AD 2007-26-20

AD Final Rules - 2007-26-20.pdf
Copy URL
Document Versions
 Feedback
DetailsAttachments/Public Comments
AD Number:
2007-26-20
Document Type:
AD Final Rules
Docket Number:
FAA-2007-27230
Subject Heading:
Airworthiness Directives; Pratt & Whitney (PW) PW4164, PW4168, and PW4168A Turbofan Engines
Subject:
LPT stage 4 disks
Status:
Current
Citation:
Federal Register: January 3, 2008 (Volume 73, Number 2)
Citation Publish Date:
01/03/2008
Effective Date:
02/07/2008
Make:
Pratt & Whitney Division
Model:
PW4164 | PW4168 | PW4168A
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Superseded AD: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Superseded By: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:
Automatic Zoom
Actual Size
Page Fit
Page Width
⁨50⁩%
⁨75⁩%
⁨100⁩%
⁨125⁩%
⁨150⁩%
⁨200⁩%
⁨300⁩%
⁨400⁩%
125%
of ⁨5⁩
1


[Federal Register: January 3, 2008 (Volume 73, Number 2)]


[Rules and Regulations]


[Page 394-395]


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


[DOCID:fr03ja08-2]


––––––––––––––––––––––––––––––––––


DEPARTMENT OF TRANSPORTATION


Federal Aviation Administration


14 CFR Part 39


[Docket No. FAA-2007-27230; Directorate Identifier 2007-NE-04-AD] Amendment 39-15322;


AD 2007-26-20]


RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney (PW) PW4164, PW4168, and PW4168A Turbofan


Engines


AGENCY:
 
Federal Aviation Administration (FAA), Department of Transportation (DOT).


ACTION:
 
Final rule.


––––––––––––––––––––––––––––––––––


SUMMARY:
 
The FAA is adopting a new airworthiness directive (AD) for PW PW4164, PW4168,


and PW4168A turbofan engines with certain low pressure turbine (LPT) stage 4 disks, part number


(P/N) 51N404, installed. This AD requires removing certain LPT stage 4 disks, listed by serial


number at the next piece-part exposure or within 7,500 cycles-since-new (CSN). This AD results


from a report of improperly manufactured LPT stage 4 disks. We are issuing this AD to prevent an


uncontained engine failure due to low-cycle fatigue (LCF), which could result in damage to the


airplane.


DATES:
 
This AD becomes effective February 7, 2008.


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:
 
V. Rose Len, Aerospace Engineer, Engine


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


Burlington, MA 01803; telephone (781) 238-7772; fax (781) 238-7199.


SUPPLEMENTARY INFORMATION:
 
The FAA proposed to amend 14 CFR part 39 with a


proposed AD. The proposed AD applies to PW PW4164, PW4168, and PW4168A. We published the


proposed AD in the Federal Register on May 21, 2007 (72 FR 28459). That action proposed to


require removing certain LPT stage 4 disks, P/N 51N404, listed by serial number in the proposed AD,


at the next piece-part exposure, or within 7,500 CSN, whichever occurs first.
2


Examining the AD Docket


You may examine the AD docket on the Internet at http://www.regulations.gov; 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 AD, the regulatory evaluation, any comments received, and


other information. The street address for the Docket Operations office (telephone (800) 647-5527) is


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


receipt.


Comments


We provided the public the opportunity to participate in the development of this AD. We have


considered the comment received.


Pratt & Whitney proposes that we not write an AD. Pratt & Whitney states that they performed


additional testing for low-cycle fatigue (LCF). They state the testing shows the disks with the 1-hour


heat treatment are equivalent to the disks treated with a 4-hour heat treatment. We do not agree. The


data that PW presents to us doesn't conclusively show the 1-hour heat-treat LCF capability is


equivalent to the 4-hour heat-treat disks. We didn't change the AD.


Conclusion


We have carefully reviewed the available data, including the comment received, and determined


that air safety and the public interest require adopting the AD as proposed.


Costs of Compliance


We estimate that this AD will affect 11 engines installed on airplanes of U.S. registry. We also


estimate that it will take about 250 work-hours per engine to perform the required action, if not done


at piece-part exposure, and that the average labor rate is $80 per work-hour. Required parts will cost


about $186,288 per engine. Based on these figures, we estimate the total cost of the AD to U.S.


operators to be $2,269,168.


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 this AD: