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DEPARTMENT OF TRANSPORTATION Federal Aviation Administration O~CUI\I\E'lCES 0I/TlN(; S'iM60L



## I~S- {I-IiNITIIlLS/SIG 

# 03'5'3 [Docket No. FAA-2010-++++; Directorate Identifier 2009-NM-214-ADJ
Airworthiness Directives; The Boeing Company Model 747-100, 747-100B, '. '. I 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP 

## 1.li 14 CFR Part 39

: RIN 2120-AA64

Series Airplanes 

### 2-2 -\

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GSf ilOl If'llTl S/SIG

~. instructions for submitting comments. DATES: We must receive corrunents on this proposed AIDby [INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION INTHE FEDF.RAL REGISTER]. ADDRESSES: You may send comments by any ofthe following methods:

• Federal eRulemaking Portal: Go to http://www.lgulations.gov. Follow the AGENCY: Federal Aviation Administration (FAA), DOl' ACTION: Notice ofproposed rulemaking (NPRM). 

## ,,~ SUMMARY: We propose to adopt anew airworthiness drrective (AD) for certain Mod I 5 \U 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200G:,747-200F,747-300, 747-40

# ;1J\£6 747SR, and 747SP series airplanes. This proposed AD wolld require repetitive detailed Nmi\l.Sf51G inspections ofcertain overwing intercostal webs, and rel'led investigative and correctiv 

### A{lfl actions ifnecessary. This proposed AD results from reports'.of cracks in overwing ,NG SYMBOL intercostal webs. We are proposing this AD to detect and 

### Lrrect such cracking, which could grow and result in a severed,intercostal. Ifan intercbstal is severed, cracks could develop inthe adjacent frame structure and skin, reSUltinJin arapid loss ofcabin pressure.

• Fax: 202-493-2251. NmALSfS1GDEPARTMENT OF TRANSPORT ATION

Federal Aviation Administration •.OO/C<;RI{E''!CI:'S DUTING sYMllOl 14CFR Part 39 [Docket No. FAA-201O-++++; Directorate Identifier 2009-NM-2I4-AD] RIN 2120-AA64 Ain\'orthiness Directives; The Boeing Company Model 747-100, 747-100B, 

## /.;cs· (HI747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP 

## 1.l; Series Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. 

### .2-2

# -10
ACTION: Notice ofproposed rulemaking (NPRM). SUMMARY: We propose ~oadopt anew airv.rorthiness d~rective (AD) for certain Mod

# rn: I I 5 \0



# ,- 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-40 

### '5Qii'fq 747SR, and 747SP series airplanes. This proposed AD would require repetitive detailed inspections ofcertain overwing intercostal webs, and relatld investigative and correctiv 

# I actions 

### ifnecessary. This proposed AD results from reports ofcracks in overwing intercostal webs. We are proposing this AD to detect and correct such cracking, which could grow and result in a severed intercostal. Ifan intercoltal is severed, cracks could develop inthe adjacent frame structure and skin, resulting in a rapid loss ofcabin pressure. DATES: We must receive comments on this proposed AD by [fNSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER]. ADDRESSES: You may send comments by any ofthe fOllOWingmethods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov.Fo(low the

~ instructions for submitting comments .
• Fax: 202-493-2251. ••mALSISIG

••mALSISIG