[4910-13-P)

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

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

ACTION: Notice of proposed rulemaking (NPRM).

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

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 of the sleeving and wire bundles of the boost pumps of the s- A wll'L-J wS

numbers I and 4 main fuel tanks, and of the auxiliary tank jettison pwnps (if installed);

replacement of any 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 of the conduit, and IINITI~SlSIG

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replacement of allY damaged conduit with a serviceable conduit. This proposed AD I ATE

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would reduce the initial compliance time and repetitive inspection interval in the existin OUl1NGSYMBOL

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AD. This proposed AD results from fleet information indicating that the repetitive

inspection interval in the 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 of the Teflon sleeving and "'lires in the - L) .IiIITS

bundles of the fuel boost pumps for the numbers 1 and 4 main fuel tanks and of the ff .

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auxiliary tank jettison pumps (if installed), wruch could result in electrical arcing betwe n I II/B

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the wires and aluminum conduit and consequent fire or explosion of tile fuel tarue
[4910-13-P]

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DEPARTMENT OF TRANSPORT AnON

Federal Aviation Administration CIIIUlEI<CES

OUTING $V>IIlOl

14 CFR Part 39

(Docket No. FAA-2010-++++j Directorate Identifier 2010-I\TM-125-ADJ

·RIN 2120-AA64

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Ainvortbiness Directives; The Boeing Company Model 747 Airplanes

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

numbers 1 and 4 main fuel tanks, and of the auxiliary tank jettison pumps (if installed);

inspections to detect damage of the sleeving and wire bundles of the boost pumps of the

ACTION: Notice of proposed 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). - , ,

replacement of any damaged sleeving with new sleeving;,and repair or replacement of ."

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 of any damaged conduit with a serviceable conduit. This proposed AD

inspection interval in the existing AD is too long because chafing of the sleeving

AD. This proposed AD results from fleet information indicating that the repetitive

would reduce the initial compliance time and repetitive inspection interval in the 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 of the Teilon sleeving and wires in the I·

mnAl.5lSIG

bundles of the fuel boost pumps for the numbers I and 4 main fuel tanks and of the

auxiliary tank jettison pumps (if installed), which could result in electrical arcing betwe n

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the wires and aluminum conduit and consequent fire or explosion of the fuel tank.