DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[4910-13-P] 

[Docket No. F AA-2015-3805; Directorate Identifier 2015-NE-28-AD; Amendment 

39-18389; AD 2016-03-021 

RIN 2120-AA64 

Ainvorthiness Directives; Turbomeca S.A. Turboshaft Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new airworthiness directive (AD) for all Turbomeca 

S.A. ARRlEL 2C, 2Cl, 2C2, 2S l , and 2S2 turboshaft engines with modification TU34 or 

TU34A installed. This AD requires inspecting the torque conformation box (TCB) for 

correct resistance values and removing TCBs that fail inspection before further flight. 

This AD was prompted by TCB failures. We are issuing this AD to prevent failure of the 

TCB, loss of engine thrust control, and damage to the helicopter. 

DATES: This AD becomes effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

The Director of the Federal Register approved the incorporation by reference of a 

certain publication listed in this AD as of [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: For service information identified in this 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, 1200 District 

Avenue, Burlington, MA. For information on the availability of this material at the FAA, 
call 78 1-238-7125. It is also available on the Internet at http://www.regulations.gov by 

searching for and locating Docket No. fAA-2015-3805. 

Examining the AD Docket 

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

searching for and locating Docket No. F AA-20 15-3805, or in person at the Docket 

Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal 

holidays. The AD docket contains this 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 Document 

Management Facili ty, U.S. Department ofTransportation, Docket Operations, M-30, 

West Building Ground floor, Room Wl2- 140, 1200 New Jersey Avenue SE., 

Washington, DC 20590. 

FOR FURTHER INFORMATION CONTACT: Brian Kierstead, Aerospace Engineer, 

Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 District Avenue, 

Burlington, MA 01803; phone: 78 1-238-7772; fax: 781-238-7199; email: 

brian.kierstead@faa.gov. 

SU PPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed rulemaking (NPRM) to amend 14 CfR part 39 by 

adding an AD that would apply to the specified products. The NPRM was published in 

the Federal Register on November 5, 20 15 (80 FR 68475). The NPRM proposed to 

con·ect an unsafe condition for the specified products. The MCAI states: 

Several cases of torque confom1ation box (TCB) fai lures have 

been reported on engines incorporating mod TU34 or mod TU34A. 

Investigation concluded that these failures were caused by cracks 

on soldered joints ofTCB resistors. 

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Comments 

This condition, if not corrected, could lead to limited power 

availability in a One Engine Inoperative (OEI) case, possibly 

resulting in reduced control ofthe helicopter. 

We gave the public the opportunity to participate in developing this AD. We 

received no comments on the NPRM (80 FR 68475, November 5, 20 15). 

Conclusion 

We reviewed the available data and determined that air safety and the public 

interest require adopting this AD as proposed. 

Related Service I nformation under 1 CFR Part 51 

Turbomeca S.A. has issued Mandatory Service Bulletin (MSB) No. 292 72 2860, 

Version A, dated July 15,2015. The MSB descri bes procedures for checking TCB 

resistance values. 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 or this fi nal rule. 

Costs of Compliance 

We estimate that this AD affects 300 engines installed on helicopters of U.S. 

registry. We estimate that it would take about I hour to perform an inspection. We also 

estir11ate that 20% of these engines would fail the inspection and require TCB removal, 

which would take about I hour. The average labor rate is $85 per hour. Based on these 

figures, we estimate the cost of this AD on U.S. operators to be $30,600. 

Authority for· T his Rulemaking 

Title 49 of the United States Code specifies the f AA's authority to issue rules on 

aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. 

"Subtille VII: Aviation Programs," describes in more detail the scope of the Agency's 

authority. 

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We are issuing this rulcmaking under the authori ty described in "Subtitle VII, 

Part A, Subpart HI, Section 4470 1: General requirements." Under that section, Congress 

charges the FAA with promoting safe flight of civil a ircraft in air commerce by 

prescribing regulations for practices, methods, and procedures the Admi nistrator 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 rul cmaking action. 

Regulatory Findings 

We determined that this AD will not have federalism implications under 

Executi ve 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 this AD: 

(I) Js not a "significant regulatory action" under Executi ve Order 12866, 

(2) Is not a "significant rul e" under the DOT Regul atory Policies and Procedures 

( 44 FR I I 034, February 26, 1979), 

(3) Will not affect intrastate aviati on in Alaska to the extent that it j ustifies 

making a regulatory distinction, and 

(4) Will not have a significant economic impact, positive or negative, on a 

substantia l number of small entities under the cri teria of the Regulatory Flexibility Act. 

List of Sub,iects in 14 CFR Part 39 

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

Adoption of the Amendment 

Accordingly, under the autho rity delegated to me by the Administrator, the FAA 

amends 14 CFR part 39 as follows: 

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PART 39- AIRWORTHINESS DIRECTIVES 

1. The authority citation for part 39 continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40 113, 4470 1. 

§ 39.13 [Amended) 

2. The FAA amends§ 39.13 by adding the following new airwo rthiness directive 

(AD): 

2016-03-02 Turbomeca S.A.: Amendment 39- 18389; Docket No. F J\J\-20 15-3805; 

Directorate Identi-fier 2015-NE-28-AD. 

(a) Effective Date 

This AD becomes effective (INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Turbomeca S.A. ARRIEL 2C, 2C I, 2C2, 2S I, and 2S2 

turboshaft engines with modification TU34 or TU34A installed. 

(d) Reason 

This AD was prompted by torque conformation box (TCB) fai lures. We are 

issuing this AD to prevent failure ofthe TCB, loss of engine thrust control, and damage 

to the helicopter. 

(e) Actions and Compliance 

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

(I) Withi n 600 engine flight hours (EFT-Is) or 6 months after the effective date of 

this AD, whichever occurs first, check the resistance values on the TCB. Use 

Accomplishment Instructions, paragraph 2.3.2 ofTurbomeca S.A. Mandatory Service 

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Bull etin 292 72 2860, Version A, dated July 15, 2015, to do the inspection. Repeat this 

inspection every 600 EFHs since last inspection. 

(2) Remove before further flight any TCB that fails the inspection required by 

paragraph (e)( I) of this AD. 

(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 Brian Kierstead, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 

District Avenue, Burlington, MA 01803; phone: 781-238-7772; fax: 781-238-7199; 

email: brian.kiersteacl@ faa.gov. 

(2) Refer to MCAI European Aviation Safety Agency AD 2015-0 177, dated 

August 25,2015, 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 Docket No. 

F AA-20 15-3805. 

(h) Material Incorporated by Reference 

( I) The Director of the Federal Register approved the incorporation by reference 

(1BR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 erR 

part 5 1. 

(2) You must use this service information as applicable to do the actions required 

by this AD, unless the AD specifies otherwise. 

(i) Turbomeca S.A. Mandatory Service Bulletin No. 292 72 2860, Version A, 

dated July 15,2015. 

(ii) Reserved. 

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(3) f-or Turbomeca S.A. service information identified in this AD, contact 

Turbomeca S.A., 40220 Tarnos, France; phone: 33 (0)5 59 74 40 00; fax : 33 (0)5 59 74 

45 15. 

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

Directorate, 1200 District Avenue, Burlington, MA. For information on the availability of 

this material at the FAA, call 781-238-7 125. 

(5) You may view this service information at the National Archives and Records 

Administration (NARA). For information on the availability of this material at NARA, 

call 202-741-6030, or go to: http://www.archives.gov/federal-register/c fr/ibrlocations.htrnl. 

Issued in Burli ngton, Massachusetts, on f-ebruary 2, 2016. 

Colleen M. D"Aicssandro, 

Manager, Engine & Propeller Directorate. 

Aircraft Certification Service. 

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