: (202) 493-2251. • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. Contact Turbomeca, 40220 Tarnos, France; telephone +33 05 59 74 40 00, fax +33 05 59 74 45 15, for the service information identified in this AD. ### For further information contact Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7175; fax (781) 238-7199. ### SUPPLEMENTARY INFORMATION The Direction Generale de L'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on Turbomeca Arrius 2 F turboshaft engines. The DGAC advises that a Eurocopter EC120B helicopter powered by an Arrius 2 F turboshaft engine experienced an uncommanded in-flight engine shutdown. An increase in fuel flow led to an increase in gas generator and power turbine speeds. Turbine blades separated from the disk due to the overspeed. Turbomeca determined that the fuel flow increase was caused by an improperly assembled and subsequent failure of the constant delta pressure (delta P) diaphragm in the FCU. Only certain types of constant delta P diaphragms have been identified as being capable of being improperly assembled. Engine serial numbers that may have this type of constant delta P diaphragm are listed in Turbomeca Alert Mandatory Service Bulletin (MSB) No. A319 73 4825, dated August 3, 2005. The manufacturer is making spare FCUs available as fast as possible and has established a rotable pool of spares. After we reviewed the Turbomeca SB, we concluded that using the Turbomeca rotable pool of spares as soon as practicable effectively manages the risk of another failure of the uninspected engine population. To this end, we are requiring that FCUs identified in the Turbomeca SB be replaced as soon as practicable but not to exceed February 28, 2006. Because the practicable compliance time may be quite short for some operators and the rotable pool requires consistent participation, we are issuing this AD as final rule; request for comments. ### Relevant Service Information We have reviewed and approved the technical contents of Turbomeca Alert MSB No. A319 73 4825, dated August 3, 2005. That MSB lists the affected FCUs by SN and describes procedures for removing affected FCUs from service or replacing constant delta P diaphragms in those FCUs. The DGAC classified this service bulletin as mandatory and issued AD No. F-2005-143, dated August 17, 2005, and AD No. F-2005-143 R1, dated August 31, 2005, in order to ensure the airworthiness of these Arrius 2 F turboshaft engines in France. ### Bilateral Airworthiness Agreement This engine model is manufactured in France and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Under this bilateral airworthiness agreement, the DGAC kept the FAA informed of the situation described above. We have examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States. ### FAA's Determination and Requirements of this AD The unsafe condition described previously is likely to exist or develop on other Turbomeca Arrius 2 F turboshaft engines of the same type design. We are issuing this AD to prevent an uncommanded engine in-flight shutdown on a single-engine helicopter, resulting in a forced autorotation landing or an accident. This AD requires removing from service certain SN FCUs or replacing the constant delta P diaphragm in those FCUs. You must use the service information described previously to perform the actions required by this AD. ### FAA's Determination of the Effective Date Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists for making this amendment effective in less than 30 days. ### Comments Invited This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to send us any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. FAA-2005-22430; Directorate Identifier 2005-NE-34-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it. We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of the DMS Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov. ### Examining the AD Docket You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them. ### 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. ### 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 a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E34NE](https://openairdocs.org/tcds/E34NE): Safran Helicopter Engines S.A.; names 1 of 8 models: Arrius 2F ## 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: 62 (0 by airframe model, 62 by engine model) - Makers: Eurocopter 60, Airbus Helicopters 1, Eurocopter France 1 Models with the most aircraft: - [Turbomeca ARRIUS-2F](https://openairdocs.org/engine/turbomeca-arrius-2f): 62 aircraft (engine model) All 1 models: https://openairdocs.org/ad/2005-19-10/models.md Every aircraft: https://openairdocs.org/ad/2005-19-10/aircraft.md ## Related documents - [AD 2007-11-06](https://openairdocs.org/ad/2007-11-06): Constant delta pressure (delta P) diaphragm · Turbomeca Arrius 2F. Effective Jun 26, 2007. Supersedes this AD - [Proposed rule FAA-2005-22430](https://openairdocs.org/proposed/FAA-2005-22430): Notice of proposed rulemaking (NPRM), published Jan 17, 2007 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.