AD 2004-24-03

AD Final Rules - 042403.pdf
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AD Number:
2004-24-03
Document Type:
AD Final Rules
Docket Number:
2003-NE-61-AD
Subject Heading:
Airworthiness Directives; Hamilton Sundstrand Power Systems T-62T Series Auxiliary Power Units (APUs)
Subject:
Internal o-ring seal
Status:
Current
Citation:
Federal Register: November 26, 2004 (Volume 69, Number 227)
Citation Publish Date:
11/26/2004
Effective Date:
01/03/2005
Make:
Bombardier Inc. | Embraer S.A. | Hamilton Sundstrand Power Systems
Model:
DHC-8-101 | DHC-8-102 | DHC-8-103 | DHC-8-106 | DHC-8-201 | DHC-8-202 | DHC-8-301 | DHC-8-311 ...Show more
Product Type:
Appliance
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Superseded AD: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Superseded By: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: November 26, 2004 (Volume 69, Number 227)]


[Rules and Regulations]


[Page 68767-68769]


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


[DOCID:fr26no04-6]


–––––––––––––––––––––––––––––––––––


DEPARTMENT OF TRANSPORTATION


Federal Aviation Administration


14 CFR Part 39


[Docket No. 2003-NE-61-AD; Amendment 39-13879 AD 2004-24-03]


RIN 2120-AA64


Airworthiness Directives; Hamilton Sundstrand Power Systems T-62T Series Auxiliary Power


Units (APUs)


AGENCY:
 
Federal Aviation Administration (FAA), DOT.


ACTION:
 
Final rule.


–––––––––––––––––––––––––––––––––––


SUMMARY:
 
The FAA is adopting a new airworthiness directive (AD) for Hamilton Sundstrand


Power Systems Models T-62T-46C12 and T-62T-40C14 (APS 500R) APUs with fuel filter housing


assembly, part number (P/N) 4951627, 4951960, or 4952039, installed. This AD requires installation


of a bracket to prevent a failed bypass button from protruding beyond the internal o-ring seal. This


AD results from reports of leaks caused by cracked bypass buttons that protruded beyond the o-ring


seal. We are issuing this AD to prevent a fire or explosion caused by a fuel leak from a failed bypass


button on the fuel filter housing.


DATES:
 
This AD becomes effective January 3, 2005. The Director of the Federal Register approved


the incorporation by reference of certain publications listed in the regulations as of January 3, 2005.


ADDRESSES:
 
You can get the service information identified in this AD from Hamilton Sundstrand


Technical Publications Department, P.O. Box 7002, Rockford, IL 61125-7002, U.S.A.


You may examine the AD docket at the FAA, New England Region, Office of the Regional


Counsel, 12 New England Executive Park, Burlington, MA. You may examine the service


information, at the FAA, New England Region, Office of the Regional Counsel, 12 New England


Executive Park, Burlington, MA; or 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/code_of_federal_regulations/ibr_locations.html
.


FOR FURTHER INFORMATION CONTACT:
 
Roger Pesuit, Aerospace Engineer, Los Angeles


Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd.,


Lakewood, CA 90712-4137; telephone (562) 627-5251, fax (562) 627-5210.
2


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


proposed airworthiness directive (AD). The proposed AD applies to Hamilton Sundstrand Power


Systems Models T-62T-46C12 and T-62T-40C14 (APS 500R) APUs with fuel filter housing


assembly, P/N 4951627, 4951960, or 4952039 installed. We published the proposed AD in the


Federal Register on May 7, 2004 (69 FR 25525). That action proposed to require installation of a


bracket to prevent a failed bypass button from protruding beyond the internal o-ring seal.


Examining the AD Docket


You may examine the AD Docket (including any comments and service information), by


appointment, between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. See


ADDRESSES for the location.


Comments


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


considered the comments received.


Request To Add Alert Service Bulletin Reference


Two commenters request that for APUs Model T-62T-40C14 (APS 500R), we add EMBRAER


Alert Service Bulletin (ASB) No. 145-49-A027, dated January 6, 2004, as another means of


complying with the AD. We do not agree. That ASB does not contain instructions for installing the


bracket, but only instructs the operator to use Hamilton Sundstrand ASB No. ASB-4504112-49-22,


for installing the bracket. Because of this, we have not incorporated by reference that ASB.


Request To Reference the Latest ASB Revision


One commenter requests that we reference the latest revision of Hamilton Sundstrand ASB No.


ASB-4504112-49-22, which is Revision 1, dated January 5, 2004. The commenter states that the


original ASB specified a gap dimension of 0.32 inch-to-0.65 inch, which is incorrect and


unachievable. ASB Revision 1 corrects the gap dimension to the proper value of 0.50 inch, plus or


minus 0.015 inch. Also, ASB Revision 1 increases the recommended compliance threshold from


within 400 hours time-in-service (TIS) to within 500 hours TIS.


We agree that the latest ASB Revision should be referenced, which is Revision 2, dated October


4, 2004. The 500 hours TIS threshold is consistent with EMBRAER ASB No. 145-49-A027, dated


January 6, 2004. ASB Revision 2 requires, as does this AD, that brackets installed using Hamilton


Sundstrand ASB No. ASB-4504112-49-22, Original issue, be inspected one time for proper gap and


adjusted if necessary. ASB Revision 2 also introduces as an alternative, the installation of a different


part number fuel filter assembly for APU Model T-62-T-40C14, that is designed to prevent bypass


button failure. We have added that alternative as optional terminating action for APU Model T-62-T-


40C14.


We are allowing previous credit for brackets installed using Hamilton Sundstrand ASB No.


ASB-4504112-49-22, Original, dated December 2, 2003, or Revision 1, dated January 5, 2004, before


the effective date of this AD. We have incorporated the changes described previously in this AD.


Conclusion


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


that air safety and the public interest require adopting the AD with the changes described previously.