AD 2009-08-08R1

AD Final Rules - 2009-08-08R1.pdf
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AD Number:
2009-08-08R1
Document Type:
AD Final Rules
Docket Number:
FAA-2009-0302
Subject Heading:
Airworthiness Directives; Turbomeca ARRIEL 1B, 1D, 1D1, 2B, and 2B1 Turboshaft Engines
Subject:
PT Blades
Status:
Current
Citation:
Federal Register: April 2, 2010 (Volume 75, Number 63)
Citation Publish Date:
04/02/2010
Effective Date:
05/07/2010
Make:
Turbomeca S.A.
Model:
Arriel 1B | Arriel 1D | Arriel 1D1 | Arriel 2B | Arriel 2B1
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
2009-08-08
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
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[Federal Register: April 2, 2010 (Volume 75, Number 63)]


[Rules and Regulations]


[Page 16664-16666]


From the Federal Register Online via GPO Access [wais.access.gpo.gov]


[DOCID:fr02ap10-10]


––––––––––––––––––––––––––––––––––


DEPARTMENT OF TRANSPORTATION


Federal Aviation Administration


14 CFR Part 39


[Docket No. FAA-2009-0302; Directorate Identifier 2009-NE-09-AD; Amendment 39-16245;


AD 2009-08-08R1]


RIN 2120-AA64


Airworthiness Directives; Turbomeca ARRIEL 1B, 1D, 1D1, 2B, and 2B1 Turboshaft Engines


AGENCY:
 
Federal Aviation Administration (FAA), DOT.


ACTION:
 
Final rule.


––––––––––––––––––––––––––––––––––


SUMMARY:
 
We are revising an existing airworthiness directive (AD) for the products listed above.


This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation


authority of another country to identify and correct an unsafe condition on an aviation product. The


MCAI describes the unsafe condition as:


During production of Arriel 1 and Arriel 2 Power Turbine (PT) wheels, geometric


non-conformances on blade fir tree roots have been detected by Turboméca.


Potentially non-conforming PT blades have been traced as having been installed on


Module M04 (PT) listed in Mandatory Service Bulletin (MSB) A292 72 0827 for


Arriel 1 engines and A292 72 2833 for Arriel 2 engines.


The geometric non-conformities of the blades may potentially lead to a reduction in


the fatigue resistance of PT blades to a lower level than their authorized in service use


limit. This reduction of fatigue resistance can potentially result in blade release, which


could cause an uncommanded in-flight shutdown.


We are issuing this AD to prevent release of PT blades, which could result in an uncommanded in-


flight shutdown and emergency autorotation landing.


DATES:
 
This AD becomes effective May 7, 2010. The Director of the Federal Register approved the


incorporation by reference of certain publications listed in this AD as of May 7, 2010.


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.
2


FOR FURTHER INFORMATION CONTACT:
 
Kevin Dickert, Aerospace Engineer, Engine


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


Burlington, MA 01803; e-mail: kevin.dickert@faa.gov; telephone (781) 238-7117, fax (781) 238-


7199.


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 23, 2009 (74 FR 68194). That NPRM proposed to correct an unsafe condition for the


specified products. The MCAI states:


Since issuance of initial version of AD 2009-0112 additional information is available:


–The list of Modules M04 concerned by the restriction of the cycle use limit of these


PT blades has been updated again: The serial numbers of Modules M04 which have


been retrofitted are crossed out. However, no new affected Modules M04 have been


identified. See figure 1 of the referenced Turboméca MSB.


–Additional testing and analysis had been carried out by Turboméca which allows


increasing the cyclic use limit of these PT blades to 5 000 flight cycles.


Therefore this AD revises AD 2009-0112 and requires establishing the cyclic use limit


of these PT blades to 5 000 flight cycles.


For PT blades having reached a number of flight cycles superior or equal to 5 000,


removal of Module M04, or PT wheel assembly, or PT blades is required prior to next


flight.


Comments


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


comments on the NPRM or on the determination of the cost to the public.


Conclusion


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


adopting the AD as proposed.


Differences Between This AD and the MCAI or Service Information


We have reviewed the MCAI and related service information and, in general, agree with their


substance. But we required different actions in this AD from those in the MCAI in order to follow


FAA policies. Any such differences are described in a separate paragraph of the AD. These


requirements take precedence over the actions copied from the MCAI.


Costs of Compliance


Based on the service information, we estimate that this AD will affect about 10 products of U.S.


registry. We also estimate that it will take about 8 work-hours per product to comply with this AD.