### Commercial **Airplanes** 

# 737 Service Bulletin **Number: 737-57A1277** Original Issue: July 25, 2002 Revision 3: May 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2002 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. 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, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery 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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 1 of 50 4.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 2 of 50 **BOEING SERVICE BULLETIN 737-57A1277**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 28 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 29 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 29 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 FIGURE 1: CARRIAGE SPINDLE INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD. . . . . . . . . . . . . 38 FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD. . . . . . . . . . . 40 FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD. . . . . . 43 FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD. . . . . 45 FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK. . . . . . . . . . . . . . . . 48

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 3 of 50 **BOEING SERVICE BULLETIN 737-57A1277**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 4 of 50 **BOEING SERVICE BULLETIN 737-57A1277**

BLANK PAGE

### Commercial **Airplanes** 

# 737 Service Bulletin **Revision Transmittal Sheet Number: 737-57A1277**  Original Issue: July 25, 2002 Revision 3: May 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 is related to this service bulletin. The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. No more work is necessary on the airplane(s) changed in accordance with Revision 2 of this service bulletin.

**REASON FOR REVISION** This revision is sent to provide information for compliance table 1 that was in revision R1 but was inadvertantly deleted in revision R2. These sections were changed: 1. Section 1.E. Compliance, Table 1 - re-inserted "Work Package 1 (NDT): Not Required" 2. Section 1.F. Approval, changed revision 2 to revision 3. 3. Section 3.A. General Information, deleted note 1. "The sequence of steps ... can be changed". The data given in Information Notice 737-57A1277 IN 03 is included in this revision.
Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. **REVISION HISTORY** July 25, 2002 Original Issue: November 25, 2003 Revision 1:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 5 of 50June 09, 2011 Revision 2: May 16, 2012 Revision 3:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 6 of 50 **BOEING SERVICE BULLETIN 737-57A1277**

### Commercial **Airplanes** 

# 737 Service Bulletin **Summary Number: 737-57A1277**  Original Issue: July 25, 2002 Revision 3: May 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking **CONCURRENT REQUIREMENTS** None **BACKGROUND** This service bulletin provides instructions for the inspection of the outboard midflap carriage spindles and will ensure that the carriage spindles are not fractured. 42 severed outboard midflap carriage spindles (resulting from corrosion, fatigue and/or improper overhaul) have been reported by 23 operators. The most critical section for a fracture is at the forward end of the spindle through the large diameter. Of the 42 reported fractures, 24 have been thru the critical "A" location and 18 reported at the "B" spindle location . The fractures occurred on 737-200/-300/-400/-500 airplanes. If one carriage spindle fractures in the forward end of the spindle (the critical section), the pilot can compensate for it with inputs to the aileron and/or rudder. However, if both the inboard and outboard spindles fracture in the critical section on an outboard flap, continued safe flight and landing of the airplane may be precluded. Boeing received a recent report about a 737-200 having both inboard and outboard spindles (number 7 & 8 carriage spindles) severed on the right outboard flap during landing. The flight crew reported a loud bang at approximately 500 feet AGL followed by the airplane rolling off hard to the right. Corrective action was required to maintain level flight. As a result, a gap check was developed to detect severed spindles only at the critical "A" location. Whereas, the NDT inspection, in the previous issue of this service bulletin, checks the critical "A" location thru the "B" location up to the cross bolt for the spherical bearing. **ACTION** Extend the flaps. For the left and right midflaps, do an NDT inspection or Gap Check of the spindle at each carriage (two carriages per midflap) at the specified time. The NDT inspection or Gap Check will detect a fracture in the spindle. If the spindle is fractured or severed, remove it from service, discard it, and notify Boeing. Then, install a new or serviceable carriage spindle. If you notice corrosion at the exposed portion of the spindle, remove the carriage and overhaul the spindle. **EFFECTIVITY** All 737-100, -200, -200C, -300, -400, and -500 airplanes. **COMPLIANCE** Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 is related to this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 7 of 50The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. See Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection given in this service bulletin. **MANPOWER Elapsed Hours**  **Total Task Hours Work Package**  8 16 1 1 2 2

**MATERIAL INFORMATION** None

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 8 of 50 **BOEING SERVICE BULLETIN 737-57A1277**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 9 of 50 **BOEING SERVICE BULLETIN 737-57A1277**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 10 of 50 **BOEING SERVICE BULLETIN 737-57A1277**

BLANK PAGE

### Commercial **Airplanes** 

# 737 Service Bulletin **Number: 737-57A1277** Original Issue: July 25, 2002 Revision 3: May 16, 2012 ATA System: 5752 **SUBJECT:** WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle - Inspection for Cracking **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index Document D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** 737-100, -200, -200C, -300, -400 and -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 1 PG301 - PG314 1 PG331 - PG332

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 11 of 50**Group Variable Number** 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 1 PK101 - PK103 1 PK111 - PK120

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 12 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PK771 - PK779 1 PK801 - PK804

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 13 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PL758 1 PL761 - PL770

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 14 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PP101 - PP169 1 PP181 - PP199

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 15 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PQ101 - PQ199 1 PQ201 - PQ202

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 16 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PR096 1 PR101

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 17 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PT146 - PT148 1 PT161 - PT170

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 18 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PV231 - PV237 1 PV271 - PV272

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 19 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PW556 - PW557 1 PW561 - PW564

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 20 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 1 PY201 1 PY221 - PY222

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 21 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Group**  **Variable Number**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 None **B. Concurrent Requirements** None **C. Reason** This service bulletin provides instructions for the inspection of the outboard midflap carriage spindles and will detect severed carriage spindles.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 22 of 50 **BOEING SERVICE BULLETIN 737-57A1277**42 severed outboard midflap carriage spindles (resulting from corrosion, fatigue and/or improper overhaul) have been reported by 23 operators. The most critical section for a fracture is at the forward end of the spindle through the large diameter. Of the 42 reported fractures, 24 have been thru the critical "A" location and 18 reported at the "B" spindle location . The fractures occurred on 737-200/-300/-400/-500 airplanes. If one carriage spindle fractures at the forward end of the spindle (the critical section), the pilot can compensate for it with inputs to the aileron and/or rudder. However, if both the inboard and outboard spindles fracture in the critical section on a outboard flap, continued safe flight and landing of the airplane may be precluded. Boeing received a recent report about a 737-200 having both inboard and outboard spindles (number 7 & 8) severed on the right outboard flap during landing. The flight crew reported a loud bang approximately 500 feet AGL followed by the airplane rolling off hard to the right. Corrective action was required to maintain level flight. As a result, a gap check was developed to detect severed spindles only at the critical "A" location. Revision 1 is issued to add a gap check to determine if a spindle has been fractured at the critical "A" location. An additional compliance time is also added for this new check. This gap check is under Work Package 2. The original NDT inspection is now Work Package 1. The NDT compliance times have also been revised. Revision 2 is issued to revise the inspection intervals listed in compliance tables 1 and 2 and add a new compliance table 3. The intent of Information Notice 737-57A1277 IN 01 has been incorporated into this revision. The data given in Information Notice 737-57A1277 IN 02 is included in this revision. One of the 2 AMOC listed on IN 02 is suspended. The AMOC that referenced the use of ultrasonic inspection method to confirm a severed spindle after performing the gap check has been incorporated. Revision 3 is issued to provide information for compliance table 1 that was in revision R1 but was inadvertantly deleted in revision R2. This information was provided in Information Notice 737-57A1277 IN 03 and has been incorporated. **D. Description** Extend the flaps. For the left and right midflaps, do an NDT inspection of the spindle of each carriage (two carriages per midflap). The NDT inspection will detect a fractured or severed spindle at the critical "A" location and thru the "B" location to the bolt hole for the spherical bearing. See compliance paragraph for threshold and interval. Expand the flaps. Do a gap check on each outboard flap assembly to detect a severed spindle. See compliance paragraph for threshold and interval. If the spindle is fractured or severed, remove it from service, discard it, and notify Boeing; then install a new or serviceable spindle. If you find corrosion at the exposed portion of the spindle, remove the carriage and overhaul the spindle. Revision 1 - More inspections are necessary on airplanes inspected as shown in the initial release of this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 23 of 50 **BOEING SERVICE BULLETIN 737-57A1277**Revision 2 - More work is necessary on airplanes changed in accordance with the original issue and Revision 1 of this service bulletin. Revision 3 - No more work is necessary on the airplane(s) changed in accordance with Revision 2 of this service bulletin. 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 **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 307, 407 737-300, 737-400, 737-500 **E. Compliance** Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 is related to this service bulletin. The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Boeing recommends:
**Table 1 For 737-100/-200/200C/-300/-400/-500 with NEW (never been overhauled) Carriage Spindles :**  **INTERVAL Whichever is later THRESHOLD**  Work Package 1 (NDT): 15 Days or 150 flight cycles > 20,000 flight cycles or 8 Years in-service since spindle was new, whichever is less ** Work Package 2 (Gap Check): 3 Days or 30 flight cycles* Work Package 1 (NDT): 45 Days or 450 flight cycles 12,000 to 20,000 flight cycles since spindle was new ** Work Package 2 (Gap Check): 15 Days or 150 flight cycles

* Work Package 1 (NDT): Not Required < 12,000 flight cycles since spindle was new **Work Package 2 (Gap Check): Not Required* The gap check does not have to be done at the same time as an ultrasonic inspection; after doing an ultrasonic inspection, the interval for doing the next gap check can be measured from the ultrasonic inspection.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 24 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Table 1**  **For 737-100/-200/200C/-300/-400/-500 with NEW (never been overhauled) Carriage Spindles : INTERVAL Whichever is later**  **THRESHOLD  If the number of flight cycles or time since new cannot be positively determined by reviewing maintenance records, the threshold is considered the same as carriage spindles having greater than 20,000 flight cycles.
** Table 2** **For Overhauled Carriage Spindles with documented life less than 40,000 flight cycles: INTERVAL -300/-400/-500 Whichever is**  **later INTERVAL -100/-200/-200C**  **Whichever is later THRESHOLD; flight cycles**  **since last overhaul** Work Package 1 (NDT): 15 Days or 150 flight cycles > 20,000 flight cycles, or 8 Years in service since spindle was overhauled, whichever is less ** Work Package 2 (Gap Check): 3 Days or 30 flight cycles *

Work Package 1 (NDT): 15 Days or 150 flight cycles. Work Package 1 (NDT): 15 Days or 150 flight cycles.12,000 to 20,000 flight cycles, or 8 Years in servicesince spindle was overhauled, whichever is less ** Work Package 2 (Gap Check): 3 Days or 30 flight cycles * Work Package 2 (Gap Check): 3 Days or 30 flight cycles * Work Package 1 (NDT): 180 Days or 1,500 flight cycles Work Package 1 (NDT): 60 Days or 500 flight cycles 3,000 to 12,000 flight cycles** Work Package 2 (Gap Check): 14 Days or 140 flight cycles * Work Package 2 (Gap Check): 7 Days or 70 flight cycles * Work Package 1 (NDT): Not Required Work Package 1 (NDT): 180 Days or 1,500 flight cycles < 3,000 flight cycles ** Work Package 2 (Gap Check): Not Required Work Package 2 (Gap Check): Not Required* The gap check does not have to be done at the same time as an ultrasonic inspection; after doing an ultrasonic inspection, the interval for doing the next gap check can be measured from the ultrasonic inspection. ** If the number of flight cycles or time since last overhaul cannot be positively determined by reviewing maintenance records, the threshold is considered the same as carriage spindles having greater than 20,000 flight cycles.
**Table 3 For Overhauled Carriage Spindles with 40,000 or more flight cycles since new or if undocumented**  **life: INTERVAL -300/-400/-500 Whichever is**  **later INTERVAL -100/-200/-200C**  **Whichever is later THRESHOLD; flight cycles**  **since last overhaul** Work Package 1 (NDT): 6 Days or 60 flight cycles > 20,000 flight cycles,or 8 years in service since spindle was overhauled, whichever is less ** Work Package 2 (Gap Check): Daily or 20 flight cycles *

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 25 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Table 3**  **For Overhauled Carriage Spindles with 40,000 or more flight cycles since new or if undocumented life:**  **INTERVAL -300/-400/-500 Whichever is later**  **INTERVAL -100/-200/-200C Whichever is later**  **THRESHOLD; flight cycles since last overhaul**  Work Package 1 (NDT): 15 Days or 150 flight cycles Work Package 1 (NDT): 6 Days or 60 flight cycles < 20,000 flight cycles, or 8 Years in service since spindle was overhauled, whichever is less ** Work Package 2 (Gap Check): 3 Days or 30 flight cycles * Work Package 2 (Gap Check): Daily or 20 flight cycles ** The gap check does not have to be done at the same time as an ultrasonic inspection; after doing an ultrasonic inspection, the interval for doing the next gap check can be measured from the ultrasonic inspection. ** If the number of flight cycles or time since last overhaul cannot be positively determined by reviewing maintenance records, the threshold is considered the same as carriage spindles having greater than 20,000 flight cycles. **F. Approval** This service bulletin was inspected by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved. This service bulletin and the FAA approval were based on the airplane in its original Boeing delivery configuration or as modified by other FAA approved Boeing changes. The Manager of the FAA Seattle Aircraft Certification Office (ACO) approves the accomplishment of the applicable inspections, investigative, and corrective actions at the corresponding compliance times specified in Service Bulletin 737-57A1277, Revision 3 as an AMOC to the inspections, investigative and corrective actions with the corresponding compliance times specified in Service Bulletin 737-57A 1277, Revision 1, required by paragraphs (g), (h), (i), (j), (k), (I), and (n) of AD 2010-15-08. When this service bulletin specifies contacting Boeing for repair instruction, the repair instructions must be approved by the FAA in accordance with paragraph (t) of the AD. All provisions of AD 2010-15-08 that are not specifically referenced in this paragraph remain fully applicable and must be complied with accordingly. 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** The table below shows an estimate of the task-hours necessary to do this inspection for each airplane. 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 find the tools.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 26 of 50 **BOEING SERVICE BULLETIN 737-57A1277 Work Package 1 (NDT Ultrasonic and General Visual Inspection)**  **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**
1.5 3 2 Open Access 5.0 10 2 Inspect 1.5 3 2 Close Access 8 16 TOTAL FOR EACH AIRPLANE **Work Package 2 (Gap Check) Elapsed Hours**  **Task-Hours Number of Per-**  **sons Task** 

1 2 2 Inspect 1 2 TOTAL FOR EACH AIRPLANE **H. Weight and Balance Changes** None **I. Electrical Load Data** None **J. References** 1. Existing Data: a. 737 Nondestructive Test (NDT) Manual, Part 4, Subject 57-50-02. b. 737 Overhaul Manual (OHM), Subject 57-53-35. c. 737 Component Maintenance Manual (CMM), Subject 57-53-36. d. 737 Airplane Maintenance Manual (AMM), Subject 27-51-72, 737-100/200 AMM 27-51-81. e. 737-300/400/500 Airplane Maintenance Manual (AMM), Subject 27-51-34, 737-300/400/500 AMM 27-51-44. f. Boeing Service Bulletin 737-57A1218, "WINGS - Trailing Edge Flaps - Outboard Flap Carriage Spindle Repair". g. Boeing Standard Overhaul Practices Manual (BSOPM) 20-42-09 h. Federal Aviation Administration (FAA) Airworthiness Directive AD 2010-15-08 2. Data supplied with this Service Bulletin: None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 27 of 50 **BOEING SERVICE BULLETIN 737-57A1277**3. Installation Drawings Used in the Preparation of this Service Bulletin: None **K. Publications Affected** 1. Publications: None. 2. 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. This service bulletin affects FCS but no new DTIs are necessary.
**L. Interchangeability and Intermixability of Parts** None

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 28 of 50 **BOEING SERVICE BULLETIN 737-57A1277 2. MATERIAL INFORMATION**  **A. Material - Price and Availability** None **B. Industry Support Information** Boeing warranty remedies are not available for the inspection given in this service bulletin. **C. Parts Necessary For Each Airplane** 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator: None.
**Notes Name**  **QTY Part Number /**  **Specification** (a) Clay 4 oz. * * Any type of stable clay is acceptable (a) An Example is: Permoplast Modeling Clay AMACO, Phone: 317- 244-6871 or 800-374-1600 4717 W. 16th St. Indianapolis, IN 46222 USA
3. Parts Modified and Reidentified: None. 4. Parts Removed and Not Replaced: None. **D. Parts Necessary to Change Spares** None **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. Inspect operator tool supply to make sure all necessary tools are available.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 29 of 50 **BOEING SERVICE BULLETIN 737-57A1277**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 30 of 50 **BOEING SERVICE BULLETIN 737-57A1277**

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. The work instructions are divided into work packages. Task Hours and Elapsed Hours for each package are given in Paragraph 1.G., Manpower. You can do each work package independently. 4. 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 in Structural Repair Manual (SRM) Chapter 51 – Torque limits to tighten nuts and bolts are in SRM Chapter 51 5. Use the approved fastener and process material substitutions in accordance with SRM Chapter 51. Alternate fasteners are listed in SRM Chapter 51. 6. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures, and SWPM 20-10-19 for the wire separation requirements, as accepted procedures. 7. 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. 8. 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 31 of 50 **BOEING SERVICE BULLETIN 737-57A1277**9. 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. 10. 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. 11. 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. 12. 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. 13. 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. The removed part can be discarded if a new or serviceable part is installed. 14. 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. 15. 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. **B. WORK INSTRUCTIONS WORK PACKAGE 1 - On Wing NDT Ultrasonic & General Visual Inspection**  1. Extend outboard flaps to detent 40 by doing the following: a. For 737-100/-200/-200C airplanes, pressurize hydraulic system A; refer to 737 Airplane Maintenance Manual (AMM), Subject 27-51-0. For 737-300/-400/-500 airplanes, activate trailing edge flap system; refer to AMM 27-51-00. Or, you can use you own equivalent procedure. b. Extend Flaps to detent 40.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 32 of 50 **BOEING SERVICE BULLETIN 737-57A1277**c. For 737-100/-200/-200C airplanes, depressurize hydraulic system A; refer to AMM 27-51-0. For 737-300/-400/-500 airplanes, deactivate trailing edge flap system; refer to AMM 27-51-00. Or, you can use your own equivalent procedure. 2. For each carriage spindle of the left and right outboard midflap (two carriage spindles on each flap), do an NDT Ultrasonic and General Visual Inspection in accordance with Figure 1. 3. If the Figure 1 NDT Ultrasonic indicates a cracked, or severed spindle - prior to further flight: a. Remove the midflap from the airplane and remove the carriage from the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Install a new or serviceable spindle, refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package 1. b. Alternatively, remove the midflap from the airplane and remove the carriage from the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Remove the sleeve (if any) from the spindle of the carriage. Perform a detailed inspection of the spindle for damage in accordance with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes) or 737 CMM, Subject 57-53-36 (737-300/-400/-500 airplanes). If inspection indicates a severed spindle, the spindle cannot be overhauled and must be discarded. Notify Boeing of your findings. Install a new or serviceable spindle, refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package 1. If inspection indicated a crack or corrosion go to 4.d. 4. If General Visual Inspection indicates cracking or corrosion in the exposed portion of the spindle - prior to further flight - do the following: a. Remove the midflap from the airplane and remove the carriage from the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. b. Install a new or serviceable carriage spindle into the midflap and the midflap on the airplane. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6.0 of Work Package 1. c. Alternatively, remove the midflap from the airplane and remove the carriage from the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Remove the sleeve (if any) from the spindle of the carriage. Perform a Detailed Inspection of the spindle for damage in accordance with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes) or 737 CMM, Subject 57-53-36 (737-300/-400/-500 airplanes). d. Overhauled carriage spindles shall be done in accordance with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes) or 737 CMM, Subject 57-53-36 (737-300/-400/-500 airplanes) and Service Bulletin 737-57A1218, Revision 5. **NOTE:**When overhauling the carriage, all finishes and plating must be removed from the spindle

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 33 of 50 **BOEING SERVICE BULLETIN 737-57A1277**e. If the spindle does not pass the inspection requirements, remove the carriage from service and discard it. Notify Boeing:Send your report to: BOEING COMMERCIAL AIRPLANES GROUP ATTENTION: MANAGER, AIRLINE SUPPORT f. Install a new or serviceable carriage spindle, on the midflap and airplane. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package 1. 5. If the NDT Ultrasonic and General Visual Inspection of the spindle shows it is not fractured or severed, and if no corrosion or cracking is noticed, go to 6.0 below. 6. Put the airplane back to a serviceable condition. 7. Then, repeat Work Package 1 in accordance with compliance intervals provided in Paragraph 1.E., Compliance. Except as spindles gain flight cycles and move from one grouping threshold row to another, they are subject to repetitive inspection intervals corresponding to the new threshold grouping. **WORK PACKAGE 2 - Midflap/Spindle Carriage Gap Check** 1. Extend outboard flaps to detent 40 by doing the following: a. For 737-100/-200/-200C airplanes, pressurize hydraulic system A; refer to AMM 27-51-0. For 737-300/-400/-500 airplanes, activate trailing edge flap system; refer to AMM 27-51-00. Or, you can use you own equivalent procedure. b. Extend Flaps to detent 40. c. For 737-100/-200/-200C airplanes, depressurize hydraulic system A; refer to AMM 27-51-0. For 737-300/-400/-500 airplanes, deactivate trailing edge flap system; refer to AMM 27-51-00. Or, you can use you own equivalent procedure. 2. For the left wing and right wing outboard midflap, do ONE of the following checks to determine movement of the midflap with respect to the carriage spindle (be sure to use proper lighting): a. Gap Check - Clay Method: in accordance with Figure 2 and Figure 3 or: b. Gap Check - Measurement Method: in accordance with Figure 4 and Figure 5 or: c. Gap Check - Midflap Leading Edge Relative Movement Check: in accordance with Figure 6. 3. (This lettered work instruction step is no longer used.)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 34 of 50 **BOEING SERVICE BULLETIN 737-57A1277**4. If you find differential movement between the midflap and carriage spindle (from Figure 2 & 3, or Figure 4 & 5, or Figure 6), this is a positive indication of a severed spindle. Prior to further flight, do the following steps or first do an ultrasonic inspection in accordance with Work Package 1, Section 3.B.2 for confirmation of a severed spindle: a. Remove the midflap from the airplane and remove the carriage from the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Install a new or serviceable carriage spindle into the midflap and the midflap on the airplane. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Go to paragraph 6. of Work Package 2 b. Alternatively, remove the midflap from the airplane and remove the carriage from the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44. Remove the sleeve (if any) from the spindle of the carriage. Do a Detailed Inspection to determine if there is corrosion, a crack, or severed spindle. In accordance with 737 OHM 57-53-35 (737-100/-200/-200C), or CMM 57-53-36 (737-300/-400/-500) for inspection criteria of an acceptable spindle. (1) If spindle is severed, or has non-repairable crack, or non-repairable corrosion, discard it and notify Boeing and provide service time and cycles of carriage spindle. Prior to further flight, install a new or serviceable carriage spindle on the midflap. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44, or your equivalent procedure. (2) If spindle has repairable crack, and/or corrosion, prior to further flight, install a new or serviceable carriage spindle. Overhauled carriage spindles shall be done in accordance with 737 OHM, Subject 57-53-35 (737-100/-200/-200C airplanes), or 737 CMM, Subject 57-53-36 (737-300/-400/-500 airplanes) and Service Bulletin 737-57A1218, Revision 3, or later revision. (3) If carriage spindle is not severed and no corrosion and crack is present, it can be reinstalled on midflap. However, before reinstalling, investigate to see if there is any damage that would cause the midflap to move away from the carriage and repair accordingly. Install the carriage spindle and repeat Work Package 2 to verify disposition of your investigation. Refer to AMM 27-51-72 (737-100/-200/-200C) & 737-100/200 AMM 27-51-81 or AMM 27-51-34 (737-300/-400/-500) & 737-300/400/500 AMM 27-51-44, or your equivalent procedure for installing the carriage spindle. (4) Go to paragraph 6. of Work Package 2. 5. If the midflap does not separate from the clay (from the checks in Figure 2 and Figure 3), or there is no differential movement between the carriage and midflap, go to 6.0. 6. Put the airplane back to a serviceable condition. 7. Then, repeat Work Package 2 in accordance with compliance intervals provided in Paragraph 1.E., Compliance. Except as spindles gain flight cycles and move from one grouping threshold row to another, they are subject to repetitive inspection intervals corresponding to the new threshold grouping.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3: May 16, 2012 35 of 50 **BOEING SERVICE BULLETIN 737-57A1277 FIGURE 1: CARRIAGE SPINDLE INSPECTION**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 36 of 50 **BOEING SERVICE BULLETIN 737-57A1277**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES QTY**  **PROCESS NAME**  **TASK STEP**  It is not necessary to remove thecover plate to do the NDT inspection. Ultrasonic Inspection will find a severed spindle in the section shown. The important section covers the critical "A" location thru the "B" location to the cross bolt. - 737 NDT Part 4, Subject 57-50-02 Carriage Spindle Inspect 1

on exposed areas as shown. Look for signs of corrosion and cracks. - General Visual In- spection Carriage Spindle Inspect 2

**FIGURE 1: CARRIAGE SPINDLE INSPECTION (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 37 of 50 **BOEING SERVICE BULLETIN 737-57A1277 FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 38 of 50 **BOEING SERVICE BULLETIN 737-57A1277**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 items necessary for inboard carriage.
**NOTES QTY**  **NAME TASK**  **STEP** to flap surface (for clay), as needed.

- Parting Compound Apply 1 (approximately 1X1X1 inch) to side/bottom of the carriage and touching lower surface of midflap as shown. Use grease as a parting compound between clay and flap 1 Clay Apply 2

to area indicated - normal to the midflap surface. Use one or two people. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. - - Apply Force 3

between clay and surface of midflap during the applied force. If spindle is severed, you will see a gap between the clay and the surface of midflap - hence movement of the midflap away from the carriage . If the spindle is not severed, the midflap surface will stay in contact with the clay. - Gap Look for 4

1 Clay Remove 5

**FIGURE 2: INBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 39 of 50 **BOEING SERVICE BULLETIN 737-57A1277 FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 40 of 50 **BOEING SERVICE BULLETIN 737-57A1277**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 items necessary for outboard carriage.

**FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 41 of 50 **BOEING SERVICE BULLETIN 737-57A1277 NOTES**  **QTY NAME**  **TASK STEP**  to flap surface (for clay) as needed.

- Parting Com- pound Apply 1 (approximately 1X1X1 inch) to side/bottom of the carriage and touching lower surface of midflap as shown. Use grease as a parting compound between clay and flap. 1 Clay Apply 2

at ONE of the two locations indicated - the midflap OR aft fairing as follows: If you choose the midflap: Apply the force to area indicated - normal to the midflap surface. Use one or two people. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. - - Apply Force 3

If you choose the aft fairing: Apply the force near the end of fairing in an upward direction. You can use one person for this. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. between clay and surface of midflap during the applied force. If spindle is severed, you will see a gap between the clay and the surface of midflap - hence movement of the midflap away from the carriage. If the spindle is not severed, the midflap surface will stay in contact with the clay. - Gap Look for 4

1 Clay Remove 5

**FIGURE 3: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - CLAY METHOD (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 42 of 50 **BOEING SERVICE BULLETIN 737-57A1277 FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 43 of 50 **BOEING SERVICE BULLETIN 737-57A1277**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**NOTES QTY**  **NAME TASK**  **STEP** on midflap (that is inline with) and a fixed feature on the carriage with a pen (or equivalent). - Measurement Loca- tion Mark 1 between the marked location on the midflap and the fixed feature on the carriage. - Measurement Make a 2 to area indicated - normal to the midflap surface. Use one or two people. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. - - Apply Force 3

between the same end points as taken in Step 1 above during the applied force. If spindle is severed, you will have a differential measurement between your initialmeasurement and this measurement - hence movement of the midflap away from the carriage . If the spindle is not severed, your second measurement will be the same as your initial measurement. - Measurement Make a 4

**FIGURE 4: INBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 44 of 50 **BOEING SERVICE BULLETIN 737-57A1277 FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 45 of 50 **BOEING SERVICE BULLETIN 737-57A1277**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 46 of 50 **BOEING SERVICE BULLETIN 737-57A1277 NOTES**  **QTY NAME**  **TASK STEP**  on midflap (that is inline with) and a fixed feature on the carriage with a pen (or equivalent). - Measurement Loca- tion Mark 1 between the marked location on the midflap and the fixed feature on the carriage. - Measurement Make a 2 at ONE of the two locations indicated - the midflap OR aft fairing as follows: If you choose the midflap: Applythe force to area indicated - normal to the midflap surface. Use one or two people. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. - - Apply Force 3

If you choose the aft fairing: Apply the force near the end of fairing in an upward direction. You can use one person for this. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. between the same end points as taken in Step 1 above during the applied force. If spindle is severed, you will have a differential measurement between your initialmeasurement and this measurement - hence movement of the midflap away from the carriage. If the spindle is not severed, your second measurement will be the same as your initial measurement - hence no movement. - Measurement Make a 4

**FIGURE 5: OUTBOARD CARRIAGE / MIDFLAP GAP CHECK - MEASUREMENT METHOD (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 47 of 50 **BOEING SERVICE BULLETIN 737-57A1277 FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 48 of 50 **BOEING SERVICE BULLETIN 737-57A1277**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 49 of 50 **BOEING SERVICE BULLETIN 737-57A1277 NOTES**  **QTY NAME**  **TASK STEP**  STEPS 1 THRU 3 ARE FOR THE INBOARD CARRIAGE SPINDLEposition with respect to carriage yoke. Note this relationship. - Leading Edge Look at 1 to area indicated - normal to the midflap surface. Use one or two people. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. - - Apply Force 2

of the leading edge of the midflap with respect to the carriage yoke while the force is applied as described above. Note the position of the leading edge of themidflap with respect to carriage yoke. If there is a difference, then the spindle is severed. If there is no difference, the the spindle is not severed. - Movement Look for 3

STEPS 4 THRU 6 ARE FOR THE OUTBOARD CARRIAGE SPINDLEposition with respect to carriage yoke. Note this relationship - Leading Edge Look at 4 at ONE of the two locations indicated - the midflap OR aft fairing as follows: If you choose the midflap: Applythe force to area indicated - normal to the midflap surface. Use one or two people. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. - - Apply Force 5

If you choose the aft fairing: Apply the force near the end of fairing in an upward direction. You can use one person for this. The force applied shall be just enough to (slightly) lift the carriage off of the dead weight rollers. of the leading edge of the midflap with respect to the carriage yoke while the force is applied as described above. Note the position of the leading edge of themidflap with respect to carriage yoke. If there is a difference, then the spindle is severed. If there is no difference, the the spindle is not severed - Movement Look for 6

**FIGURE 6: MIDFLAP LEADING EDGE RELATIVE MOVEMENT CHECK (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 25, 2002 737-57A1277 Revision 3 May 16, 2012 50 of 50 **BOEING SERVICE BULLETIN 737-57A1277**