[4910-13-P]

DEPARTMENT OF TRANSPORT AnON

14 CFR Part 39

Federal Aviation Administration

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

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inspections for cracking in the skin splice plate at the aft corners of the nose wheel well;

RlN 2120-AA64

and related investigative and corrective actions if necessary. This proposed AD would

Airworthiness Directives; The Boeing ComPjY Model 747 Airplanes

AGENCY: Federal Aviation AdmillistratiOn(JAA), DOT.

ACTION: Notice of proposed 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~ m the 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 for steel cross-shaped doublers on

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the larger aluminum doublers; and cOlTective artiOD if necessary. This proposed AD

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would also require repetitive surface high freqrncy eddy current (HFEC) inspections 0 'I"TIAlSiSIG

a ce11ainbulkhead outer chord, skin splice PlaT and outer chord radius filler for ~""_",,,, _

cracking; repetitive detailed inspections for cracking of the bulkhead frame web and bo

I NOurlNG 5YM80l skin; and corrective actions If necessary. This flroposed AD would provide for optional

.. . C . ... l TI . dAD I f ~"-H-O~-·-"o--- tennmatlOg action ior certam repetltlve lJlSpcctlOllS. 11Spropose resu ts Tom

I kwom-- repOlis of cracking ofthe fuselage skin and adjacent internal skin splice plate at the left

and right nose wheel well aft comers, and the +ter chord of the body station (BS) 400 "'~,~"""',.

bulkhead. We are proposing this AD to detect and correct cracking of the fuselage skin '~"IM.SISJG

splice plate, which, together with cracking of tile bulkhead outer chord. could result in L"_'"

large skin cracks and subsequent in-flight rapi decompression of the airplane.
[4910·13·P)

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-++++; Directorate Identifier 201O-NM-012-AD)

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RlN 2120-AA64

in the body skin around the aft comers of the nose wheel well; for certain airplanes,

Airworthiness Directives; The Boell1g CompTY Model 747 AIrplanes RO~~~"'B:l ZJi!lJL

AGENCY: Federal Aviation Admmistration (flAA), DOT. d INITIAl..SiSIG >

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ACTION: NOlice of proposed rulemaking (NPRM). <;:/ '''".., I

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

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747 airplanes. This proposed AD would require doing repetitive inspections for crackin , m.o.LSlSIG

repetitive inspections for cracking in the skin splice plate at the aft comers of the nose

wheel well; and modification of the skin and splice plate doublers if necessary. This

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proposed AD would also require repetitive post-modification inspections for cracking a

corrective action if necessary. This proposed AID would also require doing repetitive

surface high frequency eddy current (HFEC) in~pection of the bulkhead outer chord for

cracking, repetitive detailed inspections for cra1king of the hulkhead frame web and bo

skin, and corrective actions if necessary. This proposed AD results from reports of

cracking of the fuselage skin and adjacent inte1al skin splice plate at the left and right

nose wheel well aft comers, and the outer chord of the body station (BS) 400 bulkhead.

In addition, cracks were found in the adjacent BS 400 bulkhead outer chord. We are

proposing this AD to detect and correct cracking of the fuselage skin or splice plate,

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which together with cracking of the bulkhead outer chord could result in large skin crac s

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and subsequent in-flight rapid decompression of the airplane.

DATES: We must receive comments on this prtPosed AD by [INSERT DATE 45

DAYS AFTER DATE OF PUBLICATION IN ifl-lE FEDERAL REGISTER].

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(4910-13-P]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration O"(URllHKES

OUTING S'rMBOL

14 CFR Part 39

(Docket No. FAA-20JO-++++; Directorate Identifier 2010-NM-012-ADj

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in the body skin around the aft comers of the nose wheel well; for certain airplanes,

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repetitive inspections for cracking in the skin splice plate at the aft comers of the nose

I

wheel well; and modification of the skin and splice plate doublers if necessary. This

proposed AD would also require repetitive post-modification inspections for cracking

corrective action if necessary. This proposed AD would also require doing repetitive

surface high frequency eddy current (HFEC) inspecl'ion of the bulkhead outer chord for

cracking, repetitive detailed inspections for CraC1ingof the bulkhead frame web and bo

skin, and corrective actions if necessary. This proposed AD results [Tom reports of

cracking of the fuselage skin and adjacent internal skin splice plate at the left and right i).... rY~1V~5

Ainvorthiness Directives; The Boei.ng Company Model 747 Airplanes OIJTl'IGSYMBOl ;(.1

I 11,e,y)- 21LJ1JL

AGENCY: Federal Aviation Administration (F~A), DOT. d INm~L$!SIG;

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ACTION: Notice of proposed rulemaking (NPRM). >/~J;'" ~-2(-10

SUMMARY: We propose to adopt a new airworthiness directive (AD) for ccrtai;.{Mod 'lG5Y>llIOtt'l1Jm b

747 airplanes. This proposed AD would require doing repetitive inspections for crackin ' mALSiSlG . If

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nose wheel well aft corners, and the outer chord of the body station (8S) 400 bulkhead.

In addition, cracks were found in the adjacent BS 400 bulkhead outer chord. We are

proposing this AD to detect and correct cracking of the fuselage skin or splice plate,

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which together with cracking of the bulkhead outer chord could result in large skin crac s

,

and subsequent in-flight rapid decompression of the airplane.

DATES: We must receive comments on this proposed AD by [fNSERT DATE 45 O'fllHG STHilOL

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER).