[4910-13-P]

DEPARTMENT OF TRANSPORT AnON
14CFR Part 39 Federal Aviation Administration



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# 14 [Docket No. FAA-10IO-++++; Directorate Identifier 2010-NM.-012-AD) 

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and related investigative and corrective actions ifnecessary. This proposed AD would Airworthiness Directives; The Boeing ComPjY Model 747 Airplanes AGENCY: Federal Aviation AdmillistratiOn(JAA), DOT. ACTION: Notice ofproposed rulemaking 

### (]NRRM). SUMMARY: We propose to adopt a new a" ilthiness directive (AD) for aU ModeJ 7 ail~lanes. This proposed AD "vQuldrequire rePlctitive inspe~tio~s for craCkin~ mthe bo Sklll around the aft cOrilers of the nose wheel \,"ell; for certam airplanes, repetitive

also require repetitive post-modification inspeTons for cracking in the body skin and th 'N,'rLAl";£IG skin splice plate; for certain airplanes, an inspection forsteel cross-shaped doublers on I "ATI, the larger aluminum doublers; and cOlTectiveartiODifnecessary. This proposed AD keo""o""''''(;'''''',"''o'''c
- would also require repetitive surface high freqrncy eddy current (HFEC) inspections 0 'I"TIAlSiSIG ace11ainbulkhead outer chord, skin splice PlaT and outer chord radius filler for ~""_",,,,

_ cracking; repetitive detailed inspections for cracking ofthe bulkhead frame web and bo I NOurlNG 5YM80l skin; and corrective actions Ifnecessary. This flroposed AD would provide foroptional

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# I kwom-- repOlis ofcracking ofthe fuselage skin and adjacent internal skin splice plate atthe left and right nose wheel well aftcomers, and the +ter chord ofthe body station (BS) 400 "'~,~"""',. bulkhead. We areproposing this AD to detect and correct cracking ofthe fuselage skin '~"IM.SISJG splice plate, which, together with cracking oftilebulkhead outer chord. could result in L"_'" large skin cracks and subsequent in-flight rapi decompression ofthe airplane.[4910·13·P)

DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14CFR Part 39 [Docket No. FAA-2010-++++; Directorate Identifier 201O-NM-012-AD) 

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inthe body skin around the aft comers ofthe nose wheel well; for certain airplanes, Airworthiness Directives; The Boell1g CompTY Model 747 AIrplanes RO~~~"'B:l 

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## 1. . ACTION: NOliceofproposed rulemaking (NPRM). 

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# 0 SUMMARY: We propose to adopt anew airw0rthiness directive (AD) for certaiJMod lITINGS'/>l!IOL 

## I\iJm ~ 747 airplanes. This proposed AD would require doing repetitive inspections for crackin , m.o.LSlSIG repetitive inspections for cracking in the skin splice plate atthe aft comers ofthe nose wheel well; and modification ofthe skin and splice plate doublers ifnecessary. This • proposed AD would also require repetitive post-modification inspections for cracking a corrective action ifnecessary. This proposed AID would also require doing repetitive surface high frequency eddy current (HFEC) in~pection ofthe bulkhead outer chord for cracking, repetitive detailed inspections for cra1king ofthe hulkhead frame web and bo skin, and corrective actions ifnecessary. This proposed AD results from reports of cracking ofthe fuselage skin and adjacent inte1al skin splice plate at the left and right nose wheel well aft comers, and the outer chord ofthe body station (BS) 400 bulkhead. Inaddition, cracks were found in the adjacent BS 400 bulkhead outer chord. We are proposing this AD to detect and correct cracking ofthe fuselage skin or splice plate, H!11AlSIS1G which together with cracking ofthe bulkhead outer chord could result in large skin crac s , and subsequent in-flight rapid decompression ofthe airplane. DATES: We must receive comments on this prtPosed AD by [INSERT DATE 45 DAYS AFTER DATE OF PUBLICATION IN ifl-lEFEDERAL REGISTER]. 

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DEPARTMENT OF TRANSPORTATION Federal Aviation Administration O"(URllHKES OUTING S'rMBOL 14CFR Part 39 (Docket No. FAA-20JO-++++; Directorate Identifier 2010-NM-012-ADj 

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inthe body skin around the aftcomers ofthe nose wheel well; for certain airplanes, I . repetitive inspections for cracking in the skin splice plate atthe aft comers ofthe nose I wheel well; and modification ofthe skin and splice plate doublers ifnecessary. This proposed AD would also require repetitive post-modification inspections for cracking corrective action ifnecessary. This proposed AD would also require doing repetitive surface high frequency eddy current (HFEC) inspecl'ion ofthe bulkhead outer chord for cracking, repetitive detailed inspections for CraC1ingofthe bulkhead frame web and bo skin, and corrective actions ifnecessary. This proposed AD results [Tomreports of cracking ofthe fuselage skin and adjacent internal skin splice plate atthe left and right i)....rY~ 

# 1V~5 Ainvorthiness Directives; The Boei.ngCompany Model 747 Airplanes OIJTl'IGSYMBOl ;(.1 I 11,e,y)-21LJ1JL AGENCY: Federal Aviation Administration (F~A), DOT. d INm~L$!SIG; 

## I r,~ 1. ' ACTION: Notice ofproposed rulemaking (NPRM). 

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# -10 SUMMARY: We propose to adopt anew airworthiness directive (AD) for ccrtai;.{Mod 'lG5Y>llIOt

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## b 747 airplanes. This proposed AD would require doing repetitive inspections forcrackin ' mALSiSlG . 

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N'TIMSlS'G nose wheel well aftcorners, and the outer chord ofthebody station (8S) 400 bulkhead. Inaddition, cracks were found inthe adjacent BS 400 bulkhead outer chord. We are proposing this AD to detect and correct cracking ofthe fuselage skin or splice plate, OUTlNGSYl<lWl "!nAl${SrG which together with cracking ofthe bulkhead outer chord could result in large skin crac s , and subsequent in-flight rapid decompression ofthe airplane. DATES: We must receive comments on this proposed AD by [fNSERT DATE 45 O'fllHG STHilOL DAYS AFTER DATE OF PUBLICATION INTHE FEDERAL REGISTER).