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ACTION: Notice of proposed rulemaking (NPRM).

Series Airplanes

AilWorthincss Directives; The Boeing Company Model 37-200, -300, -400, and -500

RlN 2120-AA64

AGENCY: Federal Aviation Administration (FAA), DOT.

D431

[Docket No. FAA-2010-1 I I I I; Directorate Identifier 2009-NM-130-AD]

SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Mode

737-200, -300, -400, and -500 series airplanes. This propjsed AD would require

repetitive inspections for cracking of certain fuselage fTJes and stub beams, and

corrective actions if necessary. This proposed AD also prtvides for an optional repair, ~:,~".,,~,

which would terminate the repetitive inspections. For airpianes on which a certain repair

is done, this proposed AD would also require repetitive ilpections for cracking of

certain fuselage frames and stub beams, and corrective actons if necessary. This

proposed AD results from reports of tile detection offatigle cracks at certain frame RlM"NG5\'MrlOl.

sections, in addition to stub beam cracking, caused by hi~ flight cycle stresses from bot 'NIlIAI.SiSICi

pressurization and maneuver loads. We are proposing thi, AD to detect and correct =:'~"'MOO'

fatigue cracking of certain fuselage frames and stub beams and possible severed frames,

which could result in reduced structural integrity of the frLes. This reduced structural "m,,'SSIG

integrity can increase loading in the fuselage skin, which r" accelerate skin crack

growth and could result in rapid decompression of the fuSrlage.

DATES: We must receive comments on this proposed AID by [INSERT DATE 45

DAYS AFTER DATE OF PUBLICATION IN THE FEDbRAL REGISTER].

14 CFR Part 39

Federal Aviation Administration

DEPARTMENT OF TRANSPORTATION

ADDRESSES: You may send comments by any of the fo lowing methods:
(4910-13-P]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration a"(UR~ENCES

ROUnNG SYMBOl14 CFR Part 39

(Docket No. FAA-2009-+++++; Directorate Identifier 009-NM-130-AD]

RIN 2120-AA64

Airworthiness Directivesj Boeing Model 737-~OO~-300, -400, and -500 Series

Airplanes

AGENCY: Federal Aviation Administration (FAA), DO

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is done, this proposed would also require repetitive inspe tions for cracking of certain

result in reduced structural integrity of the frames. This re uced structural inteb'Titycan

ACTION: Notice of proposed rulemaking (NPRM).

Mff-ili;Jj

INrT1AtS!:>'G

A Pol, I t¥""

Boeing Model 737-200, -300, -400, and -500 series airpl es. This proposed AD would DATE

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require repetitive inspections for cracking of certain fusel~ge frames and ShIb beams, an oulmQ $yml>ol

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cor~ectiveactions ~fneceSSary.~~iSp.ropose~AD also ~r~vides for a~ optional ~epair,. :?~ISIG . ...

whIch would termmate the repetItlVe mspectlOns. For alrp~anes on which a certam repaIr DAT~

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fuselage frames and stub beams, and corrective actions if ecessary. This proposed AD

SUMMARY: We propose t~ adopt a new airworthiness irective (AD) for certain

results from reports of the detection of fatigue cracks at c ,rtain frame sections, in

addition to stub beam cracking, caused by high flight cYcib stresses from both

pressurization and maneuver load. We are proposing this "[~ to prevent fatigue cracking ..-J.ODS r "1T~~r!

of certain fuselage frames and stub beams and possible sewered frames, which could ,/. ~~

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increase loading in the fuselage skin, which will accelerat skin crack groVv1hand result

in rapid decompression afthe fuselage.

DATES: We must receive comments on;this proposed A by [insert date 45 days after

dale of publication in the FEDERAL REGISTER].

OUTlNG SYMBOL

ADDRESSES: You may send comments by any of the fa lowing methods:

NmALS/SIG
14910-13-P]

DEPARTMENT OF TRANSPORT AnON

Federal Aviation Administration

14 CFR Part 39 fhJm~l<\

1'I1T1AI.SISIG

rDocket No. FAA-2009-1 I I I I; Directorate Identifier 2i009-NM-130-AD]

RIN 2120-AA64

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Ainvorthiness Directives; Boeing Model 737-2.00, -300'J1400' and -SOD Series

Airplanes

AGENCY: Federal Aviation Administration (FAA), DO"

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: We propose t? adopt a new airworthiness di ective (AD) for certain

Boeing Model 737-200, -300, -400, and -500 series airpla es. This proposed AD would

require repetitive inspections for cracking of certain fusda c frames and stub beams, an

corrective actions if necessary. This proposed AD also prorides for an optional repair, l~:~:Wc,

which would terminate the repetitive inspections. For airplanes on which a certain repair """~ l;'-

I

is done, this proposed would also require repetitive inspectrons for cracking of certain ,sf-AfO

fuselage frames and stub beams, and corrective actions if~ecessary. This proposed AD NlT\ALSlSIG

I J {>DI-[S results from reports of the detection of fatigue cracks at CCfin frame sections, in

t{/II (67 addition to stub beam cracking, 'caused by high flight cycle stresses from both

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pressuri7..ation and maneuver load. We are proposing this f\!D to prevent fatigue cracking .-t{():> I NmlUS/S1G

of certain fuselage frames and stub beams and possible severed frames, which could

result in reduced structural integrity of the frames. This redlced structural integrity can

increase loading in the fuselage skin, which will accelerate skin crack growth and result

in rapid decompression of the fuselage.

DATES: We must receive comments on',this proposed AD by [insert date 45 days after

date of publication in the FEDERAL REGISTER].

ADDRESSES: You may send comments by any of the following methods: