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14CFR Part 39 DEPARTMENT OF TRANSPORTATION Federal Aviation Administration



# oqSLf [Docket No. FAA-2010-++++; Directorate Identifier 2010-NM-078-AD] RlN 2120-AA64 Airworthiness Directives; Hawker Beechcraft Corporation (Type Certificate Previous Held by 

### Raytheon Aircraft Company; Beech Aircraft Corporation) Model400A and 400T Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice ofproposed rulemaking (NPRM). SUMMARY: We propose to adopt anew airworthiness directive (AD) for certain Mo 

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### 400A. and 400T airplanes. This proposed AD would require adetailed inspection for l<11'AlS'SlG 

### proper sealant ofthe left andright pylon firewall structures, and corrective actions 

### if necessary. This proposed AD results from reports ofmissing sealant on the left and rig1 Ol)TING .\I"Mllol. t 

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## " • Fax: 202-493-2251. instructions forsubmitting comments. • Federal eRulemaking Portal: Go to http://v.... \vw.regulations.gov. Follow the ADDRESSES: You may send comments by allYofthe following methods: DATES: We must receive comments on lhis proposed AD by [INSERT DATE 45 fuselage, and asubsequent uncontrolled fire inthe aft fuselage. result inflames penetrating the seams in the firewall between the engine and the aft on the left and right pylon firewall structures, which, inthe event ofan engine fire, cou

DAYS AFTER DATE OFPUBLICATION INTHE FEDERAL REGISTER]. I INIllAU;ISIG 

### pylon firewall structures. We areproposing this AD todetect and correct missing sealaJ~FU1"';::;5"r"""C 

### p6Wp JJ RIN 2120-AA64 IDocket No. FAA-2010-++++j Directorate Identifier 20IO-NM-078-ADI 14eFR 

### Part 39 Fedcl"al Aviation Administration

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Held by Raytheon Aircraft Company; Beech Aircraft Corporation) Model 400A and 400'1'Airplanes AGENCY: Federal Aviation Adll1inistnHion (FAA), DOT. 

### ACTION: Notice ofproposed ruJemaking (NPRM). SUMMARY: We propose to adopt anew airworthiness directive (AD) for certain Mo •..•. ,"l.'ij~"'''''

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### qt'"A~'EWG~ 400A, and 4001' airplanes. This proposed AD would require adetailed inspection for 

## I proper sealant ofthe left and right pylon firewall structures, and correclive actions if 

# "~%r:;l ncx:cssary. This proposed AD results from reports of missing sealant on the left and flgi t~ S- 

# to I pylon firewall structures. We are proposing this AD 10 detect and correct missing scala all the left and right pylon firewall structures, which, inlhe event of an engine fire, Call result in flames penetrating the seams in the firewall between the engine and the aft fuselage, and a subsequent uncontrolled fire in the aft fuselage. DATES: We must receive comments on this proposed AD by (INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION INTHE FEDERAL REGISTER]. ADDRESSES: You may send comments 

### by any ofthe following melhods:
• Federal eRulemaking Porlal: Go 10http://w,V\v.regulations.!!ov. Follow the inSlructions for $ubl11iningcomments . • Fax: 202-493~2251.

FAA Form 1360-14.1 (6-89) OFFICIALFILECOPY