AD 2013-08-22

AD Final Rules - 2013-08-22.pdf
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AD Number:
2013-08-22
Document Type:
AD Final Rules
Docket Number:
FAA-2012-1131
Subject Heading:
Airworthiness Directives; Turbomeca S.A. Turboshaft Engines
Subject:
Tachometer's unit cycle-counting feature
Status:
Current
Citation:
Federal Register Volume 78, Number 78 (Tuesday, April 23, 2013)
Citation Publish Date:
04/23/2013
Effective Date:
05/28/2013
Make:
Turbomeca S.A.
Model:
Arriel 1A1 | Arriel 1A2 | Arriel 1B | Arriel 1C | Arriel 1C1 | Arriel 1C2 | Arriel 1D | Arriel 1D1 ...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
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[Federal Register Volume 78, Number 78 (Tuesday, April 23, 2013)]


[Rules and Regulations]


[Pages 23830-23832]


From the Federal Register Online via the Government Printing Office [www.gpo.gov]


[FR Doc No: 2013-09349]


––––––––––––––––––––––––––––––––––


DEPARTMENT OF TRANSPORTATION


Federal Aviation Administration


14 CFR Part 39


Docket No. FAA-2012-1131; Directorate Identifier 2012-NE-34-AD; Amendment 39-17440; AD


2013-08-22]


RIN 2120-AA64


Airworthiness 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 certain Turbomeca S.A. Arriel


1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K1, 1S, and 1S1 turboshaft engines. This AD requires


daily post-flight checks of the engine tachometer's unit cycle-counting feature. This AD also requires


ground-run functional checks within every 1,000 operating hours. This AD was prompted by detailed


analysis and review of the accuracy of the engine's tachometer cycle-counting feature. We are issuing


this AD to prevent uncontained engine failure and damage to the helicopter.


DATES:
 
This AD becomes effective May 28, 2013.


ADDRESSES:
 
The Docket Operations office is located at Docket Management Facility, U.S.


Department of Transportation, 1200 New Jersey Avenue SE., West Building Ground Floor, Room


W12-140, Washington, DC 20590-0001.


FOR FURTHER INFORMATION CONTACT:
 
Sanjana Murthy, Aerospace Engineer, Engine


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


Burlington, MA 01803; phone: 781-238-7750; fax: 781-238-7199; email: sanjana.murthy@faa.gov.


SUPPLEMENTARY INFORMATION:


Discussion


We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD


that would apply to the specified products. That NPRM was published in the Federal Register on


December 11, 2012 (77 FR 73557). That NPRM proposed to correct an unsafe condition for the


specified products. The mandatory continuing airworthiness information (MCAI) states:
2


Following detailed analysis and review of in-service feedback performed by


Turbomeca on the Arriel 1 engines, the chapter 05-10 Airworthiness Limitation


Section (ALS) of Arriel 1 Maintenance Manuals has been updated in order to clarify


the definition and update the requirements relative to the cycle counting aid system


(modification introduced in production by Turbomeca modification TU207 or TU243


and in-service, respectively, by Turbomeca Service Bulletin (SB) 292 80 0190 or SB


292 80 0168), add associated maintenance tasks, and modify the Power Turbine (PT)


partial cycle counting method.


The SBs referenced above introduced the tachometer. The tachometer's cycle-counting feature, in


some instances, produced results inconsistent with ground run checks. The inaccurate cycle-counting


results of the tachometer can lead to exceeding life limits on critical rotating parts, which can cause


uncontained engine failure and damage to the helicopter.


Comments


We gave the public the opportunity to participate in developing this AD. We received no


comments on the NPRM (77 FR 73557, December 11, 2012).


Actions Since We Issued the Proposed Rule


Since we issued the NPRM (77 FR 73557, December 11, 2012), the European Aviation Safety


Agency (EASA) issued revised MCAI (EASA AD 2012-0187R2, dated December 6, 2012), which


states that for affected engines that have a tachometer installed, but the tachometer is not used to


count cycles, then no further action is required.


Changes to Actions and Compliance Section of This AD


We evaluated the revised MCAI (EASA AD 2012-0187R2, dated December 6, 2012), and we


agree that for affected engines that have a tachometer installed, but the tachometer is not used to


count cycles, then no further compliance action is required. We changed paragraph (e) of the final


rule by inserting a new paragraph (e)(1) to read:


''(1) If a tachometer is installed on the engine, but is not used to count cycles, then no further


action is required.''


We also changed paragraph (e)(2) of this AD to clarify the objective of the daily check. The


objective is not only to compare the cycle-count values from the tachometer and the daily check, but


also to verify that they agree. The NPRM (77 FR 73557, December 11, 2012) stated:


''During the post flight maintenance inspection after the last flight of each day, compare the


cycles counted by the engine's tachometer unit with the cycles counted by the primary counting


method.''


The changed paragraph in this AD states:


''During the post-flight maintenance inspection after the last flight of each day, verify that the


cycles counted by the engine's tachometer unit agree with the cycles counted by the primary counting


method.''


We also changed paragraph (e)(4) of this AD to clearly state that the ground-run functional


check required every 1,000 operating hours is in addition to the daily inspections required by this


AD. The NPRM (77 FR 73557, December 11, 2012) stated:


''If the engine tachometer cycle-counting feature remains accurate, then every 1,000 operating


hours, perform a ground-run functional check of the tachometer unit cycle-counting feature.''


The changed paragraph in this AD states:


''If the engine tachometer cycle-counting feature remains accurate, then every 1,000 operating


hours, perform a ground-run functional check of the tachometer unit cycle-counting feature in