[Docket No. FAA-2015-3753; Directorate Identifier 2015-NE-26-AD] 

RlN 2120-AA64 

Airworthiness Directives; Turbomeca S.A. Turboshaft Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking (NPRM). 

SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain 

Turbomeca S.A. Arriel2B, 2Bl, 2C, 2Cl, 2C2, 2D, 2E, 2Sl, and 2S2 turboshaft engines. 

This proposed AD was prompted by a report of an uncommanded in-flight shutdown of 

an Arriel 2 engine caused by rupture of the 41-tooth gear, which forms part of the bevel 

gear in the engine accessory gearbox (AGB). This proposed AD would require inspection, and, depending on the results, removal of the engine AGB. We are proposing 

this AD to prevent failure of the engine AGB, which could lead to in-flight shutdown, 

damage to the engine, and damage to the aircraft. 

DATES: We must receive comments on this proposed AD by [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: You may send comments by any ofthe following methods: 

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the 

instructions for submitting comments. 
Monday through Friday, except Federal holidays. 

• Fax: 202-493-2251. 

For service infmmation identified in this proposed AD, contact Turbomeca S.A., 

40220 Tarnos, France; phone: 33 0 5 59 74 40 00; fax: 33 0 5 59 74 45 15. You may view 

this service information at the FAA, Engine & Propeller Directorate, 12 New England 

Executive Park, Burlington, MA. For information on the availability of this material at 

the FAA, call781-238-7125. 

Examining the AD Docket 

You may examine the AD docket on the Internet at http://www.regulations.gov by 

searching for and locating Docket No. F AA-20 15-3753; or in person at the Docket 

Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 

holidays. The AD docket contains this proposed AD, the mandatory continuing 

airworthiness information (MCAI), the regulatory evaluation, any comments received, 

and other information. The address for the Docket Office (phone: 800-647-5527) is in the 

ADDRESSES section. Comments will be available in the AD docket shortly after receipt. 

FOR FURTHER INFORMATION CONTACT: Philip Haberlen, Aerospace Engineer, 

Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England 

Executive Park, Burlington, MA 01803; phone: 781-238-7770; fax: 781-238-7199; email: 

philip.haberlen@faa.gov. 

2 
Include "Docket No. FAA-2015-3753; Directorate Identifier 2015-NE-26-AD" at the 

beginning of your comments. We specifically invite comments on the overall regulatory, 

economic, environmental, and energy aspects ofthis proposed AD. We will consider all 

comments received by the closing date and may amend this proposed AD based on those 

comments. 

We will post all comments we receive, without change, to 

http://www.regulations.gov, including any personal infom1ation you provide. We will 

also post a report summarizing each substantive verbal contact with FAA personnel 

concerning this proposed AD. 

Discussion 

The European Aviation Safety Agency (EASA), which is the Technical Agent for 

the Member States ofthe European Community, has issued EASA AD 2015-0162, dated 

August 6, 2015 (refen·ed to hereinafter as "the MCAI''), to correct an unsafe condition for 

the specified products. The MCAI states: 

An uncommanded in-flight shut-down (IFSD) of an ARRIEL 2 

engine was reported, caused by rupture of the 41-tooth gear, which 

forms part of the bevel gear of the accessory gearbox (module 

MOl). The subsequent investigation revealed that wear on the 

housing of the front bearing of this gear was a major contributor to 

this rupture. In addition, the investigation showed that this wear 

mechanism had resulted in positive Spectrometric Oil Analysis 

(SOA) indications before the event. 

3 
FAA-2015-3753. 

Related Service Information under 1 CFR Part 51 

Turbomeca S.A. has issued Mandatory Service Bulletin No. 292 72 2861, Version 

A, dated April 24, 2015. The service information describes procedures for inspecting the 

engine AGB. This service information is reasonably available because the interested 

parties have access to it through their normal course of business or by the means 

identified in the ADDRESSES section of this document. 

FAA's Determination and Requirements ofThis Proposed AD 

This product has been approved by the aviation authority of France, and is 

approved for operation in the United States. Pursuant to our bilateral agreement with the 

European Community, EASA has notified us ofthe unsafe condition described in the 

MCAI and service information referenced above. We are proposing this AD because we 

evaluated all information provided by EASA and determined the unsafe condition exists 

and is likely to exist or develop on other products of the same type design. This proposed 

AD would require inspection, and, depending on the results, removal of the engine AGB. 

Costs of Compliance 

We estimate that this proposed AD affects 250 engines installed on aircraft of 

U.S. registry. We also estimate that it would take about 0.5 hours per engine to comply 

with the initial inspection requirement in this proposed AD and about 2 hours per engine 

4 
Title 49 of the United States Code specifies the FAA's authority to issue rules on 

aviation safety. Subtitle 1, 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 Vll, 

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 determined that this proposed AD would not have federalism implications 

under Executive Order 13132. This proposed AD would 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 

govemment. 

For the reasons discussed above, I certify this proposed regulation: 

(1) Is not a "significant regulatory action" under Executive Order 12866, 

5 
(4) 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. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. 

The Proposed Amendment 

Accordingly, under the authority delegated to me by the Administrator, the FAA 

proposes to amend 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. The FAA amends§ 39.13 by adding the following new airworthiness directive 

(AD): 

Turbomeca S.A.: Docket No. FAA-2015-3753; Directorate Identifier 2015-NE-26-AD. 

(a) Comments Due Date 

We must receive comments by [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

None. 

6 
(d) Reason 

This AD was prompted by a report of an uncommanded in-flight shutdown of an 

Arriel 2 engine caused by rupture of the 41-tooth gear, which forms part of the bevel gear 

in the engine AGB. We are issuing this AD to prevent failure of the engine AGB, which 

could lead to in-flight shutdown, damage to the engine, and damage to the aircraft. 

(c) Actions and Compliance 

Comply with this AD within the compliance times specified, unless already done. 

(1) Initial Spectrometric Oil Analysis (SOA) 

(i) Perform an initial SOA within the compliance times given in paragraph 

(e)(l)(i)(A) or (e)(1)(i)(B) ofthis AD: 

(A) If the engine AGB has less than 800 engine hours (EHs) since new or since 

last overhaul, do an initial SOA before exceeding 850 EHs since new or since last 

overhaul. 

(B) If the engine AGB has 800 EHs or more since new or since last overhaul, or if 

the EHs are unknown, do an initial SOA within 50 EHs after the effective date of this 

AD. 

(C) Use paragraphs 2.4.2.1 and 2.4.2.2 ofTurbomeca S.A. Mandatory Service 

Bulletin (MSB) No. 292 72 2861, Version A, dated April 24, 2015, to perform the SOA 

required by paragraph (e) ofthis AD. 

7 
within 100 EHs time since last analysis (TSLA). 

(ii) If the aluminum concentration determined from the most recent SOA is 

between 0.8 PPM and 1.4 PPM, inclusive, repeat the SOA required by paragraph (e) of 

this AD within 50 EHs TSLA. Do not perform draining before doing the next SOA. 

(iii) If the aluminum concentration determined from the most recent SOA is 

greater than 1.4 PPM, remove the engine AGB from service within 50 EHs TSLA. 

(f) Alternative Methods of Compliance (AMOCs) 

The Manager, Engine Certification Office, FAA, may approve AMOCs for this 

AD. Use the procedures found in 14 CFR 39.19 to make your request. You may email 

your request to: ANE-AD-AMOC@faa.gov. 

(g) Related Information 

(1) For more information about this AD, contact Philip Haberlen, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 01803; phone: 781-238-7770; fax: 781-238-

71 99; email: philip.haberlen@faa.gov. 

(2) Refer to MCAI European Aviation Safety Agency AD 2015-0162, dated 

August 6, 2015, for more information. You may examine the MCAI in the AD docket on 

the Internet at http://www.regulations.gov by searching for and locating it in Docket No. 

FAA-2015-3753. 

8 
S.A., 40220 Tarnos, France; phone: 33 0 5 59 74 40 00; fax: 33 0 5 59 74 45 15. 

(5) You may view this service information at the FAA, Engine & Propeller 

Directorate, 12 New England Executive Park, Burlington, MA. For information on the 

availability of this material at the FAA, call 781-23 8-7125. 

Issued in Burlington, Massachusetts, on November 12, 2015. 

Colleen M. D' Alessandro, 

Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

9