# Boeing Alert Requirements Bulletin 737-53A1402 RB: Revision 1

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- Document: [Boeing Alert Requirements Bulletin 737-53A1402 RB](https://openairdocs.org/service-documents/boeing/737-53a1402-rb.md)
- Title as filed: RB 737-53A1402
- Pages: 64
- PDF: https://openairdocs.org/files/sha256/70/3b/703bca0e8c2eed1c9754282de0e0dc319dfd5697ef2df17f192aa35232f19299
- Page: https://openairdocs.org/service-documents/boeing/737-53a1402-rb/file/703bca0e8c2e

## Text

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### Page 1

Commercial 
Airplanes
737
Requirements Bulletin
ALERT
Number: 737-53A1402 RB
Original Issue: July 02, 2021
ATA System: 5311
SUBJECT: FUSELAGE - Frames and Bulkheads - Shimming Non Conformities at STA 727 Frame
Inner Chord and S-18A Web Inspection
Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15
CFR 300-774). An export license may be required before it is used for development, production or use by foreign
persons from specific countries. The controller of this data has the individual responsibility to abide by all export
laws.
9E991ECCN:
Copyright © 2021 Boeing.
Unpublished Work. All Rights Reserved.
Treatment of this document and its content is governed by contract with Boeing. Rights to use this document
are licensed on a per aircraft basis and such rights may not be transferable. For more information, contact The
Boeing Company.
Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner,
BBJ, DC-8, DC-9, DC-10, KC-10, KC-46, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8, Poseidon and
Boeing liveries are all trademarks owned by The Boeing Company; and no trademark license is granted in
connection with this document unless provided in writing by Boeing.
Original Issue: July 02, 2021
737-53A1402 RB
1 of 64
3.0

### Page 2

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
2 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT
BLANK PAGE

### Page 3

Table of Contents
1. EFFECTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
A. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
B. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2. CONCURRENT REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3. COMPLIANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. APPROVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
A. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
B. Work Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
FIGURE 1: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
FIGURE 2: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
FIGURE 3: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY
CURRENT (HFEC) INSPECTIONS [Group 1, Configuration 1] . . . . . . . . . . . . . . . 37
FIGURE 4: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY
CURRENT (HFEC) INSPECTIONS [Group 1, Configuration 1] . . . . . . . . . . . . . . . 42
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION [Group 1,
Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION [Group 1,
Configuration 1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
FIGURE 7: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY
CURRENT (HFEC) INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
FIGURE 8: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY
CURRENT (HFEC) INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
3 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 4

Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
4 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT
BLANK PAGE

### Page 5

Commercial 
Airplanes
737
Requirements Bulletin
ALERT
Number: 737-53A1402 RB
Original Issue: July 02, 2021
ATA System: 5311
SUBJECT: FUSELAGE - Frames and Bulkheads - Shimming Non Conformities at STA 727 Frame
Inner Chord and S-18A Web Inspection
THIS DOCUMENT IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN
PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS DOCUMENT
TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS DOCUMENT TO THE
NEW OWNER. THIS IS AN ENHANCED REQUIRED FOR COMPLIANCE DOCUMENT. THE BOEING
PROCESSES USED TO CREATE THE SERVICE BULLETIN (SB) AND THE REQUIREMENTS BULLETIN
(RB) ENSURE THAT THE INFORMATION BETWEEN "RC START" AND "RC END" IN THE SB ARE IDENTICAL
TO THE INFORMATION IN THE SAME SECTIONS (COMPLIANCE, WORK INSTRUCTIONS…) OF THE RB
WHICH THE SB REFERS TO AS THE RELATED DOCUMENT.
1. Effectivity
A. Airplanes
This bulletin is applicable to 737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER
Airplane(s), line number(s) 1-2598, 2600-2721, 2723-2813, 2815-2930, 2932-3068, 3070-3323,
3325-3425, 3427-3521, 3523-3611, 3613-3701, 3703-3791, 3793-3878, 3880-3915, 3917-3968,
3970-4013, 4015-4054, 4056-4098, 4100-4140, 4142-4180, 4182-4218, 4220-4255, 4257-4293,
4295-4330, 4332-4365, 4367-4398, 4400-4444, 4446-4480, 4482-4546, 4548-4608, 4610-4672,
4674-4727, 4729-4767, 4769-4812, 4814-4858, 4860-4897, 4899-4937, 4939-4977, 4979-5019,
5021-5057, 5059-5097, 5099-5137, 5139-5177, 5179-5217, 5219-5261, 5263-5297, 5299-5337,
5339-5367, 5369-5397, 5399-5427, 5429-5457, 5459-5477, 5479-5509, 5511-5541, 5543-5566,
5568-5586, 5588-5601, 5603-5622, 5624-5655, 5657-5667, 5669-5679, 5681-5711, 5713-5727,
5729-5739, 5741-5764, 5766-5787, 5789-5795, 5797-5822, 5824-5850, 5853-5879, 5881-5901,
5904-5935, 5937-5947, 5949-5962, 5964-5991, 5994-6019, 6021-6033, 6035-6047, 6049-6073,
6075, 6077-6103, 6105-6113, 6115-6131, 6133-6153, 6155-6159, 6161-6187, 6190-6215,
6217-6221, 6223-6243, 6245-6249, 6251-6271, 6274-6289, 6291-6299, 6301-6307, 6309-6325,
6327, 6329-6343, 6345-6355, 6357-6359, 6361-6371, 6373-6383, 6386-6395, 6397-6407,
6409-6411, 6413-6419, 6421-6429, 6431-6439, 6442-6447, 6449-6455, 6457-6463, 6465-6467,
6469-6471, 6473-6480, 6482-6489, 6491, 6493-6498, 6500-6507, 6509-6514, 6516-6520,
6522-6527, 6529-6531, 6533-6534, 6536-6541, 6543-6547, 6549-6554, 6556-6559, 6561,
6563-6568, 6570-6574, 6576-6581, 6583-6588, 6590-6593, 6596-6597, 6599-6602, 6604-6606,
6608-6611, 6613-6615, 6617-6620, 6622, 6624, 6626-6629, 6631-6633, 6635-6638, 6640-6642,
6644-6647, 6649-6651, 6653-6656, 6659-6660, 6662-6665, 6667-6671, 6673-6676, 6678-6680,
6682-6685, 6688-6689, 6691-6694, 6696-6698, 6700-6703, 6705-6707, 6709-6712, 6714-6716,
6718-6719, 6721, 6723-6725, 6727-6730, 6732-6734, 6736-6739, 6741-6743, 6745-6748,
6751-6752, 6754-6757, 6759-6761, 6763-6766, 6768-6770, 6772-6775, 6777-6779, 6781-6782,
6786-6788, 6790-6791, 6793, 6795, 6797, 6799-6802, 6804, 6806, 6808-6809, 6811, 6813, 6815,
6817-6818, 6820, 6822-6824, 6826-6827, 6829, 6831-6833, 6835-6836, 6838, 6840, 6842,
6844-6845, 6847, 6849, 6851, 6853-6854, 6856-6858, 6860, 6862-6863, 6865, 6867, 6869-6871,
Export Controlled ECCN: 9E991
Copyright © Unpublished
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Original Issue: July 02, 2021
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### Page 6

6873-6874, 6878-6880, 6882-6883, 6885, 6887-6889, 6891-6892, 6894, 6896, 6898, 6900-6903,
6905, 6907, 6910, 6912-6914, 6916, 6918-6919, 6921, 6923-6925, 6927-6928, 6930, 6932-6934,
6936-6937, 6939, 6943, 6945-6948, 6950, 6952, 6954-6955, 6957-6959, 6961-6962, 6964,
6966-6967, 6969, 6971-6972, 6977, 6979, 6981-6982, 6984, 6986-6987, 6989, 6992, 6994,
6996-6997, 6999, 7001-7002, 7007, 7009, 7011-7012, 7014, 7016-7017, 7019, 7021-7022, 7024,
7026, 7029, 7031-7032, 7034, 7036-7037, 7039, 7041, 7046-7047, 7049, 7051-7052, 7054,
7056-7057, 7059, 7061, 7063, 7066-7067, 7069, 7071-7072, 7076, 7078, 7081-7082, 7084,
7086-7087, 7089, 7091-7092, 7094, 7097, 7099, 7101-7102, 7104, 7106-7107, 7109, 7112,
7116-7117, 7119, 7121-7122, 7124, 7126-7127, 7129, 7131, 7134, 7136-7137, 7139, 7141-7142,
7146, 7149, 7151-7152, 7154, 7156-7157, 7159, 7161-7162, 7164, 7167, 7169, 7171-7172, 7174,
7176-7177, 7179, 7182, 7187, 7189, 7191, 7194, 7197, 7199, 7202, 7204, 7206, 7209, 7212,
7214, 7217, 7221, 7224, 7227, 7229, 7232, 7234-7235, 7239, 7242, 7244, 7247, 7249, 7251,
7257, 7259, 7262, 7264, 7266, 7269, 7272, 7274, 7277, 7279-7280, 7284, 7287, 7292, 7294,
7297, 7299, 7302, 7304, 7307, 7309, 7312, 7314, 7317, 7319, 7322, 7327, 7329, 7332, 7334,
7337, 7339, 7342, 7344, 7347, 7349, 7352, 7354, 7357, 7362, 7364, 7367, 7369, 7372, 7374,
7377, 7379, 7382, 7387, 7397, 7402, 7407, 7412, 7417, 7422, 7432, 7437, 7442, 7447, 7452,
7457, 7467, 7472, 7477, 7482, 7487, 7492, 7502, 7507, 7512, 7517, 7522, 7527, 7537, 7547,
7552, 7557, 7562, 7572, 7577, 7582, 7587, 7592, 7597, 8592 in 1 Group(s). Where the effectivity
is presented with hyphens between line numbers, the airplane applicability means "through" and
"inclusive", e.g. line numbers 1-9 means line numbers 1 through 9 inclusive.
DESCRIPTIONCONFIGURATIONGROUP
737-600/-700/-700C/-800/-900/-900ER Airplanes.-1
737-600/-700/-700C/-800/-900/-900ER: Airplanes that were not in
the effectivity of Requirements Bulletin 737-53A1385 RB or airplanes
that have not installed a shim in accordance with Requirements
Bulletin 737-53A1385 RB.
1
737-600/-700/-700C/-800/-900/-900ER Airplanes that have a new
shim installed in accordance with Requirements Bulletin 737-53A1385
RB.
2
Airplane Models:
737-600, 737-700, 737-700C, 737-800, 737-900, 737-900ER
GroupVariable Number
1YA001 - YA099
1YA101 - YA199
1YA201 - YA211
1YA221
1YA231 - YA242
1YA251 - YA256
1YA271 - YA272
GroupVariable Number
1YA291
1YA301 - YA302
1YA311 - YA314
1YA321 - YA323
1YA336 - YA345
1YA351
1YA356 - YA357
GroupVariable Number
1YA366 - YA367
1YA371 - YA377
1YA501 - YA536
1YA541 - YA552
1YA571 - YA578
1YA601 - YA615
1YA621 - YA622
Export Controlled ECCN: 9E991
Copyright © Unpublished
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Original Issue: July 02, 2021
737-53A1402 RB
6 of 64
REQUIREMENTS BULLETIN 737-53A1402
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### Page 7

GroupVariable Number
1YA626 - YA631
1YA635 - YA636
1YA641 - YA642
1YA645 - YA650
1YA656 - YA659
1YA666 - YA667
1YA671 - YA672
1YA681 - YA691
1YA701 - YA710
1YA721 - YA722
1YA731 - YA734
1YA751 - YA756
1YA801 - YA803
1YA809
1YA811 - YA814
1YA831 - YA835
1YA841 - YA862
1YA881 - YA882
1YA891 - YA892
1YA961 - YA978
1YB001 - YB006
1YB101 - YB132
1YB151 - YB153
1YB156 - YB158
1YB161 - YB164
1YB171 - YB172
1YB181 - YB184
1YB201 - YB208
1YB271
1YB276
1YB301 - YB310
1YB371 - YB392
1YB501 - YB502
GroupVariable Number
1YB521 - YB526
1YB541 - YB544
1YB551
1YB561 - YB598
1YB601 - YB636
1YB651
1YB656
1YB671 - YB672
1YB851 - YB863
1YB871 - YB874
1YB881 - YB893
1YB901 - YB903
1YB911
1YB961 - YB975
1YB981
1YB986 - YB998
1YC001 - YC030
1YC051 - YC084
1YC091 - YC095
1YC101 - YC104
1YC111 - YC113
1YC121
1YC126 - YC127
1YC136 - YC141
1YC146 - YC147
1YC151 - YC156
1YC166 - YC171
1YC176 - YC179
1YC186 - YC190
1YC201 - YC203
1YC206 - YC207
1YC301 - YC305
1YC321 - YC387
GroupVariable Number
1YC391 - YC394
1YC396
1YC401 - YC417
1YC421 - YC422
1YC426 - YC428
1YC436 - YC439
1YC441 - YC448
1YC451 - YC455
1YC459
1YC461 - YC467
1YC471 - YC499
1YC501 - YC526
1YC571 - YC583
1YC587 - YC589
1YC591 - YC593
1YC601 - YC655
1YC681 - YC696
1YC701 - YC715
1YC720 - YC725
1YC727 - YC752
1YC761 - YC770
1YC781 - YC793
1YC801 - YC892
1YC901 - YC907
1YC921 - YC922
1YC931 - YC932
1YC941 - YC951
1YC971 - YC978
1YC981 - YC983
1YD001 - YD007
1YD021 - YD025
1YD041 - YD057
1YD081 - YD084
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
7 of 64
REQUIREMENTS BULLETIN 737-53A1402
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### Page 8

GroupVariable Number
1YD101 - YD117
1YD121 - YD126
1YD151 - YD159
1YD171 - YD172
1YD201 - YD203
1YD206 - YD209
1YD216 - YD219
1YD251 - YD254
1YD256 - YD257
1YD261
1YD301 - YD334
1YD391
1YD401 - YD410
1YD412 - YD424
1YD481 - YD485
1YD491 - YD499
1YD501 - YD512
1YD531 - YD535
1YD541 - YD547
1YD561 - YD564
1YD571 - YD572
1YD591 - YD595
1YD601 - YD612
1YD651 - YD655
1YE001 - YE020
1YE051
1YE101 - YE109
1YE151 - YE157
1YE171 - YE172
1YE201 - YE206
1YE301 - YE305
1YE321 - YE326
1YE371 - YE383
GroupVariable Number
1YF001 - YF011
1YF021 - YF049
1YF051 - YF080
1YF086 - YF087
1YF106 - YF107
1YF111 - YF114
1YF116 - YF119
1YF121 - YF132
1YF176 - YF178
1YF191 - YF192
1YF201 - YF276
1YF401 - YF402
1YF431 - YF432
1YF436 - YF437
1YF441 - YF442
1YF451 - YF460
1YF501 - YF599
1YF601 - YF685
1YF691 - YF695
1YF701 - YF707
1YF801 - YF805
1YF831 - YF832
1YF836 - YF838
1YF871 - YF872
1YF901 - YF905
1YF921 - YF928
1YF951 - YF954
1YG001 - YG044
1YG061 - YG064
1YG066 - YG089
1YG091 - YG099
1YG101 - YG104
1YG111 - YG114
GroupVariable Number
1YG116 - YG148
1YG201 - YG205
1YG211 - YG214
1YG221 - YG224
1YG251 - YG252
1YG501 - YG517
1YG601 - YG602
1YG701
1YG711
1YG721 - YG722
1YH001 - YH012
1YH031 - YH055
1YH071 - YH080
1YH101 - YH132
1YH201 - YH202
1YH206 - YH207
1YH301 - YH307
1YH321 - YH322
1YH501 - YH542
1YH551 - YH594
1YH601 - YH606
1YH611 - YH620
1YH631 - YH632
1YH636 - YH637
1YH641
1YH681 - YH686
1YH701 - YH755
1YH801 - YH899
1YH901 - YH908
1YH911 - YH915
1YH951 - YH952
1YJ001 - YJ013
1YJ021
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 9

GroupVariable Number
1YJ471 - YJ480
1YJ501 - YJ517
1YJ531 - YJ579
1YJ591 - YJ599
1YJ631 - YJ632
1YJ671 - YJ694
1YJ801 - YJ867
1YJ871 - YJ880
1YJ901 - YJ904
1YJ908 - YJ929
1YJ931 - YJ937
1YJ941 - YJ956
1YJ961
1YJ976 - YJ977
1YK001 - YK007
1YK101 - YK104
1YK111 - YK112
1YK121 - YK122
1YK131 - YK133
1YK136 - YK139
1YK141 - YK142
1YK146 - YK148
1YK151 - YK154
1YK161 - YK167
1YK171
1YK176 - YK177
1YK186
1YK191
1YK196
1YK201 - YK202
1YK301 - YK314
1YK321 - YK340
1YK361 - YK378
GroupVariable Number
1YK401 - YK406
1YK426 - YK427
1YK431 - YK450
1YK456 - YK467
1YK471 - YK473
1YK476
1YK478
1YK480 - YK487
1YK491 - YK493
1YK495 - YK499
1YK511 - YK516
1YK521 - YK530
1YK551 - YK571
1YK576 - YK577
1YK580 - YK585
1YK601 - YK602
1YK606 - YK607
1YK611 - YK616
1YK621 - YK634
1YK641 - YK644
1YK651 - YK665
1YK671 - YK672
1YK676 - YK677
1YK681 - YK686
1YK691
1YK695 - YK699
1YK701 - YK713
1YK716 - YK719
1YK721 - YK741
1YK751 - YK770
1YK776 - YK778
1YK781 - YK785
1YK791 - YK792
GroupVariable Number
1YK796 - YK797
1YK801 - YK899
1YK901 - YK912
1YK918 - YK919
1YK921 - YK929
1YK941 - YK999
1YL001 - YL005
1YL011 - YL016
1YL021 - YL024
1YL051 - YL052
1YL056 - YL057
1YL061
1YL066 - YL069
1YL076 - YL077
1YL101 - YL137
1YL201 - YL237
1YL241 - YL242
1YL271 - YL272
1YL281 - YL284
1YL301 - YL303
1YL311 - YL314
1YL316 - YL321
1YL351 - YL353
1YL371 - YL374
1YL401
1YL421 - YL429
1YL431 - YL444
1YL461 - YL478
1YL501 - YL509
1YL531 - YL534
1YL541 - YL551
1YL561 - YL579
1YL591 - YL598
Export Controlled ECCN: 9E991
Copyright © Unpublished
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Original Issue: July 02, 2021
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REQUIREMENTS BULLETIN 737-53A1402
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### Page 10

GroupVariable Number
1YL601 - YL606
1YL611 - YL612
1YL616 - YL617
1YL621
1YL626
1YL631 - YL634
1YL636 - YL637
1YL661 - YL664
1YL676 - YL691
1YL696 - YL697
1YL701 - YL707
1YL731
1YL751 - YL752
1YL756 - YL757
1YL761 - YL780
1YL796 - YL797
1YL801 - YL815
1YL901 - YL910
1YL921 - YL940
1YL951 - YL968
1YM101 - YM103
1YM201 - YM244
1YM251 - YM299
1YM301 - YM399
1YM401 - YM415
1YM471
1YM481 - YM484
1YM501 - YM515
1YM521 - YM522
1YM541
1YM551 - YM553
1YM571 - YM572
1YM581 - YM582
GroupVariable Number
1YM591 - YM599
1YM631 - YM634
1YM641 - YM652
1YM671 - YM674
1YM691 - YM699
1YM701 - YM710
1YM761 - YM765
1YM771 - YM779
1YN001 - YN016
1YN021 - YN024
1YN061
1YN071 - YN082
1YN091 - YN092
1YN101 - YN112
1YN121
1YN126
1YN201 - YN202
1YN211 - YN219
1YN231 - YN236
1YN261
1YN501
1YN531 - YN534
1YN551 - YN566
1YN581 - YN585
1YN591 - YN593
1YN601 - YN606
1YN651 - YN653
1YN661 - YN663
1YN666 - YN667
1YN671 - YN674
1YN701 - YN702
1YN741 - YN746
1YN756 - YN758
GroupVariable Number
1YQ001 - YQ003
1YQ011 - YQ021
1YQ026 - YQ029
1YQ036 - YQ045
1YQ201 - YQ207
1YQ231
1YQ241 - YQ251
1YQ281 - YQ284
1YQ291 - YQ296
1YQ301 - YQ302
1YQ321 - YQ324
1YQ331 - YQ334
1YQ346 - YQ347
1YQ351 - YQ367
1YQ371
1YQ401 - YQ403
1YQ451 - YQ454
1YQ456
1YQ461
1YQ471
1YQ501 - YQ520
1YQ601 - YQ606
1YQ610 - YQ614
1YR001 - YR098
1YR101 - YR105
1YR111 - YR124
1YR126 - YR144
1YR166 - YR182
1YR186 - YR198
1YR201 - YR215
1YR231 - YR294
1YR296 - YR297
1YR301 - YR334
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### Page 11

GroupVariable Number
1YR338 - YR341
1YR361 - YR366
1YR371 - YR373
1YR376 - YR377
1YR381 - YR382
1YR386 - YR388
1YR391
1YR396 - YR399
1YR401 - YR405
1YR411 - YR413
1YR416 - YR418
1YR421 - YR424
1YR426 - YR455
1YR457 - YR499
1YR501 - YR506
1YR511 - YR520
1YR526 - YR544
1YR546 - YR551
1YR556 - YR562
1YR571 - YR582
1YR591 - YR592
1YR601 - YR605
1YR616 - YR658
1YR661 - YR663
1YR671 - YR673
1YR676 - YR678
1YR681 - YR682
1YR701 - YR769
1YR771 - YR799
1YR801 - YR827
1YR831 - YR838
1YR841 - YR899
1YR901 - YR903
GroupVariable Number
1YR931 - YR934
1YR938 - YR944
1YR951 - YR998
1YS001 - YS002
1YS006 - YS009
1YS031 - YS032
1YS051 - YS073
1YS101 - YS120
1YS126 - YS142
1YS146 - YS160
1YS166 - YS194
1YS196 - YS197
1YS201 - YS209
1YS221 - YS225
1YS231 - YS236
1YS271 - YS288
1YS295 - YS296
1YS301 - YS348
1YS351 - YS378
1YS381 - YS386
1YS393 - YS395
1YS401
1YS451
1YS456 - YS457
1YS462 - YS465
1YS467
1YS501 - YS502
1YS506
1YS511 - YS518
1YS531
1YS536 - YS538
1YS541 - YS542
1YS546
GroupVariable Number
1YS551 - YS556
1YS561 - YS578
1YS581 - YS595
1YS601 - YS690
1YS701 - YS716
1YS721 - YS762
1YS771 - YS780
1YS806 - YS810
1YS816 - YS818
1YS823 - YS825
1YS851 - YS863
1YS876
1YS881 - YS884
1YS891 - YS894
1YS896 - YS897
1YS901 - YS909
1YS911 - YS957
1YS961 - YS974
1YS976 - YS977
1YS981 - YS987
1YS991 - YS998
1YT001 - YT004
1YT006
1YT026 - YT027
1YT031 - YT032
1YT036 - YT038
1YT061 - YT068
1YT101 - YT138
1YT176 - YT185
1YT191
1YT196 - YT199
1YT201
1YT206 - YT207
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### Page 12

GroupVariable Number
1YT211 - YT213
1YT251 - YT299
1YT301 - YT307
1YT311 - YT312
1YT321 - YT355
1YT371 - YT372
1YT381
1YT391 - YT396
1YT401 - YT403
1YT411 - YT417
1YT427
1YT461 - YT477
1YT491 - YT492
1YT501 - YT521
1YT551 - YT552
1YT556 - YT563
1YT565
1YT571 - YT578
1YT601 - YT606
1YT701 - YT708
1YT723 - YT726
1YT761 - YT781
1YT791 - YT794
1YT796 - YT797
1YT801 - YT804
1YT811 - YT813
1YT826 - YT827
1YT831 - YT832
1YT841 - YT852
1YT856 - YT863
1YT885 - YT887
1YT891 - YT895
1YT901 - YT998
GroupVariable Number
1YU001 - YU060
1YU201 - YU218
1YU301 - YU329
1YU901 - YU931
1YV001 - YV012
1YV021 - YV023
1YV030 - YV034
1YV037 - YV042
1YV045 - YV047
1YV051 - YV059
1YV081
1YV083 - YV084
1YV097 - YV099
1YV101 - YV154
1YV201 - YV203
1YV251 - YV252
1YV256 - YV257
1YV301 - YV312
1YV351 - YV368
1YV381 - YV388
1YV391 - YV394
1YV401
1YV411 - YV413
1YV431 - YV433
1YV441 - YV454
1YV461 - YV464
1YV467 - YV470
1YV501 - YV512
1YV521
1YV571 - YV586
1YV596
1YV601 - YV605
1YV651 - YV674
GroupVariable Number
1YV676
1YV695 - YV696
1YV701 - YV702
1YV711
1YV722 - YV731
1YV741 - YV794
1YV801 - YV820
1YV831 - YV848
1YV881 - YV883
1YV901 - YV915
1YV923 - YV926
1YV971 - YV983
1YW001
1YW011 - YW099
1YW101 - YW164
1YW201 - YW212
1YW226 - YW240
1YW245 - YW261
1YW263
1YW267 - YW281
1YW283 - YW285
1YW292 - YW299
1YW351
1YW356 - YW358
1YW361 - YW366
1YW371 - YW399
1YW401 - YW430
1YW441 - YW445
1YW451 - YW452
1YW471 - YW472
1YW491 - YW498
1YW531 - YW536
1YW541 - YW545
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### Page 13

GroupVariable Number
1YW551 - YW580
1YW585 - YW591
1YW595 - YW596
1YW601
1YW610 - YW613
1YW616 - YW623
1YW666
GroupVariable Number
1YW696 - YW699
1YW701 - YW715
1YW726 - YW731
1YW766 - YW775
1YW801 - YW803
1YW811 - YW813
1YW821
GroupVariable Number
1YW831
1YW881
1YW891 - YW893
1YW906 - YW910
1YW916 - YW918
1YW921 - YW925
1YW971 - YW976
B. Spares Affected
None.
2. CONCURRENT REQUIREMENTS
None.
3. COMPLIANCE
The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to
Requirements Bulletin 737-53A1402 RB. The Airworthiness Directive will make the compliance tasks and
times given in Requirements Bulletin 737-53A1402 RB mandatory.
For airplanes which have incorporated Boeing Business Jet (BBJ) Lower Cabin Altitude Supplemental Type
Certificate (STC) ST01697SE (6500 feet maximum cabin altitude in lieu of 8000 feet) as referenced in
Boeing SB 737-21-1149, the flight cycle related compliance times are different from those specified in this
service bulletin. All initial compliance times (thresholds) specified in flight cycles must be reduced to half of
those specified in this service bulletin. All repeat interval compliance times specified in flight cycles must
be reduced to one-quarter of those specified in this Requirements Bulletin.
Accomplish the required action(s), based on the applicable condition(s) in Table(s) 1 through 4, in accordance
with Accomplishment Instructions.
When more than one OPTION is given for a CONDITION, do only one of the OPTION numbers. When
more than one ACTION is given for a CONDITION or an OPTION, do all of the ACTION numbers for that
CONDITION or OPTION.
Group 1, Configuration 1:
Table 1: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
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### Page 14

Group 1, Configuration 1:
Table 1: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 1:
ANY REPAIR FOUND
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
Do an open hole High Frequen-
cy Eddy Current (HFEC) inspec-
tion of the entire stackup of the
STA 727 frame inner chord at
S-18A and surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack.
CONDITION 2:
NO REPAIR FOUND
-Before further flight.Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 2.1:
ANY CRACK FOUND
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
CONDITION 2.2 (ACTION 1):
Do the shim installation between
the STA 727 frame inner chord
and S-18A.
CONDITION 2.2:
NO CRACK FOUND
-Within 30,000 flight cycles after the
shim installation.
CONDITION 2.2 (ACTION 2):
Do a surface HFEC inspection
of the STA 727 frame inner
chord at S-18A for any crack.
(b)
-Before further flight.Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 2.2.1:
ANY CRACK FOUND
30,000 flight
cycles.
-Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 2.2.2:
NO CRACK FOUND
(a) CONDITION 1 ACTION is not required for the repairs or the preventive modifications that were accomplished
in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDITION 2
and do all applicable on-condition action(s).
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### Page 15

Group 1, Configuration 1:
Table 1: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
Group 1, Configuration 1:
Table 2: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 3:
ANY REPAIR FOUND
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
Do an open hole High Frequen-
cy Eddy Current (HFEC) inspec-
tion of the entire stackup of the
STA 727 frame inner chord at
S-18A and surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack.
CONDITION 4:
NO REPAIR FOUND
-Before further flight.Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 4.1:
ANY CRACK FOUND
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### Page 16

Group 1, Configuration 1:
Table 2: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time (Whichever
Occurs Later)
ActionCondition
-Within 6,000 flight
cycles after the
Original Issue date
of the Require-
ments Bulletin
737-53A1402 RB.
Before 22,500
total flight cy-
cles.
CONDITION 4.2 (ACTION 1):
Do the shim installation between
the STA 727 frame inner chord
and S-18A.
CONDITION 4.2:
NO CRACK FOUND
-Within 30,000 flight cycles after the
shim installation.
CONDITION 4.2 (ACTION 2):
Do a surface HFEC inspection
of the STA 727 frame inner
chord at S-18A for any crack.
(b)
-Before further flight.Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 4.2.1:
ANY CRACK FOUND
30,000 flight
cycles.
-Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 4.2.2:
NO CRACK FOUND
(a) CONDITION 3 ACTION is not required for the repairs or the preventive modifications that were accomplished
in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDITION 4
and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
Group 1, Configuration 2:
Table 3: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time
ActionCondition
-Within 30,000 flight cycles after
the shim installation in accor-
dance with Requirements Bul-
letin 737-53A1385 R00.
Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
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### Page 17

Group 1, Configuration 2:
Table 3: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time
ActionCondition
-Within 30,000 flight cycles after
the shim installation in accor-
dance with Requirements Bul-
letin 737-53A1385 R00 RB.
Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 5:
ANY REPAIR FOUND
-Within 30,000 flight cycles after
the shim installation in accor-
dance with Requirements Bul-
letin 737-53A1385 R00 RB.
Do a surface High Frequency
Eddy Current (HFEC) inspection
of the STA 727 frame inner
chord at S-18A for any crack.
CONDITION 6:
NO REPAIR FOUND
-Before further flight.Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 6.1:
ANY CRACK FOUND
30,000 flight
cycles.
-Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 6.2:
NO CRACK FOUND
(a) CONDITION 5 ACTION is not required for the repairs or the preventive modifications that were accom-
plished in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDI-
TION 6 and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
Group 1, Configuration 2:
Table 4: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time
ActionCondition
-Within 30,000 flight cycles after
the shim installation in accor-
dance with Requirements Bul-
letin 737-53A1385 R00 RB.
Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
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ALERTALERT

### Page 18

Group 1, Configuration 2:
Table 4: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Repeat Inter-
val (Not to Ex-
ceed)
Boeing Recommended
Compliance Time
ActionCondition
-Within 30,000 flight cycles after
the shim installation in accor-
dance with Requirements Bul-
letin 737-53A1385 R00 RB.
Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 7:
ANY REPAIR FOUND
-Within 30,000 flight cycles after
the shim installation in accor-
dance with Requirements Bul-
letin 737-53A1385 R00 RB.
Do a surface High Frequency
Eddy Current (HFEC) inspection
of the STA 727 frame inner
chord at S-18A for any crack.
CONDITION 8:
NO REPAIR FOUND
-Before further flight.Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 8.1:
ANY CRACK FOUND
30,000 flight
cycles.
-Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 8.2:
NO CRACK FOUND
(a) CONDITION 7 ACTION is not required for the repairs or the preventive modifications that were accom-
plished in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDI-
TION 8 and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
4. APPROVAL
This Requirements Bulletin was examined by the Federal Aviation Administration (FAA). The changes
specified in this document comply with the applicable regulations and are FAA approved, as well as European
Union Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved
airplanes listed in this Requirements Bulletin effectivity. This document and its approval were based on the
airplane in its original Boeing delivery configuration or as modified by other Boeing changes.
This Requirements Bulletin is also approved for airplanes converted into 737-800BCF under project number
TS14-0042 that have incorporated Boeing drawing 800A0003 specified in Type Certificate Data Sheet
(TCDS).
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### Page 19

This Requirements Bulletin is also approved for airplanes having FAA Aviation Partners Boeing (APB)
Supplemental Type Certificate (STC) number ST00830SE installed (not including any areas affected by
the split scimitar winglet configuration).
For 737-700C and BBJ models that have APB winglets installed by STC number ST00830SE, the operator
is responsible for obtaining appropriate regulatory agency approval before incorporating this Requirements
Bulletin if the bulletin is in the area affected by blended winglets.
If an airplane has a non-Boeing modification or repair that affects a component or system also affected by
this Requirements Bulletin, the operator is responsible for obtaining appropriate regulatory agency approval
before incorporating this Requirements Bulletin.
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### Page 20

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BLANK PAGE

### Page 21

5.    ACCOMPLISHMENT INSTRUCTIONS
A. GENERAL INFORMATION
NOTE: 1. This is an Enhanced Required for Compliance document. There will be a separate
Service Bulletin (SB) and a separate Requirements Bulletin (RB). If an RB is mandated
by an Airworthiness Directive (AD), then all applicable requirements specified in the
RB must be done. For the related SB, some locations are marked RC Start and RC
End to identify the requirements that are restated from the RB. For the related SB,
the areas between RC Start and RC End, including sub-steps and any figures
identified between RC Start and RC End, must be done to comply with the AD.
Therefore, an Alternative Method of Compliance (AMOC) is required for any deviations
to steps between RC Start and RC End, including substeps and identified figures.
For the related SB, the steps not between RC Start and RC End may be deviated
from using accepted methods in accordance with the operator's maintenance or
inspection program without obtaining approval of an AMOC; this is provided that the
steps between RC Start and RC End, including sub-steps and identified figures, can
still be done as specified, and the airplane can be put back in an airworthy condition.
Figures not required for compliance are omitted from the RB.
2. This is an Enhanced Required for Compliance document. The Boeing processes
used to create the Service Bulletin (SB) and the Requirements Bulletin (RB) ensure
that the information between "RC Start" and "RC End" in the SB are identical to the
information in the same sections (Compliance, Work Instructions...) of the RB which
the SB refers to as the related document.
3. The compliance times for the actions in WORK INSTRUCTIONS are in Compliance.
4. Boeing Service Letter 737-SL-51-042, Damage Reporting and Repair Plan/Design
Guidelines, is an acceptable procedure to request information from Boeing for
additional structural repair instructions. The Service Letter describes what information
must be provided to Boeing before a structural repair can be provided.
5. Unless shown differently, these dimensions and tolerances are used:
– Linear dimensions are in inches
– Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus
or minus 0.03 inch
– Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch
– Angular tolerance is plus or minus 2 degrees
– Hole dimensions for standard solid rivets and fasteners are in Structural Repair
Manual (SRM) Chapter 51
– Torque Values:
— Values for structural fasteners are given in 737 Structural Repair Manual,
Chapter 51.
— Values for airframe maintenance tasks are included in Chapter 20 of 737
Aircraft Maintenance Manual (AMM).
— Values for electrical maintenance tasks are included in Chapter 20 of
Standard Wiring Practices Manual (SWPM).
— Values for engine maintenance tasks are included in Chapter 70 of 737
Aircraft Maintenance Manual (AMM).
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### Page 22

— Non-standard torque values for maintenance tasks are included in the
applicable installation step.
6. These work instructions refer to procedures included in other Boeing documents.
When the words "refer to" are used and the operator has an accepted alternative
procedure, the accepted alternative procedure can be used. When the words "in
accordance with" are included in the instruction, the procedure in the Boeing document
must be used.
7. If it is necessary to remove more parts for access, you can remove those parts. If
you can get access without removing identified parts, it is not necessary to remove
all of the identified parts. Jacking and shoring limitations must be observed.
8. Use the approved fastener, process and material substitutions in accordance with
SRM Chapter 51.
9. A Detailed Inspection is defined as: An intensive examination of a specific item,
installation or assembly to detect damage, failure or irregularity. This could include
tactile assessment in which a component or assembly can be checked for
tightness/security. Available lighting is normally supplemented with a direct source
of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors
and magnifying lenses may be necessary. Surface cleaning and elaborate access
procedures may be required.
10. A General Visual Inspection is defined as: A visual examination of an interior or
exterior area, installation or assembly to detect obvious damage, failure or irregularity.
This level of inspection is made from within touching distance, unless otherwise
specified. A mirror may be necessary to enhance visual access to all exposed surfaces
in the inspection area. This level of inspection is made under normally available
lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may
require removal or opening of access panels or doors. Stands, ladders or platforms
may be required to gain proximity to the area being checked. Basic cleaning may be
required to ensure appropriate visibility.
11. When more than one OPTION is given for a CONDITION, do only one of the OPTION
numbers. When more than one ACTION is given for a CONDITION or an OPTION,
do all of the ACTION numbers for that CONDITION or OPTION.
12. If the length of any fastener specified in this service bulletin does not meet installation
standards given in SRM Chapter 51, then a fastener of the same specification, or
an approved substitute, with a length which meets the installation standards given
in SRM Chapter 51 may be used. In addition, washers may be installed for fastener
grip length in accordance with SRM Chapter 51. Refer to SOPM 20-50-01 for alternate
full threaded fasteners (screws) needed for installation in this service bulletin.
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 23

B. WORK INSTRUCTIONS
Actions Required For Compliance
1. Requirements
Group 1, Configuration 1:
Table 1: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 1: OPEN AC-
CESS
-Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
-FIGURE 1
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 1:
ANY REPAIR FOUND
-FIGURE 3Do an open hole High Frequen-
cy Eddy Current (HFEC) inspec-
tion of the entire stackup of the
STA 727 frame inner chord at
S-18A and surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack.
CONDITION 2:
NO REPAIR FOUND
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 2.1:
ANY CRACK FOUND
-FIGURE 5CONDITION 2.2 (ACTION 1):CONDITION 2.2:
NO CRACK FOUND Do the shim installation between
the STA 727 frame inner chord
and S-18A.
PART 2: CLOSE
ACCESS
-
PART 1: OPEN AC-
CESS
-CONDITION 2.2 (ACTION 2):
Do a surface HFEC inspection
of the STA 727 frame inner
chord at S-18A for any crack.
(b)
-FIGURE 7
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### Page 24

Group 1, Configuration 1:
Table 1: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 2.2.1:
ANY CRACK FOUND
PART 1: OPEN AC-
CESS
-Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 2.2.2:
NO CRACK FOUND
-FIGURE 7
PART 2: CLOSE
ACCESS
-
(a) CONDITION 1 ACTION is not required for the repairs or the preventive modifications that were accom-
plished in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDI-
TION 2 and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
Group 1, Configuration 1:
Table 2: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 1: OPEN AC-
CESS
-Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
-FIGURE 2
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### Page 25

Group 1, Configuration 1:
Table 2: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 3:
ANY REPAIR FOUND
FIGURE 4Do an open hole High Frequen-
cy Eddy Current (HFEC) inspec-
tion of the entire stackup of the
STA 727 frame inner chord at
S-18A and surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack.
CONDITION 4:
NO REPAIR FOUND
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 4.1:
ANY CRACK FOUND
-FIGURE 6CONDITION 4.2 (ACTION 1):CONDITION 4.2:
NO CRACK FOUND Do the shim installation between
the STA 727 frame inner chord
and S-18A.
PART 2: CLOSE
ACCESS
-
PART 1: OPEN AC-
CESS
-CONDITION 4.2 (ACTION 2):
Do a surface HFEC inspection
of the STA 727 frame inner
chord at S-18A for any crack.
(b)
-FIGURE 8
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 4.2.1:
ANY CRACK FOUND
PART 1: OPEN AC-
CESS
-Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 4.2.2:
NO CRACK FOUND
-FIGURE 8
PART 2: CLOSE
ACCESS
-
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### Page 26

Group 1, Configuration 1:
Table 2: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
(a) CONDITION 3 ACTION is not required for the repairs or the preventive modifications that were accom-
plished in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDI-
TION 4 and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
Group 1, Configuration 2:
Table 3: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 1: OPEN AC-
CESS
-Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
-FIGURE 1
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 5:
ANY REPAIR FOUND
-FIGURE 7Do a surface High Frequency
Eddy Current (HFEC) inspection
of the STA 727 frame inner
chord at S-18A for any crack.
CONDITION 6:
NO REPAIR FOUND
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### Page 27

Group 1, Configuration 2:
Table 3: Inspection of the STA 727 Frame Inner Chord at S-18A, Left Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 6.1:
ANY CRACK FOUND
-FIGURE 7Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 6.2:
NO CRACK FOUND PART 2: CLOSE
ACCESS
-
(a) CONDITION 5 ACTION is not required for the repairs or the preventive modifications that were accom-
plished in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDI-
TION 6 and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
Group 1, Configuration 2:
Table 4: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 1: OPEN AC-
CESS
-Do a General Visual Inspection
of STA 727 frame inner chord
at S-18A for any repair.
All Airplanes
-FIGURE 2
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ALERTALERT

### Page 28

Group 1, Configuration 2:
Table 4: Inspection of the STA 727 Frame Inner Chord at S-18A, Right Side
Refer to the listed
procedures in SB
737-53A1402 Origi-
nal Issue or later
approved revi-
sions as an accept-
ed procedure.
Method of ComplianceActionCondition
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for alternative inspection(s) in-
structions to Requirements Bul-
letin 737-53A1402 RB, do the
alternative inspection(s), and do
all applicable on-condition ac-
tion(s). (a)
CONDITION 7:
ANY REPAIR FOUND
FIGURE 8Do a surface High Frequency
Eddy Current (HFEC) inspection
of the STA 727 frame inner
chord at S-18A for any crack.
CONDITION 8:
NO REPAIR FOUND
PART 2: CLOSE
ACCESS
-Contact The Boeing Company
for repair instructions and do the
repair.
CONDITION 8.1:
ANY CRACK FOUND
-FIGURE 8Repeat the surface HFEC in-
spection of the STA 727 frame
inner chord at S-18A for any
crack. (b)
CONDITION 8.2:
NO CRACK FOUND PART 2: CLOSE
ACCESS
-
(a) CONDITION 7 ACTION is not required for the repairs or the preventive modifications that were accom-
plished in accordance with Service Bulletin 737-53A1325 R00 or R01. Continue with action from CONDI-
TION 8 and do all applicable on-condition action(s).
(b) It is not required to do the HFEC inspections of the STA 727 frame inner chord at S-18A in areas where
a repair covers the affected inspection zone provided:
1. The repair is the corrective action to the crack condition identified in Requirements Bulletin 737-
53A1402 RB or 737-53A1385 RB and installed after the Original Issue date of Requirements
Bulletin 737-53A1402 RB or 737-53A1385 RB, AND
2. The installed repair was approved by the Boeing Company Organization Designation Authorization
(ODA) via a FAA Form 8100-9.
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 29 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727
S-18A
2960909
FIGURE 1: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 1 OF 4)
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### Page 30 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
FRAME
S-18A
S-18A
WEB
2960910
FIGURE 1: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 2 OF 4)
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### Page 31 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
AFT UPPER FITTING
S-18A
WEB
GENERAL VISUAL  INSPECTION AREA  2960911
FIGURE 1: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 3 OF 4)
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### Page 32

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1--Inspect1
(a) Do a General Visual Inspection for any repair in the area of STA 727 frame inner chord, S-18A web and
aft upper fitting.
FIGURE 1: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 4 OF 4)
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 33 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727
S-18A
2960912
FIGURE 2: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 1 OF 4)
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### Page 34 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727
INNER CHORD
FRAME
-__
S-18A
2960913
FIGURE 2: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 2 OF 4)
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### Page 35 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT
INNER CHORD
AFT UPPER FITTING
S-18A
WEB
• GENERAL VISUAL
INSPECTION AREA
2960915
FIGURE 2: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 3 OF 4)
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### Page 36

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1--Inspect1
(a) Do a General Visual Inspection for any repair in the area of STA 727 frame inner chord, S-18A web and
aft upper fitting.
FIGURE 2: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - GENERAL VISUAL INSPECTION
(SHEET 4 OF 4)
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 37 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
This Figure applies only to: Group 1, Configuration 1.
STA
727
STA
727
S-18A
2960916
FIGURE 3: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 1 OF 5)
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### Page 38 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
FRAME
S-18A
S-18A
WEB
TEWD
2960917
FIGURE 3: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 2 OF 5)
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### Page 39 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
AFT UPPER FITTING
SHIM 2
BOLT 2
MINIMUM 2 INCHES
(2 LOCATIONS)
S-18A
WEB
INSPECTION AREA  HFEC SURFACE  2960918
FIGURE 3: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 3 OF 5)
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### Page 40 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
S-18A
WEB
•
-INNER CHORD
FWD
A-A
* OPEN HOLE HFEC
INSPECTION AREA
2961124
FIGURE 3: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 4 OF 5)
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### Page 41

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)2BACB30NX8KBOLTRemove1
(a)2BACN11E4NUTRemove
(b)-BACB30NX8KBOLTRemove2
(b)-BACC30BH8COLLARRemove
(c)(d)1-SHIMRemove
(e)2-FASTENER HOLEInspect3
(f)1144A2619-()INNER CHORDInspect4
(a) Remove and discard existing bolts and nuts from the structure. Refer to 737-600 SRM 51-40-02, 737-700
SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM 51-40-02, 737-800 SRM 51-40-
02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER SRM 51-40-02 as an accepted
procedure.
(b) It is acceptable to remove up to four fasteners and collars to get the access to remove the shim. Refer to
737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM
51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER
SRM 51-40-02 as an accepted procedure.
(c) If an existing shim is present, remove and discard the shim. Use non-metallic tools to remove existing
sealant at the mating surfaces from shimming. Refer to SOPM 20-50-19 for a list of acceptable sealant
removal tools.
(d) Clean the faying surface of the affected parts. Refer to SOPM 20-30-03 for general cleaning procedures.
(e) Do an open hole High Frequency Eddy Current (HFEC) inspection of the fastener holes in all parts in the
stackup for any crack in accordance with 737 NDT Manual Part 6, 51-00-00 Procedure 16.
(f) Do a HFEC surface inspection at the radius of the frame inner chord for any crack in accordance with
737 NDT Manual Part 6, 51-00-00 Procedure 4 or Procedure 23.
FIGURE 3: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 5 OF 5)
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 42 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
This Figure applies only to: Group 1, Configuration 1.
STA
727
S-18A
2960919
FIGURE 4: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 1 OF 5)
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Copyright © Unpublished
Work - See page 1 for details.  42 of 64

### Page 43 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727
INNER CHORD
FRAME
S-18A
S-18A
WEB
2960920
FIGURE 4: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 2 OF 5)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  Work - See page 1 for details.  Copyright © Unpublished  737-53A1402 RB  43 of 64

### Page 44 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
AFT UPPER FITTING
-1 SHIM
MINIMUM 2 INCHES
(2 LOCATIONS)
6-18/
NEE
HFEC SURFACE
INSPECTION AREA  2960921
FIGURE 4: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 3 OF 5)
Original Issue: July 02, 2021
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Copyright © Unpublished
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### Page 45 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
S-18A
WEB
INNER CHORD
FWD
A-A
OPEN HOLE HFEC
• INSPECTION AREA  2961147
FIGURE 4: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 4 OF 5)
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Copyright © Unpublished
Work - See page 1 for details.  45 of 64

### Page 46

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)2BACB30NX8KBOLTRemove1
(a)2BACN11E4NUTRemove
(b)-BACB30NX8KBOLTRemove2
(b)-BACC30BH8COLLARRemove
(c)(d)1-SHIMRemove
(e)2-FASTENER HOLEInspect3
(f)1144A2619-()INNER CHORDInspect4
(a) Remove and discard existing bolts and nuts from the structure. Refer to 737-600 SRM 51-40-02, 737-700
SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM 51-40-02, 737-800 SRM 51-40-
02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER SRM 51-40-02 as an accepted
procedure.
(b) It is acceptable to remove up to four fasteners and collars to get the access to remove the shim. Refer to
737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM
51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER
SRM 51-40-02 as an accepted procedure.
(c) If an existing shim is present, remove and discard the shim. Use non-metallic tools to remove existing
sealant at the mating surfaces from shimming. Refer to SOPM 20-50-19 for a list of acceptable sealant
removal tools.
(d) Clean the faying surface of the affected parts. Refer to SOPM 20-30-03 for general cleaning procedures.
(e) Do an open hole High Frequency Eddy Current (HFEC) inspection of the fastener holes in all parts in the
stackup for any crack in accordance with 737 NDT Manual Part 6, 51-00-00 Procedure 16.
(f) Do a HFEC surface inspection at the radius of the frame inner chord for any crack in accordance with
737 NDT Manual Part 6, 51-00-00 Procedure 4 or Procedure 23.
FIGURE 4: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTIONS
(SHEET 5 OF 5)
Export Controlled ECCN: 9E991
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Original Issue: July 02, 2021
737-53A1402 RB
46 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 47 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
This Figure applies only to: Group 1, Configuration 1.
STA
727
STA
727
S-18A
2960922
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 1 OF 6)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  47 of 64

### Page 48 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727  INNER CHORD
FRAME
S-18A
S-18A
WEB
2960923
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 2 OF 6)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.  48 of 64

### Page 49 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
AFT UPPER FITTING
SHIM
S-18A
WEB
2960924
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 3 OF 6)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  49 of 64

### Page 50

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1-GAPMeasure1
(b)1BACS40R010C034FSHIMMake
(c)1BACS40R010C034FSHIMLocate
(d)1BACS40R010C034FSHIMDrill
(e)1BACS40R010C034FSHIMDeburr
(f)-TYPE II, CLASS ACHEMICAL CONVER-
SION COATING
Apply
(g)-BMS 10-11, TYPE IPRIMERApply
(h)-BMS 5-95 CLASS B
OR CLASS C
SEALANTApply2
(i)1BACS40R010C034FSHIMInstall (New)
(j)(k)(m)2BACB30NX8K10BOLTInstall (New)3
(j)(k)(m)2BACN11E4NUTInstall (New)
(j)(l)(m)2BACB30NX8K11BOLTInstall (New)
(j)(l)(m)2BACN11E4NUTInstall (New)
(m)(n)(o)-BACB30NX8K()BOLTInstall (New)4
(m)(n)(o)-BACC30BH8COLLARInstall (New)
(p)-BMS 10-11, TYPE IPRIMERApply5
(q)-BMS 3-23, TYPE IIORGANIC CORRO-
SION INHIBITING
COMPOUND
Apply6
(a) Measure the thickness of the unshimmed gap.
For airplanes that have accomplished the preventive modifications or repairs in accordance with Boeing
Service Bulletin 737-53A1325 R00 or R01, measure the unshimmed gap between the S-18A Web and
Retrofit Strap.
For others airplanes measure the unshimmed gap between the S-18A Web and Inner Chord.
(b) Make new shim. Use the profile of the frame inner chord and S-18A web to make the profile of the new
shim. Refer to SOPM 20-50-20 as an accepted procedure.
(c) Temporarily locate the new shim in position to fill the gap. Maintaining a maximum 0.006 inch gap after
shimming and before fastener pull down. Refer to SOPM 20-50-20 as an accepted procedure.
(d) Match drill the two existing holes into the new shim from the frame inner chord.
(e) Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 4 OF 6)
Export Controlled ECCN: 9E991
Copyright © Unpublished
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Original Issue: July 02, 2021
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REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 51

More DataQtyIdentificationNameTaskStep
(f) Apply one coat of chemical conversion coating to all bare surfaces. Refer to SOPM 20-43-03 as an ac-
cepted procedure.
(g) Apply two coats of primer to the new shim. Refer to SOPM 20-41-02 as an accepted procedure.
(h) Apply faying surface seal to both sides of the shim. Refer to SOPM 20-50-19 as an accepted procedure.
(i) Install new shim. For airplanes that have accomplished the preventive modifications or repairs in accordance
with Boeing Service Bulletin 737-53A1325 R01, install the shim between the S-18A Web and Retrofit
Strap. For others airplanes install the shim between the S-18A Web and Inner Chord.
(j) Make sure fastener head is installed common to the STA 727 frame inner chord. Refer to 737-600 SRM
51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM 51-40-02,
737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER SRM 51-
40-02 as an accepted procedure.
(k) For airplanes that have not accomplished the preventive modifications or repairs in accordance with
Boeing Service Bulletin 737-53A1325 R01, install 1/64 oversize fasteners up to 1/32 oversize as required.
Refer to 737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW
(BBJ) SRM 51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or
737-900ER SRM 51-40-02 as an accepted procedure.
For 1/64 oversize use: BACB30NX8K10X + BACN11E4.
For 1/32 oversize use: BACB30NX8K10Y + BACN11E4.
Maintain the per drawing fastener fit when oversizing. The per drawing fastener fit can be transition or
Class 1 depending on the minor model.
Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
(l) For airplanes that have accomplished the preventive modifications or repairs in accordance with Boeing
Service Bulletin 737-53A1325 R01, install 1/64 oversize fasteners up to 1/32 oversize as required. Refer
to 737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ)
SRM 51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-
900ER SRM 51-40-02 as an accepted procedure.
For 1/64 oversize use: BACB30NX8K11X + BACN11E4.
For 1/32 oversize use: BACB30NX8K11Y + BACN11E4.
Maintain the per drawing fastener fit when oversizing. The per drawing fastener fit can be transition or
Class 1 depending on the minor model.
Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
(m) Install wet with BMS 5-95 Class B or Class C sealant. Refer to SOPM 20-50-19 as an accepted procedure.
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 5 OF 6)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
51 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 52

More DataQtyIdentificationNameTaskStep
(n) If fasteners and collars were removed, install new fasteners and collars with same type and size as they
were removed. Refer to 737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02,
737-700IGW (BBJ) SRM 51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM
51-40-02 or 737-900ER SRM 51-40-02 as an accepted procedure.
(o) If required, install 1/64 oversize fasteners up to 1/32 oversize. Refer to 737-600 SRM 51-40-02, 737-700
SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM 51-40-02, 737-800 SRM 51-40-
02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER SRM 51-40-02 as an accepted
procedure.
For 1/64 oversize use: BACB30NX8K()X + BACC30BH8.
For 1/32 oversize use: BACB30NX8K()Y + BACC30BH8.
Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
(p) Apply 1 coat of primer to the head, collar and exposed threads of the bolt. Refer to SOPM 20-41-02 as
an accepted procedure.
(q) Apply one layer of organic corrosion inhibiting compound to the surface of the repair area. Refer to SOPM
20-41-05 as an accepted procedure.
FIGURE 5: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 6 OF 6)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
52 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 53 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
This Figure applies only to: Group 1, Configuration 1.
STA
STA  727
727
S-18A
2960925
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 1 OF 6)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  53 of 64

### Page 54 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727
INNER CHORD
FRAME
___  S-18A
S-18A
WEB
2960926
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 2 OF 6)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  54 of 64

### Page 55 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
INNER CHORD
AFT UPPER FITTING
SHIM
S-18A
WEB
2960927
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 3 OF 6)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  55 of 64

### Page 56

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY
numbers shown below are the number of parts necessary for this figure.
More DataQtyIdentificationNameTaskStep
(a)1-GAPMeasure1
(b)1BACS40R010C034FSHIMMake
(c)1BACS40R010C034FSHIMLocate
(d)1BACS40R010C034FSHIMDrill
(e)1BACS40R010C034FSHIMDeburr
(f)-TYPE II, CLASS ACHEMICAL CONVER-
SION COATING
Apply
(g)-BMS 10-11, TYPE IPRIMERApply
(h)-BMS 5-95 CLASS B
OR CLASS C
SEALANTApply2
(i)1BACS40R010C034FSHIMInstall (New)
(j)(k)(m)2BACB30NX8K10BOLTInstall (New)3
(j)(k)(m)2BACN11E4NUTInstall (New)
(j)(l)(m)2BACB30NX8K11BOLTInstall (New)
(j)(l)(m)2BACN11E4NUTInstall (New)
(m)(n)(o)-BACB30NX8K()BOLTInstall (New)4
(m)(n)(o)-BACC30BH8COLLARInstall (New)
(p)-BMS 10-11, TYPE IPRIMERApply5
(q)-BMS 3-23, TYPE IIORGANIC CORRO-
SION INHIBITING
COMPOUND
Apply6
(a) Measure the thickness of the unshimmed gap.
For airplanes that have accomplished the preventive modifications or repairs in accordance with Boeing
Service Bulletin 737-53A1325 R00 or R01, measure the unshimmed gap between the S-18A Web and
Retrofit Strap.
For others airplanes measure the unshimmed gap between the S-18A Web and Inner Chord.
(b) Make new shim. Use the profile of the frame inner chord and S-18A web to make the profile of the new
shim. Refer to SOPM 20-50-20 as an accepted procedure.
(c) Temporarily locate the new shim in position to fill the gap. Maintaining a maximum 0.006 inch gap after
shimming and before fastener pull down. Refer to SOPM 20-50-20 as an accepted procedure.
(d) Match drill the two existing holes into the new shim from the frame inner chord.
(e) Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 4 OF 6)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
56 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 57

More DataQtyIdentificationNameTaskStep
(f) Apply one coat of chemical conversion coating to all bare surfaces. Refer to SOPM 20-43-03 as an ac-
cepted procedure.
(g) Apply two coats of primer to the new shim. Refer to SOPM 20-41-02 as an accepted procedure.
(h) Apply faying surface seal to both sides of the shim. Refer to SOPM 20-50-19 as an accepted procedure.
(i) Install new shim. For airplanes that have accomplished the preventive modifications or repairs in accordance
with Boeing Service Bulletin 737-53A1325 R01, install the shim between the S-18A Web and Retrofit
Strap. For others airplanes install the shim between the S-18A Web and Inner Chord.
(j) Make sure fastener head is installed common to the STA 727 frame inner chord. Refer to 737-600 SRM
51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM 51-40-02,
737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER SRM 51-
40-02 as an accepted procedure. as an accepted procedures.
(k) For airplanes that have not accomplished the preventive modifications or repairs in accordance with
Boeing Service Bulletin 737-53A1325 R01, install 1/64 oversize fasteners up to 1/32 oversize as required.
Refer to 737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW
(BBJ) SRM 51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or
737-900ER SRM 51-40-02 as an accepted procedure.
For 1/64 oversize use: BACB30NX8K10X + BACN11E4.
For 1/32 oversize use: BACB30NX8K10Y + BACN11E4.
Maintain the per drawing fastener fit when oversizing. The per drawing fastener fit can be transition or
Class 1 depending on the minor model.
Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
(l) For airplanes that have accomplished the preventive modifications or repairs in accordance with Boeing
Service Bulletin 737-53A1325 R01, install 1/64 oversize fasteners up to 1/32 oversize as required. Refer
to 737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ)
SRM 51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-
900ER SRM 51-40-02 as an accepted procedure.
For 1/64 oversize use: BACB30NX8K11X + BACN11E4.
For 1/32 oversize use: BACB30NX8K11Y + BACN11E4.
Maintain the per drawing fastener fit when oversizing. The per drawing fastener fit can be transition or
Class 1 depending on the minor model.
Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
(m) Install wet with BMS 5-95 Class B or Class C sealant. Refer to SOPM 20-50-19 as an accepted procedure.
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 5 OF 6)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
57 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 58

More DataQtyIdentificationNameTaskStep
(n) If the fasteners and collars were removed, install new fasteners and collars with same type and size as
they were removed. Refer to 737-600 SRM 51-40-02, 737-700 SRM 51-40-02, 737-700CONV SRM 51-
40-02, 737-700IGW (BBJ) SRM 51-40-02, 737-800 SRM 51-40-02, 737-800BCF SRM 51-40-02, 737-900
SRM 51-40-02 or 737-900ER SRM 51-40-02 as an accepted procedure.
(o) If required, install 1/64 oversize fasteners up to 1/32 oversize. Refer to 737-600 SRM 51-40-02, 737-700
SRM 51-40-02, 737-700CONV SRM 51-40-02, 737-700IGW (BBJ) SRM 51-40-02, 737-800 SRM 51-40-
02, 737-800BCF SRM 51-40-02, 737-900 SRM 51-40-02 or 737-900ER SRM 51-40-02 as an accepted
procedure.
For 1/64 oversize use: BACB30NX8K()X + BACC30BH8.
For 1/32 oversize use: BACB30NX8K()Y + BACC30BH8.
Deburr and break all sharp edges. Keep a surface finish of 125 Ra or better.
(p) Apply 1 coat of primer to the head, collar and exposed threads of the bolt. Refer to SOPM 20-41-02 as
an accepted procedure.
(q) Apply one layer of organic corrosion inhibiting compound to the surface of the repair area. Refer to SOPM
20-41-05 as an accepted procedure.
FIGURE 6: RIGHT SIDE - STA 727 FRAME INNER CHORD AT S-18A - SHIM INSTALLATION
(SHEET 6 OF 6)
Export Controlled ECCN: 9E991
Copyright © Unpublished
Work - See page 1 for details.
Original Issue: July 02, 2021
737-53A1402 RB
58 of 64
REQUIREMENTS BULLETIN 737-53A1402
ALERTALERT

### Page 59 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
STA
727
S-18A
2960928
FIGURE 7: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTION
(SHEET 1 OF 3)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  59 of 64

### Page 60 (OCR)

REQUIREMENTS BULLETIN 737-53A1402
ALERT  ALERT
SIA
727
INNER CHORD
FRAME
S-18A
WEB
S-18A
S-18A
WEB
- INNER CHORD
A-A
INSPECTION AREA  HFEC SURFACE  2960929
FIGURE 7: LEFT SIDE - STA 727 FRAME INNER CHORD AT S-18A - HIGH FREQUENCY EDDY CURRENT
(HFEC) INSPECTION
(SHEET 2 OF 3)
Original Issue: July 02, 2021
Export Controlled ECCN: 9E991  737-53A1402 RB
Copyright © Unpublished
Work - See page 1 for details.  60 of 64

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