### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-57A1319**  Original Issue: April 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap, Carriage Spindle - Inspection for Corrosion 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.9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL AND/OR TRADE SECRET Copyright © 2012 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 Unpublished Work.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, DreamlinerTM, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, 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. BOEING is a trademark of Boeing Management Company.

Original Issue: April 16, 2012 737-57A1319 1 of 36 6.0Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 2 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2. Data Supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 24 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 25 M. Software Accomplishment Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 C. Parts Necessary for Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 27 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 27 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 FIGURE 1: LOCATE SUB-ASSEMBLY PART NUMBER FOR CARRIAGES AT WBL 254 AND WBL 355 WITH HVOF THERMAL COATED SPINDLES. . . . . . . . . . . . . . . . . . . . . . . . 33 FIGURE 2: INSPECT SUSPECT CARRIAGE SPINDLES FOR CORROSION. . . . . . . . . . . . . 35

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 3 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 4 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Summary**  **Number: 737-57A1319** Original Issue: April 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap, Carriage Spindle - Inspection for Corrosion THIS BULLETIN 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 SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Boeing has recently received reports of corrosion on outboard flap carriages from four operators, on carriage spindles with less than 7,000 flight cycles. Each of these reports was on carriages with Tungsten-Carbide-Cobalt-Chrome coating applied with High Velocity Oxygenated Fuel (HVOF) on the spindle portion. None were reported to have any fractures. The coating had flaked off the lower surface of the spindle, at the root. A crack in the coating can lead to moisture ingress which may begin corroding the alloy steel base metal. If left unchecked, corrosion pits in this area may create a stress concentration where a crack can start in the base metal resulting in the inability of the carriage to sustain limit load. One fractured carriage spindle can be compensated for by the pilot with inputs to the aileron and or rudder. However fractures of both the inboard and the outboard carriage spindles at the forward end of the spindle through the large diameter (the critical section), on a given outboard flap may preclude continued safe flight and landing of the airplane. This service bulletin provides instruction to inspect 737-100/-200/-200C/-300/400/500 carriage spindles with High Velocity Oxy-Fuel (HVOF) thermal coating that are installed at WBL 254 and WBL 355 on the outboard trailing edge flaps for corrosion and missing or flaked coating. Boeing Service Related Problem (SRP) 737-SRP-57-0254 is related to this service bulletin. **ACTION** Review your records or do an inspection for the carriage part number to determine if you have any of the suspect carriage sub-assemblies that have Tungsten-Carbide-Cobalt-Chrome coating applied with High Velocity Oxygenated Fuel (HVOF) thermal coating on the spindle. If you determine that you do have suspect carriages with the HVOF thermal coating on the spindle, inspect for missing or flaked coating and/or base metal corrosion and presence of Corrosion Inhibiting Compound (CIC). Do a detailed inspection or a Borescope inspection on the forward end of the spindle, that is forward of the flap front spar. Inspect the HVOF thermal coated spindles in accordance with Paragraph 1.E., Compliance. Remove and replace the corroded carriages with a new or serviceable carriage.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 5 of 36The replacement of a carriage that has the suspect HVOF thermal coating on the spindle with one that does not have this HVOF coating, will terminate the inspection in this service bulletin for that carriage only. As an option, the suspect carriage may be reworked into a non-suspect condition. Contact Boeing for additional information. If you determine that your airplane does not have any carriage with the HVOF thermal coating, then there is no further action required. **EFFECTIVITY** 737-100, -200, -200C, -300, -400, -500 Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes.

**COMPLIANCE** Refer to Paragraph 1.E., Compliance. The Federal Aviation Administration (FAA) will possibly release another Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin.

**MANPOWER** Refer to Paragraph 1.G., Manpower.

**MATERIAL INFORMATION** None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 6 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 7 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 8 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-57A1319**  Original Issue: April 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap, Carriage Spindle - Inspection for Corrosion THIS BULLETIN 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 SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes

**DESCRIPTION CONFIGURATION**  **GROUP** 737-100, -200, -200C, -300, -400, -500 airplanes.

- 1

Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 **Group Variable Number** 1 PA001 - PA022 1 PA099 1 PA231 - PA232 1 PC001 - PC005 1 PG001 - PG075 1 PG199 1 PG201 - PG230 1 PG251 - PG255 1 PG271 - PG279

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 9 of 36**Group Variable Number** 1 PG301 - PG314 1 PG331 - PG332 1 PG351 - PG356 1 PG375 1 PG401 - PG403 1 PG431 - PG442 1 PG471 - PG475 1 PG501 - PG505 1 PG571 - PG586 1 PG621 - PG630 1 PG651 - PG652 1 PG701 - PG705 1 PH001 1 PH011 - PH013 1 PH021 - PH024 1 PH701 - PH715 1 PH731 - PH732 1 PH741 - PH743 1 PJ001 - PJ009 1 PJ031 - PJ032 1 PJ071 - PJ072 1 PJ101 - PJ119 1 PJ201 - PJ219 1 PJ301 - PJ302 1 PJ551 - PJ561 1 PJ601 - PJ615 1 PJ811 1 PJ816 - PJ817 1 PK026 - PK029 1 PK041 - PK053 1 PK061 - PK070 1 PK081 - PK082 1 PK091 - PK099

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 10 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PK101 - PK103 1 PK111 - PK120 1 PK141 - PK146 1 PK201 - PK204 1 PK211 - PK223 1 PK231 - PK241 1 PK251 - PK258 1 PK271 - PK274 1 PK281 - PK289 1 PK291 1 PK301 - PK318 1 PK341 1 PK351 - PK361 1 PK391 1 PK431 - PK433 1 PK451 - PK452 1 PK461 - PK469 1 PK495 1 PK501 - PK504 1 PK511 - PK515 1 PK519 1 PK521 - PK528 1 PK541 - PK565 1 PK581 1 PK591 - PK599 1 PK601 - PK617 1 PK621 - PK637 1 PK641 - PK642 1 PK661 - PK666 1 PK671 - PK681 1 PK691 - PK697 1 PK711 - PK716 1 PK731 - PK765

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 11 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PK771 - PK779 1 PK801 - PK804 1 PK819 - PK827 1 PK830 1 PK861 - PK863 1 PK871 - PK874 1 PK881 - PK884 1 PK901 - PK938 1 PK971 - PK974 1 PL001 - PL028 1 PL061 1 PL081 1 PL101 - PL113 1 PL151 1 PL171 - PL172 1 PL201 - PL203 1 PL221 1 PL401 - PL417 1 PL421 1 PL441 1 PL451 - PL456 1 PL471 1 PL491 1 PL501 - PL506 1 PL551 - PL562 1 PL581 1 PL601 - PL603 1 PL611 1 PL621 - PL626 1 PL631 - PL632 1 PL711 - PL712 1 PL716 - PL747 1 PL756

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 12 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PL758 1 PL761 - PL770 1 PL781 - PL788 1 PL793 1 PL801 - PL803 1 PM001 - PM006 1 PM016 - PM017 1 PM021 - PM023 1 PM051 - PM066 1 PM101 - PM119 1 PM141 - PM142 1 PM171 1 PM181 1 PM251 - PM255 1 PM281 - PM283 1 PM381 - PM399 1 PM401 - PM417 1 PM541 - PM564 1 PN001 - PN002 1 PN021 - PN043 1 PN081 - PN086 1 PN101 - PN117 1 PN131 - PN163 1 PN401 - PN420 1 PN431 - PN433 1 PN451 - PN456 1 PN471 - PN474 1 PN481 1 PN491 - PN493 1 PN501 - PN502 1 PN511 - PN512 1 PN521 1 PP001 - PP054

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 13 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PP101 - PP169 1 PP181 - PP199 1 PP201 - PP205 1 PP221 1 PP231 - PP243 1 PP281 - PP286 1 PP301 - PP305 1 PP351 - PP353 1 PP376 - PP384 1 PP391 - PP393 1 PP401 - PP440 1 PP471 - PP475 1 PP501 - PP522 1 PP631 - PP634 1 PP651 - PP652 1 PP671 - PP699 1 PP701 - PP733 1 PP771 - PP779 1 PP801 - PP808 1 PP821 - PP827 1 PP831 - PP848 1 PP851 - PP852 1 PP861 - PP877 1 PP891 - PP899 1 PP901 - PP936 1 PP946 - PP948 1 PP951 - PP952 1 PP961 - PP967 1 PP981 - PP991 1 PP993 1 PQ001 - PQ016 1 PQ026 - PQ041 1 PQ051 - PQ092

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 14 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PQ101 - PQ199 1 PQ201 - PQ202 1 PQ221 - PQ237 1 PQ241 - PQ243 1 PQ251 - PQ267 1 PQ281 - PQ299 1 PQ301 - PQ307 1 PQ331 - PQ332 1 PQ341 - PQ348 1 PQ361 - PQ373 1 PQ391 - PQ395 1 PQ401 - PQ418 1 PQ421 1 PQ431 - PQ438 1 PQ447 - PQ448 1 PQ451 1 PQ454 1 PQ471 - PQ475 1 PQ479 - PQ481 1 PQ486 - PQ487 1 PQ491 - PQ493 1 PQ771 - PQ772 1 PQ791 - PQ793 1 PQ801 - PQ805 1 PQ931 - PQ935 1 PQ951 1 PQ971 - PQ997 1 PR001 - PR017 1 PR021 - PR034 1 PR041 - PR045 1 PR061 - PR072 1 PR077 - PR082 1 PR091 - PR092

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 15 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PR096 1 PR101 1 PR121 - PR122 1 PR131 - PR132 1 PR141 - PR143 1 PR161 - PR172 1 PR181 1 PS601 - PS631 1 PS636 - PS638 1 PS641 - PS644 1 PS651 - PS657 1 PS666 - PS669 1 PS691 - PS692 1 PS701 - PS706 1 PS751 - PS799 1 PS811 1 PS836 - PS837 1 PS841 - PS846 1 PS851 - PS852 1 PS856 1 PS861 - PS863 1 PS866 - PS868 1 PS871 - PS874 1 PS896 - PS897 1 PS901 - PS941 1 PS956 - PS957 1 PS961 - PS963 1 PS971 - PS978 1 PT001 - PT015 1 PT021 - PT031 1 PT041 - PT064 1 PT101 - PT105 1 PT121 - PT138

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 16 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PT146 - PT148 1 PT161 - PT170 1 PT181 - PT188 1 PT211 - PT220 1 PT295 1 PT301 - PT309 1 PT331 - PT360 1 PT381 - PT399 1 PT401 - PT438 1 PT501 - PT517 1 PT561 - PT565 1 PT581 - PT586 1 PT611 - PT621 1 PT641 - PT644 1 PT651 - PT656 1 PT671 - PT672 1 PT681 - PT685 1 PT701 - PT703 1 PT716 - PT717 1 PT721 - PT725 1 PT801 - PT834 1 PT851 - PT854 1 PT871 - PT886 1 PT901 - PT930 1 PT971 - PT973 1 PT981 - PT985 1 PT996 1 PU001 - PU025 1 PU301 1 PU311 - PU313 1 PV001 - PV055 1 PV201 - PV209 1 PV226 - PV229

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 17 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PV231 - PV237 1 PV271 - PV272 1 PV281 - PV287 1 PV296 1 PV301 - PV302 1 PV351 1 PV356 - PV357 1 PW001 - PW054 1 PW061 - PW068 1 PW072 1 PW086 - PW088 1 PW091 - PW094 1 PW101 - PW102 1 PW106 1 PW111 - PW120 1 PW156 - PW157 1 PW161 - PW171 1 PW201 - PW252 1 PW261 - PW268 1 PW271 - PW276 1 PW278 1 PW281 - PW293 1 PW296 1 PW301 - PW327 1 PW401 - PW408 1 PW411 - PW418 1 PW421 - PW424 1 PW431 - PW435 1 PW441 - PW450 1 PW461 - PW467 1 PW501 - PW504 1 PW511 - PW522 1 PW524 - PW550

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 18 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PW556 - PW557 1 PW561 - PW564 1 PW571 - PW576 1 PW591 - PW596 1 PW611 - PW622 1 PW631 - PW637 1 PW661 - PW662 1 PW681 - PW683 1 PW701 - PW702 1 PW711 - PW717 1 PW741 - PW742 1 PW761 1 PW771 1 PW831 1 PW851 - PW856 1 PX071 1 PX701 1 PY001 - PY008 1 PY021 - PY022 1 PY031 1 PY036 - PY037 1 PY046 - PY048 1 PY051 - PY053 1 PY056 - PY057 1 PY101 - PY103 1 PY111 - PY113 1 PY131 - PY135 1 PY141 - PY143 1 PY151 - PY154 1 PY156 - PY157 1 PY161 - PY162 1 PY166 1 PY191

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 19 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group**  **Variable Number**1 PY201 1 PY221 - PY222 1 PY231 1 PY241 - PY244 1 PY270 - PY275 1 PY281 1 PY286 1 PY301 - PY304 1 PY321 - PY323 1 PY341 - PY346 1 PY361 - PY362 1 PY381 1 PY401 1 PY409 - PY411 1 PY421 - PY422 1 PY441 1 PY451 1 PY461 - PY463 1 PY591 - PY595 1 PY611 - PY612 1 PY621 1 PY631 1 PY651 1 PY671 - PY672 1 PY721 1 PY741 2. Spares Affected Examine your spares supply for the parts or components identified in this service bulletin. If any parts or components are found, refer to Paragraph 3.B. Work Instruction for the required action

**B. Concurrent Requirements** None.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 20 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT C. Reason**  Boeing has recently received reports of corrosion on outboard flap carriages from four operators, on carriage spindles with less than 7,000 flight cycles. Each of these reports was on carriages with Tungsten-Carbide-Cobalt-Chrome coating applied with High Velocity Oxygenated Fuel (HVOF) on the spindle portion. None were reported to have any fractures. The coating had flaked off the lower surface of the spindle, at the root. A crack in the coating can lead to moisture ingress which may begin corroding the alloy steel base metal. If left unchecked, corrosion pits in this area may create a stress concentration where a crack can start in the base metal resulting in the inability of the carriage to sustain limit load. One fractured carriage spindle can be compensated for by the pilot with inputs to the aileron and or rudder. However fractures of both the inboard and the outboard carriage spindles at the forward end of the spindle through the large diameter (the critical section), on a given outboard flap may preclude continued safe flight and landing of the airplane This service bulletin provides instruction to inspect 737-100/-200/-200C/-300/400/500 carriage spindles with High Velocity Oxy-Fuel (HVOF) thermal coating that are installed at WBL 254 and WBL 355 on the outboard trailing edge flaps for corrosion and missing or flaked coating. Boeing Service Related Problem (SRP) 737-SRP-57-0254 is related to this service bulletin. **D. Description** Review your records or do an inspection for the carriage part number to determine if you have any of the suspect carriage sub-assemblies that have Tungsten-Carbide-Cobalt-Chrome coating applied with High Velocity Oxygenated Fuel (HVOF) thermal coating on the spindle. If you determine that you do have suspect carriages with the HVOF thermal coating on the spindle, inspect for missing or flaked coating and/or base metal corrosion and presence of Corrosion Inhibiting Compound (CIC). Do a detailed inspection or a Borescope inspection on the forward end of the spindle, that is forward of the flap front spar. Inspect the HVOF thermal coated spindles in accordance with Paragraph 1.E., Compliance. Remove and replace the corroded carriages with a new or serviceable carriage. The replacement of a carriage that has the suspect HVOF thermal coating on the spindle with one that does not have this HVOF coating, will terminate the inspection in this service bulletin for that carriage only. As an option, the suspect carriage may be reworked into a non-suspect condition. Contact Boeing for additional information. If you determine that your airplane does not have any carriage with the HVOF thermal coating, then there is no further action required. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 3-7, 4-7 737-100, 737-200, 737-200C

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 21 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Group 1:** 
**Affected Maintenance Zones Zone**  **Model** 307, 407 737-300, 737-400, 737-500 **E. Compliance** The Federal Aviation Administration (FAA) will possibly release another Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. **Table 1: Inspect HVOF thermal coated Outboard Flap, Carriage Spindles at WBL 254 and WBL 355 for missing or Flaked coating and Corrosion.**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Within 90 days af-ter the original issue date of this service bulletin Determine if you haveany suspect carriage installed in accordance withWork Instruction, Paragraph 3.B. Step 1. All airplanes

180 days (a) Within 90 days af-ter the original issue date of this service bulletin or 180 days from the installation of a suspect carriage, whichever occurs later. (a) Inspect the lower surface of the forward end of thespindle at the root, in accordance with Work Instruction, Paragraph 3.B. Step 6. All airplanes with suspect carriage part numbers 65C27409-29 or 65C27409-31 or 65-47821- 30 or unidentifiable part numbers.

(a) Before further flight. Replace the carriage with a serviceable carriage, inaccordance with Work Instruction, Paragraph 3.B. Step 6.b. Missing or flaked coating or base metal corrosion is found.

- Before further flight. Inspect the lower surface of the forward end of the spindle at the root for CIC coverage in accordance with Work Instruction, Paragraph 3.B. Step 6.a.No missing or flaked coating or base metal corrosion is found.

- Before further flight. Apply CIC as necessary, in accordance with Work Instruction, Paragraph 3.B. Step 6.a.CIC does not cover the inspection area.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 22 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Table 1: Inspect HVOF thermal coated Outboard Flap, Carriage Spindles at WBL 254 and WBL**  **355 for missing or Flaked coating and Corrosion. Repeat Interval**  **(Not to Exceed) Compliance Time**  **Action Condition**  (a) Replacing a suspect carriage with a new or serviceable non-suspect carriage, in accordance with Work Instruction, Paragraph 3.B. Step 7, terminates the inspections in this service bulletin for that carriage only. **F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin.

**G. Manpower** This estimate does not include the task hour data given in the service bulletins in Paragraph 1.B., Concurrent Requirements. The table below shows an estimate of the task hours necessary to do this service bulletin for each carriage spindle. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Elapsed Hours Task Hours**  **Number of Per- sons**  **Task**

0.60 0.60 1 Open Access 0.80 0.80 1 Inspect 4.25 17.00 4 Replace 0.60 0.60 1 Close Access 0.75 1.50 2 Test

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 23 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT Elapsed Hours**  **Task Hours Number of Per-**  **sons Task** 

7.00 20.50 TOTAL FOR EACH AIRPLANE CAR- RIAGE SPINDLE

**H. Weight and Balance Changes** None.

**I. Electrical Load Data** Not applicable.

**J. References** 1. Existing Data: a. Service Related Problem (SRP) 737-SRP-57-0254 b. Boeing Parts Standards Document D-590 c. Boeing Drawing 65-88700 d. 737-300/400/500 Aircraft Maintenance Manual (AMM) 27-51-00, 27-51-34, 27-51-44 e. 737-100/200/200C Aircraft Maintenance Manual (AMM) 737-100/200 AMM 27-51-00, 737-100/200 AMM 27-51-72, 737-100/200 AMM 27-51-81 f. Standard Overhaul Practices Manual (SOPM) SOPM 20-50-10, SOPM 20-41-05

2. Data Supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  Trailing Edge Flap Installation and Rigging Procedures 65C16930 Carriage Sub Assy - Outboard Flap 65C27409 Carriage Assy, Outboard Flap, Wing 65-46481 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 24 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT K. Publications Affected**  **Chapter-Section Publication**  27-51 737 Illustrated Parts Catalog 57-53 Component Maintenance Manual 27-51 737 Aircraft Maintenance Manual
DAMAGE TOLERANCE BASED STRUCTURAL INSPECTIONS: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections(DTI) required in the Maintenance Program. No new Damage Tolerance Inspections (DTIs) are required by this Service Bulletin. **L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

**M. Software Accomplishment Summary**

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 25 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 26 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None.

**B. Industry Support Information** Boeing warranty remedies are not available for the inspection, and/or repair procedures given in this service bulletin. **C. Parts Necessary for Each Airplane** 1. Kits/Parts None.

2. Parts and Materials Supplied by the Operator None.

3. Parts Modified and Reidentified None.

4. Parts Removed and Not Replaced None.

**D. Parts Necessary to Change Spares** If you have outboard flap, carriage spindles 65C27409-29 / -31 or 65-47821-30 with the High Velocity Oxygenated Fuel (HVOF) coating, refer to Paragraph 3.B., Work Instructions for the required action.

**E. Special Tooling - Price and Availability** None.

**F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 27 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 28 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:**KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:**1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. 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 are given in 737 SRM, Chapter 51 – Torque limits to tighten nuts and bolts are given in 737 SRM, Chapter 51 4. For approved fastener and process material substitutions, refer to 737 SRM, Chapter 51. Alternate fasteners are given in 737 SRM Chapter 51 5. If the length of any fastener specified in this service bulletin does not meet the 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. 6. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 7. 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. 8. The instructions in Paragraph 3.B., Work Instructions and the figures can include operation of tools or test equipment. Boeing Engineering Tool Drawings, the Illustrated Tool and Equipment Manual, and the Special Tool and Ground Handling Drawing Index contain data on versions of the tools or test equipment that you can use. It is permitted to use replaced tools. It is not permitted to use superseded tools. 9. 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.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 29 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**10. Where the work instructions include installation of a kept part, a new or serviceable part with the same part number can be installed as an alternative to the kept part. 11. This service bulletin includes functional test procedures for the systems changed by this service bulletin. More functional tests can possibly be necessary in accordance with standard maintenance practices because of interruption to other airplane systems. 12. Some Boeing parts are supplied in a temporary configuration. Those parts are identified with a 'U', 'W', or 'Y' in place of the '-' (dash) in the part number. It is permitted to install parts identified with a 'U', 'W', or 'Y' as an alternative to the '-'(dash) part number. Boeing Drawing 005W0900 contains more data. 13. 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. **B. WORK INSTRUCTIONS** 1. Use one of the two following methods to determine if you have any suspect carriages, i.e., carriages with the High Velocity Oxygen Fuel (HVOF) coating, installed at WBL 254 or WBL 355. If you do not have a carriage with HVOF coating, then there is no further action required. All 737-300, -400, -500 carriage sub-assemblies have the base part number 65C27409-( ). The two suspect part numbers are 65C27409-29 and 65C27409-31. All 737-100,-200, -200C carriage sub-assemblies have the base part number 65-47821-( ). The 737-100, -200, -200C carriage sub-assembly suspect part number is 65-47821-30. If you are unable to identify the sub-assembly part number in the form of 65C27409-( ) or 65-47821-( ), you must assume you have a suspect carriage. a. You may use your records, if your record review positively identifies the carriage sub-assembly part number. If your records indicate a sub-assembly 65C27409 with a dash number other than -29, and -31 for 737-300, -400, -500 or 65-47821-30 for 737-100, -200, -200C, then there is no further action required. If your records indicate that you have a sub-assembly part number 65C27409-29 or 65C27409-31 for 737-300, -400, -500 or 65-47821-30 for 737-100, -200, -200C, you have a suspect carriage sub-assembly. b. You can identify the carriage by the sub-assembly part number on the part. Gain access as required to the carriages on the outboard flap at WBL 254 and WBL 355. Removal of the flap fairing may be required to read the part mark information on the bottom side of the carriage. Refer to FIGURE 1 for the location of the Boeing sub-assembly part number. **NOTE:**Care must be taken, as an older assembly number does not preclude a newer sub-assembly carriage with the HVOF coated spindle. 2. Gain access as required to the carriages on the outboard flap at WBL 254 and WBL 355. 3. Supply power to the hydraulic system. Refer to 737-100/200 AMM 27-51-00 and 737-300/400/500 AMM 27-51-00 as an accepted procedure. 4. Extend the flaps to 40 detent or as required, to expose the spindle area of the carriage.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 30 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT NOTE:** For additional access you may manually deploy the flaps beyond the Flap 40 position, down to the screwjack stops, by winding the torque tubes in the main wheel well. 5. Remove power from the hydraulic system. Refer to 737-100/200 AMM 27-51-00 and 737-300/400/500 AMM 27-51-00 as an accepted procedure. 6. For any suspect carriage, gain access through the front of the trailing edge flap for a detailed inspection or an optional Borescope inspection of the carriage spindle forward section. Perform the detailed inspection or the Borescope inspections of the indicated sections of the spindle, looking for missing or flaked coating or base metal corrosion in accordance with FIGURE 2. As an option, replacing a suspect carriage with a new or serviceable non-suspect carriage, in accordance with Work Instruction, Paragraph 3.B Step 7, terminates the inspections in this service bulletin for that carriage only. a. If no indication of missing or flaked coating or base metal corrosion is found, the carriage does not need to be disassembled or removed. Perform a detailed inspection for Corrosion Inhibiting Compound (CIC) coverage in accordance with FIGURE 2. If CIC does not cover the inspection area, apply BMS3-27 or BMS3-25 CIC to the indicated section, in accordance with FIGURE 2. Refer to SOPM 20-41-05 as an accepted procedure. b. If missing or flaked coating or base metal corrosion is found, replace the carriage with a new or serviceable carriage, in accordance with Step 7. **NOTE:**For purposes of this service bulletin, a "serviceable" part can be either a "suspect" part, i.e., a carriage with HVOF coating, or a "non-suspect" part, i.e., a carriage that does not have HVOF coating. Boeing is currently developing service instructions to rework suspect carriages into non-suspect carriages. Contact Boeing for further information. 7. Use the following steps to remove or replace any carriage. **NOTE:**Replacing a suspect carriage, with one that is not coated with HVOF will terminate the inspections for that location. a. Remove the outboard trailing edge flap. Refer to 737-100/200 AMM 27-51-72 or 737-300/400/500 AMM 27-51-34 as an accepted procedure. b. Remove the midflap carriage from the outboard midflap. Refer to 737-100/200 AMM 27-51-81 or 737-300/400/500 AMM 27-51-44 as an accepted procedure. c. Install the midflap carriage in the outboard midflap. Refer to 737-100/200 AMM 27-51-81 or 737-300/400/500 AMM 27-51-44 as an accepted procedure. d. Install the outboard trailing edge flap. Refer to 737-100/200 AMM 27-51-72 or 737-300/400/500 AMM 27-51-34 as an accepted procedure. 8. Supply power to the hydraulic system. Refer to 737-100/200 AMM 27-51-00 or 737-300/400/500 AMM 27-51-00 as an accepted procedure 9. Retract the flaps fully to 0 detent position.

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 31 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**10. Remove power from the hydraulic system. Refer to 737-100/200 AMM 27-51-00 or 737-300/400/500 AMM 27-51-00 as an accepted procedure. 11. Put the airplane back to a serviceable condition

Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 32 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT FIGURE 1: LOCATE SUB-ASSEMBLY PART NUMBER FOR CARRIAGES AT WBL 254 AND WBL 355 WITH**  **HVOF THERMAL COATED SPINDLES (SHEET 1 OF 2)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 33 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) (b) (d)

- 65C27409-29 Carriage Sub-assem- bly part number Identify 1

- 65C27409-31 65-47821-30 (b) (c) (d)

- 65C27409-( ) Carriage Sub-assem- bly part number Identify 2 65-47821-( ) (a) The carriage sub-assembly part number is etched at the bottom of the carriage. (b) Care must be taken, as an older assembly number does not preclude a newer sub-assembly carriage with the HVOF coated spindle (c) This is the location of the part number on older carriage sub-assemblies. Removal of the flap may be required to access this area. (d) Accomplishment of step 2 is only required if no sub-assembly base part number is found in step 1.

**FIGURE 1: LOCATE SUB-ASSEMBLY PART NUMBER FOR CARRIAGES AT WBL 254 AND WBL 355 WITH HVOF THERMAL COATED SPINDLES**  **(SHEET 2 OF 2)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 34 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT FIGURE 2: INSPECT SUSPECT CARRIAGE SPINDLES FOR CORROSION**  **(SHEET 1 OF 2)** Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 35 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** Do a detailed inspection of the forward end of thespindle at the root for missing or flaked coating or base metal corrosion. (a) - - Suspect Carriage Spindle Inspect 1

Do a detailed inspect of the lower surface of the spindle portion of the root for CIC coverage. If CIC does not cover the inspection area, apply or reapply CIC as necessary. Refer to SOPM 20-41-05 as an accepted procedure. Overspray of CIC beyond the indicated oval area is acceptable. (b) (c) - - Suspect Carriage Spindle Inspect 2

(a) As an option, use a zero degree Borescope and inspect the forward end of the spindle through the front of the trailing edge flap for corrosion. (b) If CIC is intact, no reapplication is necessary. (c) It is not required to inspect for CIC coverage if missing or flaked coating or base metal corrosion was found.

**FIGURE 2: INSPECT SUSPECT CARRIAGE SPINDLES FOR CORROSION (SHEET 2 OF 2)**  Export Controlled ECCN: 9E991 - BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2012 737-57A1319 36 of 36 **BOEING SERVICE BULLETIN 737-57A1319 ALERT**  **ALERT**