(4910-I3-P)

DEPARTMENT OF TRANSPORT ATlON

Federal Aviation Administration

14 CFR Part 39

2-010- D03S-

(Docket No. FAA-~-l I I I I; Directorate Identifier 2009-NM-066-AD)

RlN 2120-AA64

Ainvorthiness Directives; Boeing Model 747-400, 747-400D, and 747-400F Series

Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulcmaking (NPRM).

/305

SUMMARY: We propose to adopt a new ainvorthiness directive (AD) for Boeing Mod flTIAL G

O~'E

proposed AD results from fuel system reviews conducted by the manufacturer. We are

proposing this AD to prevent an electrical hot short from -asource outside the FQIS to th O<JTl~G~t16OL01

densitometer wiring from causing failure of the FQIS densi~ometer resistors, which coul t!:,~-.J6

result in an ignition source inside the center or horizontal stabilizer fuel tanks. An ~vJ

747-400, 747-400D, and 747-400F series airplanes. This proposed AD would require

installing a hot short protector (lISP) for the fuel quantity indicating system (FQIS) oft

center fuel tank, and for certain airplanes, the horizontal stabilizer fuel tank. This

ignition source, in combination with flammable fuel vapors, could result in a fuel tank

explosion and consequent loss of the airplane.

DATES: We must receive comments on this proposed AD by [insert date 45 days after

date of publication in the FEDERAL REGISTER].

ADDRESSES: You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the

instructions for submitting comments. "

• Fax: 202-493-2251.

.)-. {O
(4910-I3-P]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

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RIN 2120-AA64

Airworthiness Directives; Boeing Model 747-400, 747-400D, and 747-400F Series

Airplanes

AGENCY: Federal Avialion Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

result in an ignition source inside the center or horizontal stabilizer fuel tanks. An

ignition source, in combination with flammable fuel vapors, could result in a fuel tank

proposed AD results from fuel system reviews conducted, by the manufacturer. We are

proposing this AD to prevent an electrical hot short from a source outside the .FQIS to t

densitometer wiring from causing failure of the FQIS densitometer resistors, which coul

747-400, 747-400D, and 747-400F series airplanes. This proposed AD would require

installing a hot short protector (HSP) for the fuel quantity indicating system (FQIS) oft

center fuel tank, and for certain airplanes, the horizontal stabilizer fuel tank. This

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for Boeing Mod r <: G

14 CFR Part 39

IDocket No. FAA-2009-1 I r I I; Directorate Identifier 2009-NM-866-AD]

explosion and consequent loss of the airplane.

I<mALSISIG

DATES: We mllst receive comments on this proposed AD by [insert date 45 days after

m.

dale of publication in the FEDERAL REGISTER].

ADDRESSES: You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://W\vw.regulations.gov. Follow the

,

instructions for submitting comments. ~

• Fax: 202493-2251.

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