[4910-13-P)

DEPARTMENT OF TRANSPORTATION Federal Aviation Administration



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# 116~ (Docket No. FAA-2010-++++j Directorate Identifier 2010-NM-125-ADI

ACTION: Notice ofproposed rulemaking (NPRM). AGENCY: Federal Aviation Administration (FAA), Department ofTransportation Airworthiness Directives; The Boeing Company Model 747 Airplanes (DOT). RIN 2120-AA64

SUMMARY: The FAA proposes to supersede an existing airworthiness directive (AD) NlnALSlSlG 14 CFR Part 39

that applies to all Model 747 airplanes. The existing AD currently requires repetitive inspections to detect damage ofthe sleeving andwire bundles ofthe boost pumps ofthe s- 

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## wS numbers I and 4 main fuel tanks, and of the auxiliary tankjettison pwnps (if installed); replacement ofany damaged sleeving with new sleeving; and repair or replacement of 

# <t/27ho any damaged wires with new wires. For airplanes on which any burned wires are foundl OUTING SYMllOL the existing AD also requires an inspection to detect damage ofthe conduit, and IINITI~SlSIG 

### C-G-<-- replacement ofallYdamaged conduit with a serviceable conduit. This proposed AD I ATE Ji O1I(od would reduce the initial compliance time and repetitive inspection interval inthe existin OUl1NGSYMBOL

# o AD. This proposed AD results from fleet information indicating that the repetitive inspection interval inthe existing AD is too long because chafing of the sleeving continues to occur much earlier than expected between scheduled inspections. We are proposing this AD to detect and correct abrasion ofthe Teflon sleeving and "'lires inthe

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# .IiIITS bundles ofthe fuel boost pumps for the numbers 1and 4 main fuel tanks and ofthe 

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. 'w ,/ auxiliary tankjettison pumps (ifinstalled), wruch could result in electrical arcing betwe n I

## II/B OlmNG SYMIlC( the wires and aluminum conduit and consequent fire or explosion oftile fuel tarue[4910-13-P] I DEPARTMENT OF TRANSPORT AnON Federal Aviation Administration CIIIUlEI<CES OUTING $V>IIlOl 14CFR Part 39 (Docket No. FAA-2010-++++j Directorate Identifier 2010-I\TM-125-ADJ ·RIN 2120-AA64 IIDLOLSI~'G 

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NmALS/SlG Ainvortbiness Directives; The Boeing Company Model 747 Airplanes AGENCY: Federal Aviation Administration (FAA), Department ofTransportation

numbers 1and 4 main fuel tanks, and ofthe auxiliary tankjettison pumps (ifinstalled); inspections to detect damage ofthe sleeving and wire bundles ofthe boost pumps ofthe ACTION: Notice ofproposed rulemaking (NPRM). SUMMARY: The FAA pr,?poses to supersede an existing airworthiness directive (AD) ~ that applies to all Model 747 airplanes. The existing AD currently requires repetitive " (DOT).



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replacement ofany damaged sleeving with new sleeving;,and repair or replacement of 

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any damaged wires with new wires. For airplanes on which any bumed wires are found OUllNG SYMBO<,. the existing AD also requires an inspection to detect damage of the conduit, and NlTIAt..S!SlG replacement ofany damaged conduit with a serviceable conduit. This proposed AD

inspection interval inthe existing AD is too long because chafing ofthe sleeving AD. This proposed AD results from fleet information indicating that the repetitive would reduce the initial compliance time and repetitive inspection interval inthe existin I oun'lG SVMBO" I , 

# i",n.~"c (' continues to occur much earlier than expected between scheduled inspections. We are OlInNG SVMBOL proposing this AD to detect and correct abrasion ofthe Teilon sleeving and wires inthe I· mnAl.5lSIG bundles ofthe fuel boost pumps for the numbers I and 4 main fuel tanks and ofthe auxiliary tankjettison pumps (if installed), which could result in electrical arcing betwe n
~~~ the wires and aluminum conduit and consequent fire or explosion ofthe fuel tank.