This sheet transmitsREVISION 3datedNovember 30, 1989 of Service Bulletin 727-53A0124, "FUSELAGE

-MAINWHEEL WELL PRESSURE FLOOR INSPECTION,MODIFICATIONAND REPAIR". NOTE: This revisionconstitutesa complete reissue. SUMMARY This revision is issued to recommend the modification per this service bulletin for incorporation on aging 727 airplanes. Also provided is an additional modification kit to install a 0.100 inch thickdoubler between Body Station (BS) 910 and BS 930 andbetween Buttock Line (BL) 0 and right BL 10. The incorporation threshold for this service bulletin is shown in the Description andAccomplishmentInstructions. As a result of the FAA-sponsoredAging Fleet Conference, a 727 Structures Working Groupwith Airline and Boeingmembers and FAA observerswas formed to review structural servicebulletinmodifications and recommend selected bulletins for incorporation on aging airplanes. Based on a structural review of the 727 airplane, the Structures Working Group has determined that modification per this service bulletin, at or before the indicated threshold, should be accomplished to support the continued structural integrityof aging 727 airplanes. Airplane effectivity is expanded, to includeall 727 airplanes,and updated to reflect current airplaneownership. Airplanes modified per previous releases of this servicebulletin require inspectionuntil modified to add the additionaldoubler between BS 910 and BS 930 andbetween BL 0 and right BL 10. The original issue of this bulletin was issued, as an Alert Service Bulletin, therefore the "A", is added to thebulletinnumber. This servicebulletin is rewritten to complywith current servicebulletin format and therefore revision bars have been omitted because of the extensive rewrite. REVISION HISTORY Original Issue: May 3, 1974 Revision 1: September 27, 1974 Revision 2: May 2, 1975 Revision 3: November 30, 1989ACTION (PRR23792) Based on a structural review of the 727 airplane, incorporation of the modification per this servicebulletin is recommended on aging airplanes. Three operators reported cracks from 25 to 48 inches long in the Main Landing Gear (MLG)wheelwell pressure floor, resulting in rapid depressurization. Twenty four operators reported 67 airplanes with cracks up to two inches long located in the reinforcingbeads between Body Station (BS) 910 and BS 940 on both sides of the airplanebetween Buttock Line (BL) 10 and BL 50. The airplanes had accumulated between 12,600 and 43,300 flight cycles and 18,000 and 51,600 flighthours. Since Revision 2 five operators reported five airplanes with cracks out of the area covered by the modification of the service bulletin. The cracks were located in the reinforcing beads between BS 910 and BS 930 and between BL 0 and right BL 10. The airplanes had accumulated between 18,200 and 42,100 flight cycles and 21,300 and 39,900 flight hours. Continued operation with undetected cracks could result in loss of cabin pressure. The cracks have been attributed to fatigue. This service bulletin is the subject of Federal Aviation Administration (FAA) Airworthiness Directive 77-13-15,Amendment 39-2944. As recommendedby the 727 Aging Fleet Structures Working Group, accomplish modification per the Accomplishment Instructions at or before the accumulationof 60,000 flight cycles. Inspect pressure floor reinforcing beads adjacent to BS 910 floorbeam of airplanesthathave accumulated 15,000 flights at maintenance intervals as described in the Description and Accomplishment Instructions until accomplishing preventive modification or repair per this service bulletin. Group 2 and 3 airplanes and airplanes previouslymodified require inspection of unmodified areas at 2000 flight cycles intervals until accomplishing preventivemodification or repair per this servicebulletin. If cracks are found within specified limits, accomplish repair per this service bulletin. If cracks exceed specifiedlimits, contact Boeing. If no cracks are found, accomplish the preventive modification per this servicebulletin or repeat inspection at specified intervals until accomplishing preventive modification or repairper this servicebulletin. EFFECTIVITY All 727 airplanes in three groups. Group 1

- Linenumbers 1 through 1102. Group 2

- Linenumbers 1103 through 1477. Group 3

- Linenumbers 1478 through 1832.

Summary Page 1 of 2 BACKGROUNDDETAIL I 

### (PLANVIEW) May 3/74 REV. 3: Nov 30/89 SummaryPage 2 of 2SUBJECT: FUSELAGE

- MAINWHEEL WELL PRESSURE FLOORINSPECTION, MODIFICATIONAND REPAIR

I. PLANNING INFORMATION A. Effectivity 1. AirplanesAffected See ServiceBulletin Index Part 3 for cross referenceof Variable Number toAirplane SerialNumber. This change is applicable to airplanes listedbelow in accordance with PRR 23792. LISTING BY CUSTOMER CODEANDVARIABLENUMBER CODE GROUP VARIABLENUMBER 1 E0301-E0303 E0332 E0348-E0349 QA101-QA141 2 QA142-QA187 3 QA188-QA199 E0305-E0309 E0334 E3075 QA854 E0311-E0326 E0336-E0339 E3519-E3520 QA856-QA869 E0328-E0330 E0345 QA014 QB801-QB810 E3032-E3033E3062 E3148 E3286-E3289 E3651 1 QD205 2 QD206-QD212 3 QD218-QD239 QD215-QD217
1 QA351-QA352QA551-QA556 3 QD761-QD769 QD781-QD782 QA559-QA570

May 3/74 REV. 3: Nov 30/89 727-53A0124 Page 1 of 35 

### AAL

AAT ACE 1 E3029 1 E0130 ACN

AFAVARIABLENUMBER (CONTINUED) 1 E5410 1 QA574-QA576 2 QB451-QB453 3 QB454-QB458 1 E3681 1 E0104 E3145 1 QA040 2 QA044-QA046 1 E0133 1 E0119 3 QD040 2 QD601-QD603 3 QD450 QD034 QD043-QD046 QD604-QD607 1 E3401 QA902 2 QA378 QD931-QD932 3 QB619 QD555 E3521 E5058 QA905-QA906 QA894-QA895 QD902 QD951-QD952 QB622 QB624 QD558 QD909 E5142 QD904-QD905 QB626-QB628 QD953-QD954 1 QD001-QD004 2 QD007-QD009 3 QD010-QD012 2 QD191-QD192 3 QD518 1 E3036 E3221-E3224 E5451 2 QD553-QD554 3 QD581-QD583 1 E0034-E0036 E3246 QA039 3 QD474-QD475 E3068 E3402 E5453 E3141-E3143 E3406 QA572 QD991-QD992 E3024 E3248 QA041-QA043 E3072 E3511 QA853

1 E3038

May 3/74 REV. 3: Nov 30/89 727-53A0124 2 E5424 AFG ALG



### AMA AMJ


### ANA

ANC E0310 E3341 E0342 E5161 E3028 E5403

ANS

ARG


### ASA

AUS

AVG

AVI

AVN

AVO E3204 E3412 QB031

E3244 QA036 QD121 CODE GROUPVARIABLENUMBER (CONTINUED) E3654 E5225 E5405 QD451 QB032-QB033 E3005 E5351-E5352 QD031-QD032 QA897-QA899QB601-QB615 QB616-QB617 1 E3509 1 E3065 1 E3506 1 E0038-E0042 E3241 E5201 QA308-QA314 2 QA341-QA344 3 QA345-QA349 3 QB625 1 E0304 1 QB034 2 QB041-QB046 3 QB047-QB049 1 E3202 E5032 2 QD410 1 E3071 1 QA073-QA079 QA909-QA917 2 QA098-QA099 3 QA939-QA946 1 E3146 QD005 2 QD903 E5112 E3512 E0202 E3245 E5455 QA325-QA340 QA890-QA893 QB901-QB904

E5050 QB036-QB040 QD444 QB051-QB058 E3409 E5042-E5043

E3344-E3345 QA081-QA092 QA919-QA926 QA949 E3149 QD033 QL004-QL005 E5141 E5409 E0205 E3247 QA019-QA021 QA896 E5481-E5483 E5435 E3001 E3253 QA301-QA306

QD085-QD088 QB060-QB064QD571-QD572 E3411 E3415-E3418 E5045

E3781-E3783 QA096-QA097 QA907 QA929-QA933 QB501-QB552 QB553-QB575 QB035 QB114 QD123 QL031-QL032

May 3/74 REV. 3: Nov 30/89 727-53A0124 3 CODE AVT BHR BHT BLA BLG BNF GROUP 1 3 1 1 1 1 2 3 BNR BRS CAF CAL

CAY CKF CMA

CMI

CMR CRU DAL

DANVARIABLENUMBER (CONTINUED) 1 E0030 E5274 E0124 E5382 

### 1 QB105QB110QB115 QB115-QB119 2 QB310-QB316QB351-QB352 E3622 E5402 E5046-E5047 QB301-QB309

1 E0351 1 E3206 1 E3755 2 QD351 E5404

1 E3014 3 QB065 QD452 1 QA601-QA605 QA627-QA643 2 QA644-QA658 3 QA659-QA684 1 E5418 3 QD908 3 QD661-QD663 1 QA573 QA607-QA620 QA622 QA686-QA688

QA855 1 E3101 E5104-E5105 E5281 1 E0201 1 E5353 1 E3704 1 QA901 E3151-E3152 E5108 E5426 E3275-E3276E3652 E5273 E5277
E5241

QA904 1 E0120 E0134-E0138 E3277 E5052-E5054 E5101-E5102 E5242 QD035-QD036 2 QD037-QD039 3 QD041-QD042 E0122-E0123 E3257-E3261 E3283 E5056-E5057 E5163-E5164 E5408 QD201-QD204 QD213-QD214 QL501-QL515 E0125-E0129 E3266-E3267 E3290 E5059-E5063 E5221-E5224 E5420 E0131-E0132 E3273-E3274 E5048-E5049 E5067 E5226-E5240 E5454

May 3/74 REV. 3: Nov 30/89 727-53A0124 4 DHL

DLH

DNV DOC DOM

DON EAD EAL

EKO ESM ETH EUR QA624

EVR

FAA FAM FBT FCT FED CODE GROUPCODE GROUP VARIABLENUMBER (CONTINUED) FMR 1 E3346 FRB 1 E3655 FTL 1 E0331 E0333 E0335 E0343-E0344 E0346-E0347E3070 E3076 E3577 FUN 1 E3419 GEO 1 E0216 GLE 1 E3144 GRP 1 E0101 GTR 1 E3701-E3703QA038 QA908 HAP 1 E3114 E3452 3 QD971-QD972 HAV 1 E3026 E3116 HEM 1 E3077 HTV 1 E3176 IAL 1 QA002 QA359 IBE 1 QB121-QB145QB147-QB149 2 QB151-QB153 3 QB155-QB158 ICC 1 E3064 E3069 ICE 1 E5417 QD006 3 QD791 INI 1 E3150 IRN 1 E0204 E3118 E3472-E 2 QD104-QD105 IRQ 2 QD421-QD423 3 QD424-QD426 JAM 2 QD281-QD284 JAT 1 QD142-QD143 2 QD144-QD145 3 QD146-QD149 May 3/74 REV. 3: Nov 30/89 E0340-E0341 E3073-E3074

QA918

E3473 QD101-QD103

727-53A0124 5CODE 

### JPA JTA JTE

KAB KAL

KBA KEL KEY

KLA KUW LAA

LAB

LAC LDE

LIL LNA 

### MAA MEZ


### MGM MME 

### MXA MXG

May 3/74 REV. 3: Nov 30/89 GRO UP VARIABLE NUMBER (CONTINUED) 1 E0206 1 E0213 E3407 1 E0418 E0420-E0422 E3117 E3205 E3347-E3348 E3350 1 E0103 E0107 1 QA015 QA022 QA024- QA037 1 E3574 1 E5001 E5428 1 E0029 E0033 E3027 E3250-E3252E3571 1 E3604 3 QD801-QD804 1 QA316 2 QA317-QA324 QB651 1 E3102 E3522 E5421 2 QD161-QD163 3 QD701-QD702QD907 1 E0032 E3103 E3517 E5051 E5115 3 QD973 2 QD446 1 E3030 1 E0211 2 QD906 1 E3504-E3505 E3510 1 E0209 1 E3171-E3172 E3174-E3175E3553 1 E3035 E3037 E3201

QA025 QA033-QA035

E3243

E3573

727-53A0124 6VARIABLENUMBER (CONTINUED) 1 E5501 3 QL081 1 E3242 1 QA557-QA558 1 E5279 1 E3021-E3023 E3039-E3040 QA708-QA720 2 QA725-QA745 3 QA746-QA753 E3025 E3031 E3034 E3173 QA701-QA703 QA705-QA706 QA722-QA723 QD441-QD443 QD445 QD447 QD448-QD449 QD453 QD711-QD717 1 E3004 1 QA001 QA801-QA805 1 E0210 E5002 E5036-E5037 E5280 E5423 1 QA003 QA216-QA225 QA707 QB101-QB104 3 QD691-QD692 QA057-QA058 QA366 QA721 QA201-QA207 QA369-QA371 QA851-QA852 QA209-QA214 QA704 

### QB01-QB002 QD821-QD828 1 E3203 1 E3115 1 E3507 1 E3503 1 QA059-QA072 2 QA878-QA889 3 QD512-QD517 QD401 E3621 E5278 QA870-QA877 QD501-QD510

1 QA005-QA009 QA358 2 QA372-QA373 3 QA374-QA376 QA023 QA360-QA365 QA928 QA026-QA032 QA051-QA056 QA367-QA368

May 3/74 REV. 3: Nov 30/89 727-53A0124 7 NAU NGA NMB NOB NOM NWA

OCP OLY OMA ORI 1 E3003 E5031 E5044 E5411 E5004 E5039 E5381 E5433 E5006 E5041 E5401 E5502 PAA

PAF PAN PCT PER PEX

PIE

CODE GROUPUP VARIABLENUMBER (CONTINUED) 1 E0413 2 QD403 1 QA577-QA579 2 QA581-QA584 3 QA585 1 E0212 3 QD407 3 QE002 1 E3285 3 QD124-QD126 1 E3784 E5419 1 E3420 1 E5065 E5068 1 E5035 E5040 1 E5003 E5005 E50 E5415 1 E0414 E3576 1 E3113 1 E0208 E3451 1 E3684 3 QB629 2 QD402 1 E0207 1 E3421 1 QL001-QL003 3 QD164 QD427 QD6 2 QD471-QD473 1 E3513 E3516 E36 3 QD741 07-E5011 E5413

84-QD685QL006-QL008

82

May 3/74 REV. 3: Nov 30/89 727-53A0124 8 GRO CODE PJE QAT RAM

RBA

RBH RGI RJA RNA RNF RNZ 

# RVV RYN

SAE SAH SAK SAN SCA SEN SIG SKL STR

SYR TAMVARIABLENUMBER (CONTINUED) 1 QA093-QA095 QD302 3 QD303-QD304 1 E3013 E3501 1 QD321-QD322 QD324 2 QD325 QD511 3 QD327-QD330 1 E3410 1 E5114 1 E3011-E3012 E3508 1 E3002 1 E3284 3 QD910 1 E0106 E3342-E3343 QA353-QA355 QA625-QA626 E0116 E3349 QA357 E0121 QA010-QA012 QA606 E0140 QA017-QA018 QA623

1 QA571 2 QB402-QB407 1 E0401-E0402 E0416-E0417 QA529-QA537 2 QB204-QB210 3 QB211-QB220 E0404-E0408E0410 E0419 E0423 QB201-QB203 E0412 QA501-QA527

1 E0001 E3262-E3265 2 QA429-QA474 3 QA475-QA499 E0003 E0005-E0028 E3254-E3256 E3268-E3272E3278-E3282QA401-QA428 QB701-QB705 1 E3523 1 E0203 1 E3061 E3063 E3066-E3067 1 E5033-E5034 E5113 E5251-E5252 E5422 2 QA927 3 QA936-QA938 E5038 E5116 E5271 E5427 QA934-QA935 E5106-E5107 E5162 E5275-E5276 E5429 QD551-QD552 E5109-E5111 E5243-E5245 E5301-E5306

May 3/74 REV. 3: Nov 30/89 727-53A0124 9 E3653 TAP

TBL THY

TMI TNN TOS TOU TRD TRI QA004 QA903

TSI

TUN

TWA QB401

UAL



### ULL UO5 U06 UPS

CODE GROUPVARIABLE NUMBER (CONTINUED) 3 QB066-QB068 QB618 QD681-QD683 1 E0215 QB620-QB621 QB623
E3059 1 E3683 1 E3572 E3575 E5406-E5407 E5412 E3751-E3754 E5272

3 QD556-QD557 1 E3006 1 E0350 3 QE001 1 E3601-E3603 3 QD621-QD624 QD641 1 E0214 LISTING BYVARIABLE NUMBER GROUP 1 E0001-E0042 E3001-E3006 E3101-E3103 E3221-E3224 E3471-E3474 E3601-E3604 E3701-E3704 E5101-E5116 E5251-E5252 E5401-E5424 E5481-E5483 QA201-QA225 QA501-QA537 QA851-QA877 QB114-QB119 

### QD01-QD006 QD141-QD143 QL001-QL003 E0101-E0140 E3011-E3014 E3111-E3118 E3241-E3290 E3501-E3513 E3621-E3622 E3751-E3755 E5141-E5143 E5271-E5281 E5426-E5429 E5501-E5502 QA301-QA316 QA551-QA579 QA901-QA918 QB121-QB149 QD031-QD036 QD201-QD205 E0201-E0216 E3021-E3040 E3141-E3152 E3341-E3350 E3516-E3523 E3651-E3655 E3781-E3784 E5161-E5164 E5301-E5306 E5433 QA001-QA043 QA325-QA340 QA601-QA643 QB001-QB002 QB201-QB203 QD085-QD088 QD301-QD302 E0301-E0351 E3059 E3171-E3177 E3401-E3421 E3551-E3553 E3677 E5001-E5011 E5201-E5203 E5351-E5353 E5435 QA051-QA097 QA351-QA371 QA701-QA724 QB031-QB040 QB301-QB309 QD101-QD103 QD321-QD324 E0401-E0423 E3061-E3077 E3201-E3206 E3451-E3452 E3571-E3578 E3681-E3684 E5031-E5068 E5221-E5245 E5381-E5382 E5451-E5455 QA101-QA141 QA401-QA428 QA801-QA805 QB101-QB110 QB401 QD121-QD123 QD401

May 3/74 REV. 3: Nov 30,89 727-53A0124 10 

### USA

USV VAC 

### VAR

VSP VTC 

### WEF WST WWC 

### YEM ZAR CODE GROUPLISTING BYVARIABLENUMBER (CONTINUED) GROUP 2 QA044-QA046 QA372-QA373 QA725-QA745 QB204-QB210 QB501-QB552 QD104-QD105 QD281-QD284 QD421-QD423 QD601-QD603 QL031-QL032 QA098-QA099 QA378 QA878-QA899 QB310-QB316 QB601-QB615 QD144-QD145 QD325-QD326 QD441-QD447 QD901-QD906 QA142-QA187 QA429-QA474 QA919-QA935 QB351-QB352 QB651 QD161-QD163 QD351 QD471-QD473 QD931-QD932 QA317-QA324 QA581-QA584 QB041-QB046 QB402-QB407 QD007-QD009 QD191-QD192 QD402-QD403 QD501-QD511 QD951-QD952 QA341-QA344 QA644-QA658 QB151-QB153 QB451-QB453 QD037-QD039 QD206-QD217 QD410 QD551-QD554 QL004-QL005

GROUP 3 QA188-QA199 QA659-QA688 QB051-QB068 QB616-QB629 QD040-QD046 QD303-QD305 QD474-QD475 QD604-QD607 QD691-QD692 QD781-QD782 QD953-QD954 QL081 QA345-QA349 QA746-QA753 QB154-QB158 QB701-QB705 QD124-QD127 QD327-QD330 QD512-QD518 QD621-QD624 QD701-QD702 QD791 QD971-QD973 QL501-QL515 QA374-QA376 QA936-QA946 QB211-QB220 QB801-QB810 QD146-QD149 QD407 QD555-QD558 QD641 QD711-QD717 QD801-QD804 QD991-QD992 QA475-QA499 QA949 QB454-QB458 QB901-QB904 QD164 QD424-QD427 QD571-QD572 QD661-QD663 QD741 QD821-QD828 QE001-QE002 QA585 QB047-QB049 QB553-QB575 QD010-QD012 QD218-QD239 QD448-QD453 QD581-QD583 QD681-QD685 QD761-QD769 QD907-QD910 QL006-QL008 2. SparesAffected None

May 3/74 REV. 3: Nov 30/89 727-53A0124 11B. Reason As a result of the FAA-sponsored Aging Fleet Conference, a 727 Structures Working Group with Airline and Boeing members and FAA observers was formed to review structural service bulletin modifications and recommend selected bulletins for incorporation on aging airplanes. This service bulletin modification has been recommended for incorporationon aging 727 airplanes. Incorporation of the preventive modification described in this bulletin will reduce thepossibility of cracks in thenain gear wheel well pressure floor adjacent to the floorbeams at BodY Stations (BS) 900, 910 and 920. If cracks occur andprogress undetected, they could result in rapid loss of cabinpressurization. Three operators reported cracks from 25 to 48 inches long in theMain Landing Gear (MLG) wheel well pressure floor, resulting in rapid depressurization. Twenty four operators have reported 67 airplanes with cracking in the reinforcingbeads between BS 910 and BS 940 on both sides of the airplane between Buttock Line (BL) 10 and BL 50. The airplanes had accumulatedbetween 12,600 and 43,300 flight cycles and 18,000 and 51,600 flighthours. Since Revision 2 five operators reported five airplanes with cracks outside of the area covered by the modification of the service bulletin. The crackswere located in the reinforcingbeads between BS 910 and BS 930 and between BL 0 and right BL 10. The airplaneshad accumulated between 18,200 and 42,100 flight cycles and 21,300 and 39,900 flighthours. Revision 1 was issued to add the installation of stiffening straps at BS 910 to the preventive modification. Also added was a new repair doubler that extendedbeyond the flanges of the floorbeams. Revision 2 was issued to add the installation of stiffening straps at BS 910 and 920. Also added was new repair straps that install over the doubler at each floorbeam. Revision 3 is issued toprovide the recommendation of theAging Fleet 727 Structures Working Group. Also provided is an additional modification kit to install a 0.100 inch thickdoubler between BS 910 and BS 930 andbetween BL 0 and right BL 10.

May 3/74 727-53A0124 REV. 3: Nov 30/89 12C. Description Based on a structural review of the 727 airplane, it is recommended that the modification perAccomplishment Instructions of this service bulletin be accomplished prior to, or upon accumulation of 60,000 flight cycles Inspectpressure floor adjacent to Body Station (BS)910 floorbeam at orprior to 15,000 flights and thereafterat maintenance intervals of 2000 flight cycles or lessuntil accomplishingpreventivemodification or repair per this service bulletin. Airplanes exceeding this threshold shouldbe inspectedwithin 800 flight cycles after receipt of this Revision. Group 2 and 3 airplanes and airplanes previously modified require inspection of unmodified areas within 800 flight cycles after receipt of this Revision and thereafter at 2000 flight cycle intervals or less until installing the 0.100 inch thick doubler between BS 910 and BS 930 andbetween Buttock Line (BL) 0 and right BL 10per thisRevision 3. If avisual inspectionisperformed and evidence of cracking or flaked paint is detected, verify cracked condition with eddy current or penetrant inspectionmethod. If cracks are detected, perform similar inspection of pressure floor adjacent to BS 900 and 920 floorbeams and install repair doublers as requiredprior to next flight. Alternately, If cracks do not exceed limits specified in TableV, stop drill and seal cracks and install repair doubler within 600 flights. Repeat inspection of unrepaired areas at maintenance intervals of 2000 flight cycles or less until accomplishing the preventivemodification or repair per this service bulletin. Ifno cracks are found, accomplish themodification per this Revision 3 or repeat inspectionat 2000 flight cycle intervals. Group 2 and 3 airplanes had reinforcement straps installed on the pressure floor at Stations 900, 910 and 920 duringproduction. Group 3 airplanes had different flap control pulley installed at Station 918 and right Buttock Line 12.

May 3/74 727-53A0124 REV. 3: Nov 30/89 13This service bulletin is the subject of Federal Aviation Administration (FAA) Airworthiness Directive 77-13-15, Amendment 39-2944. NOTE: 1. Contact Boeing for instructions if any damaged areas exceed the specified limits. To expedite Boeing response, be specific when defining and locating the damage. Circumstances leading up to the damage and any secondary effects, when known should be included in the communication and followed up by sketches and photographs when appropriate. In addition, where corrosion is involved, length, width, and greatEAstdepth of clean-up are required. CONTACT: BOEING COMMERCIALAIRPLANES ATTENTION: MANAGER,AIRLINE SUPPORT 2 Due to the corrosion conductive environment of the area and since corrosion could aggravate theproblem described herein, it is suggested that the operator initiate a program of corrosionpreventive maintenance in the wheel well, including inspection and restoration of the protective finish and application of water displacing corrosion inhibiting compound,with special emphasis upon the ends of all reinforcingbeads in the pressure floor. (See Corrosion Prevention Manual, Part II, Subject 53-30-27, Figure 5). 3. This service bulletin is listed in Boeing Document D6-54860 4. Concurrent incorporation of Service Bulletin 727-53-0149 is suggesteddue to similar access requirements.

May 3/74 REV. 3: Nov 30/89 727-53A0124 14D. Approval This service bulletin has been reviewed by the Federal Aviation Administration (FAA) and the repairs and modifications herein comply with the applicable FederalAviation Regulations (FAR's) and are FAA approved. The interim repair or deferral of repair described in Accomplishment Instructions, has FAA approval contingent on accomplishment of the inspections at the intervals specified in the Accomplishment Instructions. The FAAhas determined thatmodification, inspection, and/or repair in accordancewith Revision 3 to Service Bulletin 727-53A0124, "FUSELAGE

- MAIN WHEEL WELL PRESSURE FLOOR INSPECTION,MODIFICATIONAND REPAIR" is an acceptable alternate means of compliance for Airworthiness Directive (AD) 77-13-15,Amendment 39-2944. The FAA has determined that modification and/or repair in accordance with Revision 3 to Service Bulletin 727-53A0124, "FUSELAGE

- MAIN WHEEL WELL PRESSURE FLOOR INSPECTION,MODIFICATION AND REPAIR" is an acceptable alternate means of compliance for the modifications specified in Boeing Document D6-54860,which is the subject of Notice of ProposedRuleMaking (NPRM)DocketNumber 89-NM-60-AD.

May 3/74 REV. 3: Nov 30/89 727-53A0124 15E. Manpower Approximately 222 man-hours are required to accomplish this modificationper airplane . The following breakdown of manpower requirements is suggested as a guide to assist operators in planning and accomplishing this modification. This estimate is for direct labor performed by an experienced crew. It does not include setup, planning, familiarization, cure time, part fabrication, tool acquisition, or lost time. Factor this estimate as necessary based on your own experience.

Operation Crew size Inspection 2 Man-Hours 2 Elapsed Time (Hours) 2 Modification Access Installation Restoration Operational and Leak Checks TOTAL PERAIRPLANE

May 3/74 REV. 3: Nov 30/89 8 6 8

4 32 126

48

16 222 4 21

6

4 35

727-53A0124 16F. Material - Price andAvailability 1. The following kit identified in Paragraph II.A may be obtained from Boeing within the terms and conditions definedbelow. The quotation indicates the quantity and date when initial kit will be available. When source capacity is limited and tooling or material availability is the pacing factor, operator purchase orders will receive an allocation from the available quantities based on receiptdate ofpurchase orderby the Spares Department and based on operator's planned modification schedules. Therefore, operators are requested to include planned dates of incorporationon their purchase orders. When initial quantities are depleted, additional kits will be available as indicated in the Reorder Lead Time (ROLT) column. Reorder lead time is computed fromdate of receipt of operator'spurchase orders. Kit Number Desc 65-89360-128 Kitcription Date Dec 8, 1989 ROLT Qty Weeks Unit Price 100 22 $283.00 DateNovember 30. 1989 The prices quoted are subject to the terms and conditions of Boeing's standardpurchase order acknowledgement. Quotations are subject to acceptancewithin 120 days from date hereon. After expiration of the quotation, price and delivery data will be provided upon request. Prices quoted in United States Dollars. Terms: Net 30days. Address purchase orders and correspondence pertaining to this quotation to Director of Spares, and refer to this service bulletinnumber.

May 3/74 REV. 3: Nov 30/89 727-53A0124 172. The following kits identified in Paragraphs II.A and II.Bmay be obtained from Boeing within the terms and conditions defined below. The quotation is computed from date of receipt of operator'spurchase orders. Improved flow timesmay be possible ifnecessary to support operator'splannedmodification schedule. Therefore, operators are requested to include planned dates of incorporationon theirpurchase orders. Kit Number 65-89360-5 65-89360-6 65-89360-7 65-89360-8 65-89360-9 65-89360-10 65-89360-11 65-89360-12 65-97861-1 65-97861-2 65-97861-3 65-97861-4 65-97861-5 65-97861-6 Description Kit Kit Kit Kit Kit Kit Kit Kit Kit Kit Kit Kit-Supplemental Kit-Supplemental Kit Delivery 37 37 37 37 37 37 37 37 Inactive Inactive Inactive 20 20 22 Unit Price 

# $358.00 $358.00 $184.00 $184.00 $288.00 $288.00 $528.00 $528.00 forprocurement forprocurement forprocurement $1212.00 

# $271.00 $2906.00 Date November 30. 1989 The prices quoted are subject to the terms and conditions of Boeing's standardpurchase order acknowledgement. Quotations are subject to acceptancewithin 120 days from date hereon. After expiration of the quotation, price and delivery data will be provided upon request. Prices quoted in United States Dollars. Terms:Net 30days. Address purchase orders and correspondence pertaining quotation to Director of Spares, and refer to this bulletinnumber. to this service

G. Tooling - Price andAvailability None H. Weight and Balance

Applicability 65-89360-128 65-97861-6 Change in Weight (Pounds) 

# +3.6 +17.4 Change in Moment (Pound-Inches) 

# +3312 +15860

May 3/74 REV. 3: Nov 30/89 727-53A0124 18I. References 1. Existing Data:
a. EngineeringChangeMemo PRR 23792 b. 727 StructuralRepairManual Subjects 51-30-02 and 51-30-05 c. Corrosion PreventionManual, Part II, Subject 53-30-27, Figure 5 d. Boeing StandardOverhaul PracticesManual 20-50-12 e. Boeing ServiceBulletin 727-53-0149, "FUSELAGE

- MAINWHEEL WELL PRESSURE FLOOR INSPECTION,MODIFICATIONAND REPAIR" f. FAAAirworthinessDirective 77-13-15,Amendment 39-2944 g. Boeing Document D6-54860 "AgingAirplane Service Bulletin StructuralModification Program

-Model 727" 2. Data supplied in supportof this servicebulletin:
a. Drawings: DrawingNo. Sheet DCN ADCN Title 65-18745 3 J 29,30 PressureFloor 31,32 InstallationMain Gear 33 Wheel Well, Sta 870-950 65-89360 2 A 1 Doubler Installation

- 3 C 1 Main GearWheelWell 4 7 3. Process Data: Boeing Process Specifications that are listed on drawings supplied in support of this servicebulletin are not detailed in this servicebulletin since they are common practices which can be accomplishedin accordancewith operator'snormalprocedures. J. PublicationsAffected Publication Chapter-Section 727 StructuralRepairManual.................. 53-10

May 3/74 727-53A0124 REV. 3: Nov 30/89 19II. MATERIAL INFORMATION A. Parts Required PerAirplane NOTES: 1. The following kits inTable IImay be obtained asnoted Paragraph I.F. or components may be fabricated, described, or obtained from operator's inventory industry sources,as desired. 2. The following kits and operator furnishedmaterials listed in Paragraph II.A.2 are required tomodify each airplane. Table II KitApplicability Applicability KitNumber Preventive Modification Sta 900, 910 and 920, left and right sides 65-97861-6 65-97861-3 Supersedes 65-97869-3. Inactive for future procurement. Supersedes 65-97869-1. Kit 65-97861-3 together with 65-89360-128 is equivalent to 65-97869-6 Sta 910, left and right sides

Sta 900 and 920, and right sides

Sta 910 to 930 left 65-97861-1

65-97861-4

65-89360-128 Inactive for future procurement. Supplemented by 65-97861-4. Inactive for future procurement. This kit togetherwith 65-97869-1 is equivalent to 65-97869-3. This kit togetherwith 65-97869-3 is equivalent to 65-97869-6.

May 3/74 REV. 3: Nov 30/89 727-53A0124 20 in as or

Usage RemarksMay 3/74 REV. 3: Nov 30/89 727-53A0124 21May 3/74 REV. 3: Nov 30/89 

### 727-53A0124 2265-89360

- KIT, DOUBLER INSTALLATION,PRESSURE FLOOR,MAIN GEARWHEEL WELL -8 -7 -6 Quantity -5 -1 PartNumber Nomenclature 65-89360-1 65-89360-5 65-89360-6 65-89360-7 65-89360-8 2 2 2 2 2 65- 9 2 20-2(c) 1 1 1 65- 9 2 20-56(c) 2 2 2 2 2 6 5

-9 220-57(c) 1 65-89360-2 2 65-89360-3 1 1 1 65-89360-4(d) 1 65-89360-13(d) 1 65-89360-14(d) 1 65-89360-15(d) 1 65-89360-16(d) 2 2 65-89360-21(d) 1 1 2 2 1 69-41867-1 1 1 2 2 1 90-4007-3009 2 2 2 6 4 BACB30FP6-5 4 13 11 BACB30FP6-6 2 2 2 BACB30FP6-7 2 2 2 2 BACB30FP8-5 4 8 4 BACB30FQ6-6 2 BACB30NE4-6 6 6 17 27 21 BACC30M6 6 6 6 6 BACC30M8 4 4 8 8 4 BACR15BB4A6(b) 6 6 6 6 BACR15BB8D10 6 6 6 6 4 BACR15BB8D12(a) 8 8 8 8 BACR15CE6D8 8 8 8 8 BACR15CE6D12 65-89360-9 65-89360-10 65-89360-11 65-89360-12 65-89360-128 1 65-89360-134 1 2 2 2 2 6 5

-9 2 20-2(c) 1 1 65

-9220-56(c) 2 2 65

-9 2 20-57(c) Kit Kit Kit Kit Kit Rivet Kit RivetKit RivetKit Doubler Filler Filler Doubler Doubler Doubler Doubler Filler Retainer Seal Bolt Bolt Bolt Bolt Bolt Bolt Collar Collar Rivet Rivet Rivet Rivet Rivet Kit Kit Kit Kit Kit Bracket Installation RivetKit Rivet Kit Rivet Kit

May 3/74 REV. 3: Nov 30/89 727-53A0124 2365-89360
- (CONTINUED) -134 -128 -12 -11 Quantity -10 -9 PartNumber Nomenclature 50-3361-2024 50-3361-38 1 1 65-89360-4(d) 1 65-89360-17(d) 1 65-89360-18(d) 1 65-89360-19(d) 2 1 65-89360-20(d) 2 2 65-89360-21(d) 1 . 65-89360-131 1 . 65-89360-132 1 65-89360-133 66-17308-1 69-20207-1 69-20207-3 69-20207-4

. 1 1 69-41867-1

. . 1 1 90-4007-3009 AN320-5 AN380-2-1 AN960-10L AN960D516

. . . . . AN960PD10 4 . BACB30FN6A6U 2 2 6 4 BACB30FP6-5 13 . 11 BACB30FP6-6 2 2 2 BACB30FP6-7 2 2 2 BACB30FP8-5 4 8 4 BACB30FQ6-6 2 BACB30NE4-6 4 BACB30FP6A5 2 .. BACB30FP6A6 6 6 17 27 21 BACC30M6 6 6 6 BACC30M8 BACP18C-DD3-178 BACP30J7 4 8 8 4 BACR15BB4A6(b) 6 6 6 BACR15BB8D10 19 6 6 6 4 BACR15BB8D12(a) 10 . . . BACR15BB8D14 8 8 8 BACR15CE6D8 8 8 8 . BACR15CE6D12 NAS1105-22D NAS623-3-3 NAS679A3W MS20220-2 MS24665-132 Radius Filler Radius Filler Filler Doubler Doubler Doubler Doubler Filler Doubler Clip Clip Fairlead Bracket Bracket Bracket Retainer Seal Nut Pin Washer Washer Washer Bolt Bolt Bolt Bolt Bolt Bolt Bolt Bolt, 1/64 OS Bolt, 1/64 OS Collar Collar Pin Pulley Rivet Rivet Rivet Rivet Rivet Rivet Bolt Screw Nut Pulley Cotter Pin

May 3/74 REV. 3: Nov 30/89 727-53A0124 24 2 2

2 1 1 1

1 3 1 1 4

1 2

1 4 4 2 365-97861

- KIT, STRAP INSTALLATION,PRESSUREFLOORMAIN GEARWHEELWELL -6 -5 -4 -3 Quantity -2 -1 PartNumber Nomenclature 65-97861-1 65-97861-2 65-97861-3 65-97861-4 65-97861-5 65-97861-6 65-9220-2(c) 65-18745-415(d) 65-18745-416(d) 65-18745-417(d) 65-18745-418(d) 1 65-18745-419(d) 1 65-18745-420(d) 65-18745-421(d) 65-18745-422(d) 65-18745-423(d) 65-18745-424(d) 65-18745-425(d) 65-18745-426(d) 65-18745-427(d) 65-18745-428(d) 65-18745-429(d) 1 65-18745-430(d) 1 65-18745-431(d) 1 65-18745-432(d) 1 65-18745-433(d) 65-89360-11 65-89360-12 65-89360-19(d) 65-89360-20(d) 65-89360-128 Kit Kit Kit Kit Supplemental Kit Supplemental Kit RivetKit Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Strap Subkit Subkit Strap Strap Subkit

May 3/74 REV. 3: Nov 30/89 727-53A0124 25 2 1 1 1 1 1 1 2 1 2 2 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 2 2 1 1 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2

1 1 165-97861

- (CONTINUED) -6 -5 -4 -3 Quantity -2 -1 PartNumber Nomenclature BACB30FP6-6 BACB30FP6-7 BACB30FP6-8 BACB30FP8-7 BACB30FP8-9 BACB30FQ6-7 BACB30FQ6-8 BACB30MC6-7 BACB30MC8-6 BACB30NE4-8 BACC30M6 BACC30M8 BACC30X6 BACC30X6 BACR15CE6D7 212 MS20470D6-12(a) MS20470D6-14(a) MS20470D8-12(a) MS20470D8-14(a) (a) MS20470D( )-( ) rivet and BACR15BB( )D( ) or BACR15ET( used interchangeably. )D( ) rivet may be (b) MS20470A( )-( ) rivet optional to BACR15BB( )A( ) rivet. (c) Contents of rivet kits are approximatelyas indicated in Table III. (d) Indicated parts may be locally fabricated per drawings supplied with this bulletin from 2024-T3 clad sheet per Specification QQ-A-250/5, stock size as noted in Table IV. After trimming to shape, apply chemical film treatment (Alodine or Iridite) and apply one coat of chemical and solvent resistantprimer (Ref BMS 10-11, Type I). TABLE III RivetKit Contents PartNumber 65-9220-2 BACR15BB6D7 BACR15BB6D8 BACR15BB6D10 BACR15BB6D12 BACR15ET7D7 BACR15ET7D8 BACR15ET7D12 31 26 45

34 RivetKit Quantity 65-9220-56 65-9220-57 67 62

13 12

May 3/74 REV. 3: Nov 30/89 727-53A0124 26 4 4 4 8 18 1 4 16 4 18 1 16 562 96 25 16 2 4 4 4 4 4 4 8 18 1 4 10 16 4 18 1 16 350 96 6 25 16 4 4 4 4 8 18 1 4 16 4 18 1 16 562 96 25 16 Bolt Bolt Bolt Bolt Bolt Bolt Bolt Bolt Bolt Bolt Collar Collar Collar Collar Rivet Rivet Rivet Rivet Rivet2. The followingmaterials are tobe furnishedby the operator. PartNumber or Quantity Specification Nomenclature 1/2 Pint BMS 5-14(a) Adhesive 4 Quarts BMS 5-95(a) Sealant 1/2 Pint Q30-121(b) Adhesive (a) Refer to applicable Boeing Material Specification for qualifiedproducts. (b) Dow-Corning Corporation 3901 South SaginawRoad Midland,Michigan 48641-2721 (71984)

May 3/74 727-53A0124 REV. 3: Nov 30/89 27B. PartsRequired toModify Spares None C. Special Tools and EquipmentRequired No special tools or equipment are required to accomplish this bulletin. Maintenance and overhaul tools may be required per any manuals that are listed in Paragraph I.I., References, of this bulletin. Operators should review their tool inventoryto ensure tool availability. D. Existing PartsAccountability None

May 3/74 REV. 3: Nov 30/89 727-53A0124 28III.ACCOMPLISHMENT INSTRUCTIONS NOTES: l.Observe all warning and caution notes in the referenced manual sections. 2.As recommendedby the 727 Aging Fleet StructuresWorking Group, accomplish the modification per this service bulletin, Part III of the Accomplishment Instructions prior to, or upon the accumulationof 60,000 flights. Part I
- Inspection A. Inspectpressure floor adjacent to Body Station 910 for cracks inboth the right and leftmainwheelwellsper Figure 1. B. If no cracks are found, repeat inspection at maintenance intervals of 2000 flight cycles or less, until modified per Part III Preventive Modification. C. If cracks are found, perform similar inspection of ends of beads in pressure floor just forward and aft of Station 900 and 920 floor beams. Repair all cracksper Part II

-Repair, and repeat inspection ofunrepaired areas at maintenance intervals of 2000 flight cycles or less, until modified per Part III Preventive Modification. Optionally, if cracksdo not exceed limits specified in Table V, stop drill cracks with 0.190 inch diameter drill, apply pressure and environmental sealant per operator's standard procedures and repair per Part IIwithin 600 flight cycles. TABLEV Crack Limits Condition Crack Limit Onebead cracked andno cracks in 1.00 inch adjacentbeads. Two adjacentbeads cracked andno cracks 1.00 inch, combined inbeads onboth sides of crackedpair length Three ormore adjacentbeads cracked. 0.35 inchperbead D. If preventive modification straps have been installed at BS 910 only per Revision 1 of this service bulletin, inspect floor adjacent to Body Stations 900 and 920 at maintenance intervals of 2000 flight cycles or less,until preventive modification or repair is installed at these stations also. E. If repair was installed per the original issue of this bulletin, inspect those areas of the pressure floor adjacent to Body Station 900, 910 and 920, which are not covered by the repair doubler, at maintenance intervalsof 2000 flight cycles or less,until terminating action or preventive modification straps or additional repair, as applicable, are installedat these stations. May 3/74 727-53A0124 REV. 3: Nov 30/89 29F. On Group 2 and 3 airplanes and on Group 1 airplanes preventively modified per previous issues of thisbulletin, inspect those areas of the pressure floor between Body Station 910 and 930 and between Buttock Line 0 and right Buttock Line 10, at maintenance intervals of 2000 flight cycles or less, until repaired per Part II or preventive modificationdoubler is installedper Part III.B. Part II - Repair A. Install repair doublers and straps as follows and per Drawing 65-89360, Sheet 3, which details separate doubler and strap configurations suitable for repair of cracks between Stations 900 and 910 only (Kit 65-89360-7 or -8), between 910 and 920 only (Kit 65-89360-9 or -10) or between 900 and 910 as well as between 910 and 920 (Kit 65-89360-5 or -6). B. If expedited repair is required, thedoublermay be installed,without gaining access to the upper surface of thepressure floor,with blind bolts, BACB30LB( )-( ), orVisu-Lok PLT210 or PLT 211blind rivets, at all fastener locations. If blind fasteners are installed, however, they must be reinspected at intervals of approximately 2000 flight cycles until replacedwith fasteners specified of Drawing 65-89360 at or prior to 10,000 flight cycles. Install blind bolts (Ref. 727 StructuralRepair Manual, Subjects 51-30-02 and 51-30-05). Hole sizes for installation ofblind rivets are specified in TableVI. Airplanes previously repaired that have utilized blind fasteners and have exceeded 10,000 flight cycles should replace blind fasteners with solid fasteners within 2000 flights cycles after receipt of this Revision. NOTES: 1. Shorter or longerdoublers than those included in thekits and shown on Drawing 65-89360, Sheet 3, may be installed as a repair. 2. If existing repair doubler interfereswith new repair, it will be necessary to remove existing repair doubler and installnew repair that encompasses the old repair area. 3. Straps and their attaching fasteners included in preventivemodificationKit, 65-97861-3or equivalent, are to be used with the referenced repair kits, since duplicate strapshavenotbeen provided. 4. Installation of the repair doubler described in the original issue of this bulletin and as shown on Drawing 65-89360, Sheet 2, is adequate for repairbut isno longer recommended because of the extensive rework required to accomplish subsequent terminating action.

May 3/74 727-53A0124 REV. 3: Nov 30/89 30May 3/74 REV. 3: Nov 30/89 727-53A0124 31Part III
- PreventiveModification NOTE: If not accomplished, perform inspection per Part I and accomplish preventivemodification or repair as required. A. In areas of floorbeams at Body Stations (BS) 900, 910And 920 which are not coveredby repairs, install Straps, 65-18745-415 through -433 ofKit 65-97861-6or equivalentper Drawing 65-18745, Sheet 3, Drawing 65-89360, Sheet 7, and as follows: 1. Trim straps asnecessary to accommodate existing repairs. Apply chemical film treatment (Alodine or Iridite) and one coat of chemical and solvent resistantprimer (Ref BMS 10-11, Type I) to bare surfaces. 2. At locations designated "BM", remove existing fastener and install MS20470D( )-( ) rivet. At locations designated "XF", install BACB15CE( )D( ) rivet. 3. Remove and reinstallAPU generatorhoist fitting at BS 900, Left Buttock Line (LBL) 18, With four BACB30FP6-8 bolts and BACC30M6 collars installed in 0.200 (+0.003 or -0.000) inch diameter holes. 4. At theAPU hoist attachpoints at BS 900,RBL 28 and BS 920. RBL 51, remove radius filler attaching fasteners and install four Bolts BACB30FQ6-8 and collars BACC30M6 at each station in 0.200 (+0.003 or -0.000) inch diameter holes. Replace existing bolts with BACB30NE4-8bolts (2places each station). 5. Remove two intercostal tee attach fasteners at BS 900, right and left BL 30 and install Bolts BACB30FP6-7 and Collars BACC30M6 in 0.200 (+0.003or -0.000) inchdiameterholes. 6. Remove two intercostal tee attach fasteners at BS 900, right and left BL 46 and install bolts BACB30FP8-7 or -9 and collars BACC30M8 in 0.263 (+0.003or -0.000) inchdiameterholes. 7. Remove hydraulic tubing support bracket attach fasteners at BS 900, LBL 54 and install bolt BACB30MC8-6 and collar BACC30X8 in 0.263 (+0.003or -0.000) inchdiameterhole. 8. At BS 920, remove the nine aft fasteners at locations common to thenew strapsbetween right and left BL 20 and BL 30 and replace with BACB30MC6-7 bolts and BACC30X6 collars installed in 0.200

(+0.003or -0.000)inchdiameterholes. 9. Apply one coat of white enamel (Ref BMS 10-11, Type II) to installed straps.

May 3/74 727-53A0124 REV. 3: Nov 30/89 32B. In area between Body Stations (BS) 910 and 930 and between Buttock Line (BL) 0 and right BL 10which arenot coveredby repairs, install Doubler 65-89360-131per Drawing 65-89360, Sheet 7 and as follows: 1. Trim ends of Straps 65-18745-428, -429, -430, and -431 installed in step III.B. as shown in zone Dll. Apply chemical film treatment (Alodine or Iridite) and one coat of chemical and solvent resistantprimer tobare surface. 2. Remove and discard existing pulley bracket assembly 65-26196-3 two angles 65-18745-234and filler 65-18745-225. 3. Remove existing fasteners as indicated on drawing installation 65-89360-128shown in zone B10. 4. Remove and discard bracket 69-20207-3 from pulley bracket 69-20207-1. 5. Position doubler 65-89360-131 and drill No. 11 (0.191 inch diameter) hole at locationsdesignated "XZK 6", and drill No. F (0.257 inchdiameter)hole at locationsdesignated "XZK8". 6. Install doubler 65-89360-131, two angles 65-18745-234, filler 65-18745-225,bracket 69-20207-4, 65-89360-132, and 65-89360-133 using fastener BACR15BB( )D( ) at locationsdesignated "XZK"with manufacturedhead on upper side ofweb. 7. Apply one coat of white enamel (Ref BMS 10-11, Type II) to installeddoubler. 8. Installpulley bracket 69-20207-1and two fairleads66-17308-1. 9. Group 1 and 2 airplanes

- Install two flap control pulleys MS20220-2. 10. Group 3 airplanes

- Install two flap controlpulleys BACP30J7. 11. Adjust flap controlpulleys ( on Group 1 and 2) MS20220-2 or (on Group 3) BACP30J7 to align with outboard trailing edge flap controlvalve assembly 65-23552-()and inboard flap control shaft assembly 65-24593-().

May 3/74 727-53A0124 REV. 3: Nov 30/89 33Part IV - TerminatingAction ForAirplanesRepaired Per Original Issue or Revision 1 of this servicebulletin A. If repair doubler was installed between Body Station (BS) 900 and BS 910 or between BS 910 and BS 920 per original issue of this bulletin, install straps of Kit 65-89360-11, or equivalent, at the forward and aft edges of the doubler per Drawing 65-89360, Sheet 4, and as follows: 1. If repaired, cut straps to length and apply chemical film treatment (Alodine or Iridite) and one coat of chemical and solvent resistantprimer (RefBMS 10-11, Type I) tobare surface. 2. Apply one coat of white enamel (Ref BMS 10-11, Type II) to installed straps. B. If repair doubler was installed between BS 900 and BS 920 per the original issue of thisbulletin, install straps of Kit 65-89360-12 at forward and aft edges of doubler per Drawing 65-89360, Sheet 4, and install strap and fasteners of preventivemodification Kit 65-97861-3 at BS 910per Drawing-65-89360, Sheet 3 and StepsA.1 and A.2 above. C. If repair doubler was installed per Revision 1 of this bulletin, install straps and fasteners ofpreventivemodificationKit 65-97861-6 at applicable floor beam stationsper Drawing 65-89360, Sheet 3, and StepsA.1 andA.2 above.

May 3/74 REV. 3: Nov 30/89 727-53A0124 34FIGURE 1. INSPECTIONOF MLGWHEELWELL PRESSUREFLOOR May 3/74 REV. 3: Nov 30/89 727-53A0124 35

### 727-53A0124 (REV. 3) S/B DATED:NOVEMBER 30, 1989 

### FUSELAGE

- MAIN WHEELWELL PRESSUREFLOOR INSPECTION, MODIFICATONANDREPAIR AIRPLANESAFFECTED (checkone): TITLE: PREPARED BY: ORGANIZATION: EVALUATION: per S/B effectivity list per corrected listbelow: DATE: TELEX CODE: check ONE of the following checkONE of the following

five circles seven circles.



## - Will accomplish - Inspection

- Being accomplished

- Partial incorporation

- Have accomplished

- Completeincorporation

- Servicebulletinintent

- Willnot accomplish

- Decisiondeferred (explain)

- Other (explainbelow) 

### notjustify 

## COMMENTS: Bulletin Quality, SuggestedImprovements,Other.

FORADDITIONAL COMMENTSUSEREVERSE SIDE Please forward this form toyour Boeing Field ServiceRepresentativeor mail 

### directly to: Boeing CommercialAirplanes P.O. Box 3707 Seattle, WA 98124 Attention: R. G.Kelsey Manager, Service Bulletin Engineering Mail Stop 2L-02 S/B NO.: TITLE:
OPERATOR: