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DEPARTMENT OF TRANSPORTATION Federal Aviation Administ.-atioD 14CFR Part 39 

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_()O'-f(P IDocketNo. FAA-~+++++; Directorate Identifier 2009-NM-086-AD) R1N 212o-AA64 Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, and -800 Series Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice ofproposed rulemaking (NPRM). SUMMARY: Wepropose to adopt anew airworthiness directive (AD) forcertain Boeing Model 737-300, -400, -500, -600, -700, and -800 series airplanes. This proposed AD would require inspecting to verify thepart number ofthe low-pressure flex-hoses ofthe crew oxygen system installed under the oxygen mask stowage boxes located within the flight deck, and replacing with anew non-conductive Jow-pressure flex-hose ofthe crew oxygen system ifnecessary. This proposed AD results from reports oflow-pressure flex-hoses ofthe crew oxygen system that burned through due to inadvertent electrical current from a short circuit in the audio select panel. We are proposing this AD toprevent inadvertent electrical current which can cause the low-pressure flex-hoses ofthe crew oxygen system to melt or bum, causing oxygen system leakage and smoke orfire. DATES: We must receive comments on this proposed AD by [insert date 45 days after date ofpublicatiou in the FEDERAL REGISTER]. ADDRESSES: You may send comments by any ofthe following methods:

9 Federal eRulcmaking Portal: Go to http://www.regulations.eo\'. Follow the instructions for submitting comments.

• Fax: 202-493-2251. 

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# '".1 Boeing Model 737-300, -400, -500, -600, -700, and -800 series airplanes. This proposed DATE/ / '°(/(6 Y AD would require inspecting to verify the part number ofthe low-pressure flex-hoses 0 "'I"'l SymIl<II SUMMARY: We propose to adopt anew ainvorthincss directive (AD) for cert~in AGENCY: Federal Aviation Administration (FAA), DOT ACTION: Notice ofproposed rulemaking (J\TPRM). RlN 2120-AA64 Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, and -800 Series Airplanes

, f the crew oxygen system installed under the oxygen mask stowage boxes located within the flight deck.,and replacing with anew non-conductive low-pressure flex-hose ofthe crew oxygen system 

### ifnecessary. Tills proposed AD results from reports oflow-pres sur flex-hoses ofthe crew oxygen system that burned through due to inadvertent electrical current from a short circuit inthe audio select panel. We are proposing this AD to preve inadvertent electrical current which can cause the low-pressure flex-hoses ofthe crew oxygen system to melt or bum, causing oxygen system leakage and smoke orftre. DATES: We must receive comments on this proposed AD by [insert date 45 days after /IHlAlSlSIG date ofpublication inthe FEDERAL REGISTER]. ADDRESSES: You may send comments by any ofthe following methods: NmALSlSIG

ItFederal eRulemaking Portal: Go to http://www.regulations.gov.Foliowthe ) instructions for submitting comments. f, OlmNG sYMlI'X • Fax: 202-493-2251. N!TlAL5/SIG(49iO-I3-P]

DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14CFR Part 39 

### A1Jm-1i . tlmAI.S/SIG (Docket No. FAA-2009-1 I I I ,; Directorate Identifier 2009-NM--086-AD) RIN 2120-AA64 Ainvorthiness Directives; Boeing Model 737-300, -400, -500. -600, ~700.and -800 AGENCY: Federal Aviation Administration (FAA), DOT. Series Airplanes ACTION: Nolice ofproposed rulemaking (NPRM). 

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# .c,_ Boeing Model 737-300, -400, -500, -600, -700, and -800 series airplanes. This proposed 

## ';"i/ ,0(1(0 '1 AD would require inspecting to verify the part number ofthe low-pressure flex-hoses 0 Q"'~QSl"""'" SUMMARY: We propose to adopt anew airworthiness directive (AD) forcertain

the crew oxygen system installed under the oxygen mask stowage boxes located within the flight deck, and replacing with anew non-conductive low-pressure flex-hose ofthe crew oxygen system ifnecessary. This proposed AD results from reports oflow-pres sur flex-hoses ofthe crew oxygen system that burned through due to inadvertent electrical current from a short circuit inthe audio select panel. We are proposing this AD to preve inadvertent electrical current which can cause the low~pressure f1ex~hosesofthe crew OunNG"''''5Ol.

ovntlG SY"'BO oxygen system to melt orbum, causing oxygen system leakage and smoke orfire. DATES: We must receive comments on this proposed AD by [insert date 45 days after 

# .~ date ofpubJieation in the FEDERAL REGISTER]. ADDRESSES: You may send comments by any ofthe following methods: ounN'G SYHllOl
NmAl5tSIG eFederal eRulemaking Portal: Go to hnp:l/www.regulations.gov. Follow the instructions for submitting comments. ''-

• fax: 202-493-225 L limAl.SlSlG