### Commercial **Airplanes** 

# 747 Service Bulletin **Number: 747-56A2012** Original Issue: August 24, 2006 Revision 1: August 12, 2010 ATA System: 5611 **SUBJECT:** WINDOWS - Flight Compartment - Flight Compartment Windows - Inspection of Glass No. 2 and No. 3 Windows for Cracks in the Fail-Safe Interlayer 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2006 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 1 of 52 8.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 2 of 52 **BOEING SERVICE BULLETIN 747-56A2012**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 30 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 31 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 32 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 FIGURE 1: NO. 2 AND NO. 3 WINDOW IDENTIFICATION. . . . . . . . . . . . . . . . . . . . . . . 36 FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW DETAILED INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW DETAILED INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 3 of 52 **BOEING SERVICE BULLETIN 747-56A2012**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 4 of 52 **BOEING SERVICE BULLETIN 747-56A2012**

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### Commercial **Airplanes** 

# 747 Service Bulletin **Revision Transmittal Sheet Number: 747-56A2012**  Original Issue: August 24, 2006 Revision 1: August 12, 2010 ATA System: 5611 **SUBJECT:** WINDOWS - Flight Compartment - Flight Compartment Windows - Inspection of Glass No. 2 and No. 3 Windows for Cracks in the Fail-Safe Interlayer This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** Federal Aviation Administration (FAA) Airworthiness Directive FAA AD 2007-15-10 is related to this service bulletin. No more work is necessary on airplanes changed as given in the original issue of this service bulletin. Continue to do repeat inspections as given in Revision 1 until the new dual structural glass pane windows are installed as given in Paragraph 1.E., Compliance. No airplanes were added to the service bulletin effectivity; however, airplanes line number 1418 and on were removed. **REASON FOR REVISION** This revision is sent to remove airplanes line number 1418 and on from the service bulletin effectivity and give terminating action for the requirements of continued inspection as given in this service bulletin. The inspections as given in this service bulletin are necessary on airplanes prior to line number 1418, which had single structural glass pane windows that can have cracks in the internal fail-safe interlayer. The inspections as given in this service bulletin are not necessary on airplanes line number 1418 and on, which have the new dual structural glass pane windows installed in production. The installation of the new dual structural glass pane windows as given in Revision 1 of this service bulletin is terminating action for the requirements of continued inspection as given in this service bulletin. These sections were changed: 1. Summary (Background and Action); Paragraph 1.C., Reason; and Paragraph 1.D., Description, were changed to clarify the difference between the single structural and dual structural glass pane windows. Correct names of different parts of the window assembly were added. Also added production incorporation information of the new dual structural glass pane window. 2. In Summary (Effectivity) and Paragraph 1.A., Effectivity, airplanes line number 1418 and on were removed. 3. In Summary (Compliance), added a reference to AD 2007-15-10. 4. In Paragraph 1.D., Description, a note in reference to sending inspection program and results was deleted.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 5 of 525. In Paragraph 1.E., Compliance, updated compliance tables to show conditions that affect the new dual structural glass pane windows, which is terminating action to the requirements of the continued inspection. Also added a reference to AD 2007-15-10. 6. In Paragraph 1.F., Approval, an Alternative Method of Compliance statement to the requirements of AD 2007-15-10 was added. 7. In Paragraph 1.G., Manpower, the words "single structural glass pane" were added to the No. 2 and No. 3 window inspection task. 8. In Paragraph 1.J.1., Existing Data, references were updated. 9. In Paragraph 1.K., Publications Affected, affected publications and damage tolerance evaluation statement were added. 10. In Paragraph 1.L., Interchangeability and Intermixability of Parts, statement was updated. 11. In Paragraph 2.C.2., Parts and Materials Supplied by the Operator, part information was updated. 12. In Paragraph 3.A., General Information, 747 minor models were removed from the reference to Structural Repair Manual, Chapter 51. Also added a note. 13. In Paragraph 3.B., Work Instructions, updated PART 1 and PART 2 instructions that affect the new dual structural glass pane windows. Added PART 3 to give window replacement instructions. 14. In Figure 1, notes were updated and added new dual structural glass pane window part numbers in the step table. 15. In Figure 2 and Figure 3, updated the step tables to add and clarify inspection requirements of the windows. Information Notice 747-56A2012 IN 01 and 02 were addressed. 16. In Summary Figure, Figure 2, and Figure 3, illustrations were updated to show text changes on part description. 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** August 24, 2006 Original Issue: August 12, 2010 Revision 1:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 6 of 52 **BOEING SERVICE BULLETIN 747-56A2012**

### Commercial **Airplanes** 

# 747 Service Bulletin **Summary Number: 747-56A2012**  Original Issue: August 24, 2006 Revision 1: August 12, 2010 ATA System: 5611 **SUBJECT:** WINDOWS - Flight Compartment - Flight Compartment Windows - Inspection of Glass No. 2 and No. 3 Windows for Cracks in the Fail-Safe Interlayer **CONCURRENT REQUIREMENTS** None. **BACKGROUND** Accomplishment of the inspection given in this service bulletin will make sure that no cracks are present in the internal fail-safe interlayer of the No. 2 and No. 3 windows that use a single structural glass pane. Fail-safe interlayer cracks can cause the affected windows to not be capable of carrying cabin pressurization loads if the structural glass pane of the window becomes broken. This could result in loss of a window and rapid loss of cabin pressure. Loss of a window can also cause crew communication difficulties or incapacitation of the crew. The left No. 2 and No. 3 windows are the pilot's side windows. The right No. 2 and No. 3 windows are the co-pilot's side windows. Affected airplanes may have No. 2 and No. 3 windows that are made from either acrylic or glass. The detailed inspections in this service bulletin are required only for glass windows that use a single structural glass pane to carry pressure loads. Airplanes prior to line number 1418 had single structural glass pane window, which can have cracks in the internal fail-safe interlayer. Windows that use dual structural glass panes or acrylic panes do not require inspections. Airplanes line number 1418 and on have No. 2 and No. 3 windows that use dual structural glass panes, which are installed in production. For airplanes prior to line number 1418, installation of the new dual structural glass pane windows is terminating action for the requirements of continued inspection as given in this service bulletin. There are two different, but interchangeable, designs for the No. 2 and No. 3 windows that use a single structural glass pane. The 65B27042-( ) and 65B27043-( ) windows consist of an outer glass pane and a structural inner glass pane, with a vinyl interlayer between them. The vinyl interlayer alone acts as the structural fail-safe load path if the structural inner glass pane becomes broken. The 65B27046-( ) and 65B27047-( ) windows consist of an outer glass pane and a structural inner glass pane, separated by an outboard urethane interlayer, a vinyl interlayer, and an inboard urethane interlayer. The vinyl and inboard urethane interlayers act as the structural fail-safe load path if the structural inner glass pane becomes broken.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 7 of 52One operator told Boeing that a glass No. 3 window with 36,131 flight-hours and 5,607 flight-cycles departed an airplane in-flight. Loss of the window resulted in rapid loss of cabin pressure, and an emergency landing was performed. Investigation revealed that a crack was present in the fail-safe interlayer of the 65B27043-2 single structural glass pane No. 3 window, along the inner edge of the window's aluminum edge insert. When the structural inner glass pane cracked due to an electrical arcing event not associated with the interlayer cracking, the interlayer was not able to support the airplane's cabin pressurization load and the window departed the airplane. The remaining single structural glass pane No. 3 window and both single structural glass pane No. 2 windows of this airplane were inspected, and all were found to have cracks in the fail-safe interlayer. Subsequent to this report, inspections accomplished by Boeing and some operators have found many additional instances of fail-safe interlayer cracks in 65B27042-( ) and 65B27043-( ) single structural glass pane No. 2 and No. 3 windows. In addition, several instances of inboard fail-safe interlayer cracks were found in 65B27046-( ) and 65B27047-( ) glass No. 2 and No. 3 windows. Interlayer cracks are primarily caused by thermal stress due to the different thermal expansion properties of the vinyl, glass, and window edging material. Moisture ingression into the window can also contribute to interlayer cracks. Accomplishment of the inspection in this service bulletin will ensure the structural integrity of the No. 2 and No. 3 windows that use a single structural glass pane. Boeing Service Related Problem (SRP) 747-SRP-56-0016 is related to this service bulletin. **ACTION (PRR 85901-85S)** Get internal access to the No. 2 and No. 3 windows on both the left and right sides of the airplane. Identify the windows (by part number) to determine if they are single structural glass pane, dual structural glass pane, or acrylic windows. No additional inspections are necessary on the following No. 2 and No. 3 windows, unless the windows are replaced with the single structural glass pane windows: – 65B07639-( ) or 65B07640-( ) acrylic windows – 141U4821-( ), 141U4831-( ), 141U4822-( ), or 141U4832-( ) dual structural glass pane windows Do a detailed inspection for cracks or damage, particularly in the internal interlayers for the following No. 2 and No. 3 windows that use single structural glass panes: 65B27042-( ), 65B27043-( ), 65B27046-( ), and 65B27047-( ). If no cracks or damage are found, do the inspection again at the time as given in this service bulletin. If any cracks or damage as given in this service bulletin are found, replace the affected window before any more flights. Do the inspection of all four windows again at the times as given in this service bulletin. **NOTE:**Color photographs of typical No. 2 and No. 3 window damage can be found in Fleet Team Digest Articles 747 FTD 56-05001 and 747-400 FTD 56-05001. These articles can be accessed through the MyBoeingFleet website, or you may obtain copies from your local Boeing Field Service office. As an alternative replace the single structural glass pane windows with dual structural glass pane windows. Installation of the dual structural glass pane windows is terminating action for the requirements of continued inspections as given in Paragraph 1.E., Compliance. Installation of the dual structural glass pane windows is necessary at the time as given in Paragraph 1.E., Compliance. **EFFECTIVITY** 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, and 747SR airplanes. See Service Bulletin Paragraph 1.A.1 for effectivity.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 8 of 52 **BOEING SERVICE BULLETIN 747-56A2012 COMPLIANCE**  See Service Bulletin Paragraph 1.E. for compliance information. Federal Aviation Administration (FAA) Airworthiness Directive AD 2007-15-10 is related to this service bulletin. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection or repair procedures given in this service bulletin. **MANPOWER Elapsed Hours**  **Total Task-Hours Task**  2.50 4.50 Window Identification and Inspection
**MATERIAL INFORMATION** Operator Supplied Parts. Refer to Paragraph 2.A., Material - Price and Availability.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 9 of 52 **BOEING SERVICE BULLETIN 747-56A2012**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 10 of 52 **BOEING SERVICE BULLETIN 747-56A2012**

### Commercial **Airplanes** 

# 747 Service Bulletin **Number: 747-56A2012** Original Issue: August 24, 2006 Revision 1: August 12, 2010 ATA System: 5611 **SUBJECT:** WINDOWS - Flight Compartment - Flight Compartment Windows - Inspection of Glass No. 2 and No. 3 Windows for Cracks in the Fail-Safe Interlayer **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes This service bulletin is for the airplanes shown below. An equivalent change is on subsequent production airplanes. Refer to PRR 85901-85S for data about this change. Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data.
**DESCRIPTION CONFIGURATION**  **GROUP** 747 airplanes line number 1 through 1417.

- 1

Airplane Models: 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, 747SR **Group Variable Number**  1 RA001 - RA034 1 RA101 - RA115 1 RA161 - RA164 1 RA201 - RA203 1 RA216 - RA217 1 RA245 - RA246 1 RA251 - RA266 1 RA301 - RA318 1 RA351 - RA360

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 11 of 52**Group Variable Number**  1 RA369 - RA373 1 RA401 - RA418 1 RA501 - RA502 1 RA521 - RA528 1 RA532 - RA548 1 RA551 - RA552 1 RA559 - RA561 1 RA581 - RA582 1 RA585 1 RA601 - RA602 1 RA631 - RA635 1 RA651 - RA652 1 RA671 - RA677 1 RA701 - RA702 1 RA721 - RA731 1 RA741 - RA745 1 RA749 - RA750 1 RA761 - RA762 1 RA781 - RA784 1 RA901 - RA916 1 RB001 - RB016 1 RB041 - RB044 1 RB071 - RB075 1 RB101 - RB102 1 RB411 - RB413 1 RB421 1 RB601 - RB607 1 RB681 - RB697 1 RB711 1 RB721 - RB723 1 RB741 - RB748 1 RD001 - RD004 1 RD021 - RD022

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 12 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RD041 - RD059 1 RD071 - RD072 1 RD081 - RD083 1 RD091 - RD092 1 RD101 - RD104 1 RD121 - RD127 1 RD131 - RD144 1 RD166 - RD167 1 RD171 - RD172 1 RD181 - RD183 1 RD201 - RD204 1 RD221 - RD227 1 RD231 - RD235 1 RD241 - RD243 1 RD251 - RD262 1 RD271 - RD272 1 RD291 - RD292 1 RD301 - RD302 1 RD311 1 RD351 - RD358 1 RD361 - RD366 1 RD381 - RD383 1 RD411 - RD414 1 RD421 - RD426 1 RD431 - RD435 1 RD441 - RD442 1 RD451 - RD456 1 RD461 1 RD471 - RD475 1 RD513 - RD519 1 RD531 - RD533 1 RD551 1 RD561

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 13 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RD571 1 RD581 - RD583 1 RD591 - RD593 1 RD601 - RD607 1 RD621 - RD623 1 RD641 - RD649 1 RD651 - RD659 1 RD661 1 RD671 1 RD681 - RD682 1 RD691 - RD692 1 RD701 - RD702 1 RD721 - RD722 1 RD741 - RD742 1 RD751 - RD755 1 RD761 1 RD771 - RD775 1 RD781 - RD783 1 RD791 - RD792 1 RE001 1 RF001 - RF006 1 RG001 - RG009 1 RG091 1 RG095 1 RG101 - RG104 1 RG121 - RG126 1 RG141 - RG142 1 RG161 - RG164 1 RG171 - RG174 1 RG191 - RG193 1 RG211 - RG213 1 RG221 - RG222 1 RH101 - RH102

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 14 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RH111 - RH112 1 RH121 - RH122 1 RJ131 - RJ133 1 RJ151 - RJ152 1 RJ301 - RJ303 1 RJ321 - RJ322 1 RJ331 - RJ333 1 RL401 - RL403 1 RL411 - RL436 1 RL451 - RL456 1 RL461 - RL462 1 RL471 - RL479 1 RL481 1 RL491 - RL492 1 RL501 - RL502 1 RL511 - RL516 1 RL521 - RL522 1 RL531 - RL534 1 RL551 1 RL561 - RL568 1 RL571 1 RL576 - RL577 1 RL579 1 RL581 - RL586 1 RL651 - RL655 1 RL671 - RL675 1 RL681 - RL684 1 RL751 - RL752 1 RM001 - RM007 1 RM010 - RM013 1 RM021 - RM024 1 RM026 - RM030 1 RM036 - RM045

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 15 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RM051 - RM053 1 RM071 1 RM081 - RM084 1 RM091 1 RM096 - RM097 1 RM116 - RM117 1 RM126 - RM132 1 RM136 - RM147 1 RM156 - RM158 1 RM166 - RM177 1 RM191 - RM192 1 RM231 - RM233 1 RM241 - RM246 1 RM261 - RM264 1 RM316 - RM318 1 RM331 - RM333 1 RM341 1 RM351 - RM355 1 RM366 - RM367 1 RM401 - RM403 1 RM426 1 RM431 1 RM441 - RM443 1 RM445 1 RM801 - RM803 1 RM811 - RM813 1 RM851 - RM859 1 RM861 - RM863 1 RM871 - RM899 1 RM901 - RM906 1 RM911 1 RR001 - RR005 1 RR021 - RR025

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 16 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RR031 1 RR201 - RR206 1 RR221 - RR226 1 RR261 - RR267 1 RR301 - RR310 1 RR331 - RR332 1 RR336 1 RR341 - RR345 1 RR361 - RR362 1 RR421 - RR422 1 RR431 - RR432 1 RR441 - RR442 1 RR451 1 RR501 - RR504 1 RR521 - RR522 1 RR526 1 RR531 1 RR551 - RR556 1 RR561 1 RR566 1 RR701 1 RR721 - RR724 1 RR746 - RR748 1 RR851 - RR856 1 RR861 - RR862 1 RR951 - RR952 1 RS001 - RS002 1 RS201 1 RS211 - RS212 1 RS221 - RS222 1 RS231 - RS241 1 RS251 - RS259 1 RS263

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 17 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RS265 - RS268 1 RS271 - RS276 1 RS291 - RS292 1 RS301 - RS306 1 RS311 - RS320 1 RS331 - RS333 1 RS341 - RS342 1 RS699 1 RS701 - RS703 1 RS711 - RS713 1 RS721 - RS722 1 RS731 - RS732 1 RS741 - RS743 1 RS751 - RS752 1 RS761 - RS762 1 RS771 1 RS781 - RS782 1 RS786 1 RT001 - RT014 1 RT021 - RT022 1 RT031 - RT035 1 RT041 - RT047 1 RT061 1 RT071 - RT075 1 RT101 - RT103 1 RT121 1 RT131 - RT137 1 RT151 - RT152 1 RT161 - RT168 1 RT401 - RT412 1 RT431 - RT447 1 RT451 - RT469 1 RT471 - RT499

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 18 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Group**  **Variable Number** 1 RT501 - RT535 1 RT551 - RT568 1 RT571 - RT591 1 RT601 - RT657 1 RT671 - RT673 1 RT681 - RT682 1 RT691 - RT699 1 RT701 - RT704 1 RT711 - RT717 1 RT741 - RT757 1 RT776 - RT777 1 RT781 - RT784 1 RT801 - RT803 1 RT811 - RT814 1 RT831 - RT837 1 RT861 - RT864 1 RT876 - RT880 1 RT931 - RT932 1 RT945 - RT949 1 RT951 - RT955 1 RT966 - RT967 1 RU001 - RU006 1 RU016 - RU017 1 RU031 - RU032 1 RU051 - RU052 1 RU059 - RU062 1 RU081 - RU083 1 RU101 - RU102 1 RU121 - RU132 1 RU801 - RU809 1 RU831 - RU841

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 19 of 52 **BOEING SERVICE BULLETIN 747-56A2012**2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** Accomplishment of the inspection given in this service bulletin will make sure that no cracks are present in the internal fail-safe interlayer of the No. 2 and No. 3 windows that use a single structural glass pane. Fail-safe interlayer cracks can cause the affected windows to not be capable of carrying cabin pressurization loads if the structural glass pane of the window becomes broken. This could result in loss of a window and rapid loss of cabin pressure. Loss of a window can also cause crew communication difficulties or incapacitation of the crew. The left No. 2 and No. 3 windows are the pilot's side windows. The right No. 2 and No. 3 windows are the co-pilot's side windows. Affected airplanes may have No. 2 and No. 3 windows that are made from either acrylic or glass. The detailed inspections in this service bulletin are required only for glass windows that use a single structural glass pane to carry pressure loads. Airplanes prior to line number 1418 had single structural glass pane window, which can have cracks in the internal fail-safe interlayer. Windows that use dual structural glass panes or acrylic panes do not require inspections. Airplanes line number 1418 and on have No. 2 and No. 3 windows that use dual structural glass panes, which are installed in production. For airplanes prior to line number 1418, installation of the new dual structural glass pane windows is terminating action for the requirements of continued inspection as given in this service bulletin. There are two different, but interchangeable, designs for the No. 2 and No. 3 windows that use a single structural glass pane: — The 65B27042-( ) and 65B27043-( ) windows consist of an outer glass pane and a structural inner glass pane, with a vinyl interlayer between them. The vinyl interlayer alone acts as the structural fail-safe load path if the structural inner glass pane becomes broken. — The 65B27046-( ) and 65B27047-( ) windows consist of an outer glass pane and a structural inner glass pane, separated by an outboard urethane interlayer, a vinyl interlayer, and an inboard urethane interlayer. The vinyl and inboard urethane interlayers act as the structural fail-safe load path if the structural inner glass pane becomes broken. In No. 2 and No. 3 windows that use dual structural glass panes or acrylic panes, the second pane, not vinyl interlayer, acts as the structural fail-safe element. One operator told Boeing that a glass No. 3 window with 36,131 flight-hours and 5,607 flight-cycles departed an airplane in-flight. Loss of the window resulted in rapid loss of cabin pressure, and an emergency landing was performed. Investigation revealed that a crack was present in the fail-safe interlayer of the 65B27043-2 single structural glass pane No. 3 window, along the inner edge of the window's aluminum edge insert. When the structural inner glass pane cracked due to an electrical arcing event not associated with the interlayer cracking, the interlayer was not able to support the airplane's cabin pressurization load and the window departed the airplane. The remaining single structural glass pane No. 3 window and both single structural glass pane No. 2 windows of this airplane were inspected, and all were found to have cracks in the fail-safe interlayer.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 20 of 52 **BOEING SERVICE BULLETIN 747-56A2012**Subsequent to this report, inspections accomplished by Boeing and some operators have found many additional instances of fail-safe interlayer cracks in 65B27042-( ) and 65B27043-( ) single structural glass pane No. 2 and No. 3 windows. In addition, several instances of inboard fail-safe interlayer cracks were found in 65B27046-( ) and 65B27047-( ) single structural glass pane No. 2 and No. 3 windows. Interlayer cracks are primarily caused by thermal stress due to the different thermal expansion properties of the vinyl, glass, and window edging material. Moisture ingression into the window can also contribute to interlayer cracks. Accomplishment of the inspection in this service bulletin will ensure the structural integrity of the No. 2 and No. 3 windows that use a single structural glass pane. Revision 1 is sent to remove airplanes line number 1418 and on from the service bulletin effectivity and give terminating action for the requirements of continued inspection as given in this service bulletin. The inspections as given in this service bulletin are necessary on airplanes prior to line number 1418, which had single structural glass pane windows that can have cracks in the internal fail-safe interlayer. The inspections as given in this service bulletin are not necessary on airplanes line number 1418 and on, which have the new dual structural glass pane windows installed in production. The installation of the new dual structural glass pane windows as given in Revision 1 of this service bulletin is terminating action for the requirements of continued inspection as given in this service bulletin. These sections were changed: 1. Summary (Background and Action); Paragraph 1.C., Reason; and Paragraph 1.D., Description, were changed to clarify the difference between the single structural and dual structural glass pane windows. Correct names of different parts of the window assembly were added. Also added production incorporation information of the new dual structural glass pane window. 2. In Summary (Effectivity) and Paragraph 1.A., Effectivity, airplanes line number 1418 and on were removed. 3. In Summary (Compliance), added a reference to AD 2007-15-10. 4. In Paragraph 1.D., Description, a note in reference to sending inspection program and results was deleted. 5. In Paragraph 1.E., Compliance, updated compliance tables to show conditions that affect the new dual structural glass pane windows, which is terminating action to the requirements of the continued inspection. Also added a reference to AD 2007-15-10. 6. In Paragraph 1.F., Approval, an Alternative Method of Compliance statement to the requirements of AD 2007-15-10 was added. 7. In Paragraph 1.G., Manpower, the words "single structural glass pane" were added to the No. 2 and No. 3 window inspection task. 8. In Paragraph 1.J.1., Existing Data, references were updated. 9. In Paragraph 1.K., Publications Affected, affected publications and damage tolerance evaluation statement were added. 10. In Paragraph 1.L., Interchangeability and Intermixability of Parts, statement was updated.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 21 of 52 **BOEING SERVICE BULLETIN 747-56A2012**11. In Paragraph 2.C.2., Parts and Materials Supplied by the Operator, part information was updated. 12. In Paragraph 3.A., General Information, 747 minor models were removed from the reference to Structural Repair Manual, Chapter 51. Also added a note. 13. In Paragraph 3.B., Work Instructions, updated PART 1 and PART 2 instructions that affect the new dual structural glass pane windows. Added PART 3 to give window replacement instructions. 14. In Figure 1, notes were updated and added new dual structural glass pane window part numbers in the step table. 15. In Figure 2 and Figure 3, updated the step tables to add and clarify inspection requirements of the windows. Information Notice 747-56A2012 IN 01 and 02 were addressed. 16. In Summary Figure, Figure 2, and Figure 3, illustrations were updated to show text changes on part description. Boeing Service Related Problem (SRP) 747-SRP-56-0016 is related to this service bulletin. **D. Description** Get internal access to the No. 2 and No. 3 windows on both the left and right sides of the airplane. Identify the windows (by part number) to determine if they are single structural glass pane, dual structural glass pane, or acrylic windows. No additional inspections are necessary on the following No. 2 and No. 3 windows, unless the windows are replaced with the single structural glass pane windows: – 65B07639-( ) or 65B07640-( ) acrylic windows – 141U4821-( ), 141U4831-( ), 141U4822-( ), or 141U4832-( ) dual structural glass pane windows Do a detailed inspection for cracks or damage, particularly in the internal interlayers for the following No. 2 and No. 3 windows that use single structural glass panes: 65B27042-( ), 65B27043-( ), 65B27046-( ), and 65B27047-( ). If no cracks or damage are found, do the inspection again at the time as given in this service bulletin. If any cracks or damage as given in this service bulletin are found, replace the affected window before any more flights. Do the inspection of all four windows again at the times as given in this service bulletin. **NOTE:**Color photographs of typical No. 2 and No. 3 window damage can be found in Fleet Team Digest Articles 747 FTD 56-05001 and 747-400 FTD 56-05001. These articles can be accessed through the MyBoeingFleet website, or you may obtain copies from your local Boeing Field Service office. As an alternative replace the single structural glass pane windows with dual structural glass pane windows. Installation of the dual structural glass pane windows is terminating action for the requirements of continued inspections as given in Paragraph 1.E., Compliance. Installation of the dual structural glass pane windows is necessary at the time as given in Paragraph 1.E., Compliance. Revision 1 - No more work is necessary on airplanes changed as given in the original issue of this service bulletin. Continue to do repeat inspections as given in Revision 1 until the new dual structural glass pane windows are installed as given in Paragraph 1.E., Compliance. The work in this service bulletin is done in the maintenance zone(s) given below.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 22 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Affected Maintenance Zones** **Zone Model**  221, 222 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SP, 747SR **E. Compliance Table 1: No. 2 and No. 3 Window Identification**  **Compliance Time (Whichever Occurs First) Action**  **Condition** Within 2 years after the original issue date of this service bulletin. Within 5,500 flight-hours after the window was installed or 1,000 flight-hours after theoriginal issue date of this service bulletin, whichever occurs later. (b) Do Window Identification as given in PART 1 of Paragraph 3.B., Work Instructions. (a) All airplanes

Refer to Table 2 Refer to Table 2 Do detailed inspections as shown in Table 2. 65B27042-( ) or 65B27043-( ) single structural glass panewindows found or installed Refer to Table 3 Refer to Table 3 Do detailed inspections as shown in Table 3. 65B27046-( ) or 65B27047-( ) single structural glass panewindows found or installed

- - No further action required for that window position. (c) 65B07639-( ) or 65B07640-( ) acrylicwindows found or installed

- - No further action required for that window position. (c) 141U4821-( ), 141U4822-( ), 141U4831-( ), or141U4832-( ) dual structural glass pane windows found or installed (a) Instead of inspecting the windows for identification, a review of maintenance records is acceptable if the part number of the window can be positively determined from that review. (b) If the number of flight-hours since the window was installed is not known, you must assume that the window is beyond the 5,500 flight-hour limit. (c) If the window is later replaced, refer to the applicable condition in this table for subsequent inspection requirements of the replacement window.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 23 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Table 2: Detailed Inspections for 65B27042-( ) and 65B27043-( ) Single Structural Glass Pane No. 2 and**  **No. 3 Windows Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever Occurs**  **First) Action**  **Condition**

- Within 2 yearsafter the original issue date of this service bulletin. Within 5,500 flight-hoursafter the window was installed or 1,000 flight-hours after the original issue date of this service bulletin, whichever occurs later. (a) Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27042-( ) or65B27043-( ) Single Structural Glass Pane No. 2and No. 3 Windows. AND

- Within 6 years of the Revision 1 date of this service bulletin. Replace the window with 141U4821-( ), 141U4822- ( ), 141U4831-( ), and/or141U4832-( ) dual structural glass pane windows as given in PART 3 ofParagraph 3.B., Work Instructions.

- - No further action required for that window position. (c) (d) 141U4821-( ), 141U4822-( ), 141U4831-( ), and/or 141U4832- ( ) dual structuralglass pane replacement windows installed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 24 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Table 2: Detailed Inspections for 65B27042-( ) and 65B27043-( ) Single Structural Glass Pane No. 2 and**  **No. 3 Windows Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever Occurs**  **First) Action**  **Condition** 3,000 flight-hours or 3 years, whichever occurs first. Within 3,000 flight-hours or 3 years of the initial inspection, whichever occurs first. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) No window cracks or damage found.

- Before further flight. Replace the window asgiven in PART 3 of Paragraph 3.B., Work Instructions. (c) Window cracks or damage found.

3,000 flight-hours or 3 years, whichever occurs first. Within 5,500 flight-hours after the window was installed. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27042-( ) and/or 65B27043-( ) single structural glass panereplacement windows that are new or have zero flight hours. 3,000 flight-hours or 3 years, whichever occurs first. Before installation. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27042-( ) and/or 65B27043-( ) single structural glass panereplacement windows that are notnew or have unknown flight hours. 7,500 flight-hours or 5 years, whichever occurs first. Within 22,000 flight-hours after the window was installed. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27046-( ) and/or 65B27047-( ) single structural glass panereplacement windows that are new or have zero flight hours. 7,500 flight-hours or 5 years, whichever occurs first. Before installation. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27046-( ) and/or 65B27047-( ) single structural glass panereplacement windows that are notnew or have unknown flight hours.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 25 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Table 2: Detailed Inspections for 65B27042-( ) and 65B27043-( ) Single Structural Glass Pane No. 2 and**  **No. 3 Windows Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever Occurs**  **First) Action**  **Condition** (a) If the number of flight-hours since the window was installed is not known, you must assume that the window is beyond the 5,500 flight-hour limit. (b) The detailed inspection of single structural glass pane windows is only applicable within 6 years after the Revision 1 date of this service bulletin. (c) Installation of 141U4821-( ), 141U4822-( ), 141U4831-( ), and/or 141U4832-( ) dual structural glass pane windows is terminating action for the continued inspections as given in this service bulletin and is necessary within 6 years after the Revision 1 date of this service bulletin. (d) If the window is later replaced, refer to the applicable condition in this table for subsequent inspection requirements of the replacement window. **Table 3: Detailed Inspections for 65B27046-( ) and 65B27047-( ) Single Structural Glass Pane No. 2 and No. 3 Windows**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs First)**  **Action Condition** 

- Within 3 yearsafter the original issue date of this service bulletin. Within 22,000 flight-hoursafter the window was installed or 1,000 flighthours after the original issue date of this service bulletin, whichever occurs later. (a) Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27046-( ) or65B27047-( ) Single Structural Glass Pane No. 2and No. 3 Windows.
AND

- Within 6 years of the Revision 1 date of this service bulletin. Replace the window with 141U4821-( ), 141U4822- ( ), 141U4831-( ), and/or141U4832-( ) dual structural glass pane windows as given in PART 3 ofParagraph 3.B., Work Instructions.

- - No further action required for that window position. (c) (d) 141U4821-( ), 141U4822-( ), 141U4831-( ), and/or 141U4832- ( ) dual structuralglass pane replacement windows installed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 26 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Table 3: Detailed Inspections for 65B27046-( ) and 65B27047-( ) Single Structural Glass Pane No. 2 and**  **No. 3 Windows Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever Occurs**  **First) Action**  **Condition** 7,500 flight-hours or 5 years, whichever occurs first. Within 7,500 flight-hours or 5 years of the initial inspection, whichever occurs first. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) No window cracks or damage found.

- Before further flight. Replace the window asgiven in PART 3 of Paragraph 3.B., Work Instructions. (c) Window cracks or damage found.

3,000 flight-hours or 3 years, whichever occurs first. Within 5,500 flight-hours after the window was installed. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27042-( ) and/or 65B27043-( ) single structural glass panereplacement windows that are new or have zero flight hours. 3,000 flight-hours or 3 years, whichever occurs first. Before installation. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27042-( ) and/or 65B27043-( ) single structural glass panereplacement windows that are notnew or have unknown flight hours. 7,500 flight-hours or 5 years, whichever occurs first. Within 22,000 flight-hours after the window was installed. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27046-( ) and/or 65B27047-( ) single structural glass panereplacement windows that are new or have zero flight hours. 7,500 flight-hours or 5 years, whichever occurs first. Before installation. Do a detailed inspection of the windows as given in PART 2 of Paragraph 3.B., Work Instructions. (b) (c) 65B27046-( ) and/or 65B27047-( ) single structural glass panereplacement windows that are notnew or have unknown flight hours.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 27 of 52 **BOEING SERVICE BULLETIN 747-56A2012 Table 3: Detailed Inspections for 65B27046-( ) and 65B27047-( ) Single Structural Glass Pane No. 2 and**  **No. 3 Windows Repeat Interval**  **(Not to Exceed) Compliance Time (Whichever Occurs**  **First) Action**  **Condition** (a) If the number of flight-hours since the window was installed is not known, you must assume that the window is beyond the 22,000 flight-hour limit. (b) The detailed inspection of single structural glass pane windows is only applicable within 6 years after the Revision 1 date of this service bulletin. (c) Installation of 141U4821-( ), 141U4822-( ), 141U4831-( ), and/or 141U4832-( ) dual structural glass panewindows is terminating action for the continued inspections as given in this service bulletin and is necessary within 6 years after the Revision 1 date of this service bulletin. (d) If the window is later replaced, refer to the applicable condition in this table for subsequent inspection requirements of the replacement window. Federal Aviation Administration (FAA) Airworthiness Directive AD 2007-15-10 is related to this service bulletin. **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. The Manager of the FAA Seattle Aircraft Certification office (ACO) approves the applicability under paragraph 1.A., "Effectivity" of Service Bulletin 747-56A2012, Revision 1, as an AMOC to the applicability required by paragraph (c) of AD 2007-15-10. In addition, the Manager of the FAA Seattle ACO approves the inspections, investigative and corrective actions with the corresponding compliance times specified in Tables 1 through 3, under paragraph 1.E., “Compliance," of Service Bulletin 747-56A2012, Revision 1, as an AMOC to the inspection, investigative and corrective actions with the corresponding compliance times specified in Table 1 through 3, under paragraph 1.E., “Compliance," of Service Bulletin 747-56A2012, dated August 24, 2006, required by paragraphs (f) and (g) of AD 2007-15-10. When this service bulletin specifies contacting Boeing for repair instructions, the repair instructions must be approved by the FAA in accordance with paragraph (h) of the AD. All provisions of AD 2007-15-10 that are not specifically referenced in this paragraph remain fully applicable and must be complied with. **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:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 28 of 52 **BOEING SERVICE BULLETIN 747-56A2012**— Time to adjust to the workplace — Time to schedule the work — Time to examine the work — Time to cure the materials — Time to make the parts — Time to find the tools. **Elapsed Hours Task-Hours**  **Number of Persons**  **Task**
0.25 0.25 1 Open Access 1.75 3.50 2 Identify the No. 2 and No. 3 Windows, Left and Right (Figure 1) 0.25 0.50 2 Inspect the Single Structural Glass Pane No. 2 and No. 3 Windows, Left and Right (Figure 2 or Figure 3) 0.25 0.25 1 Close Access 2.50 4.50 TOTAL FOR EACH AIRPLANE
**NOTE:**More time will be required for window replacement if damage is found. **H. Weight and Balance Changes** None. **I. Electrical Load Data** 747-400: Not changed. All other 747: Not applicable. **J. References** 1. Existing Data: a. Service Related Problem (SRP) 747-SRP-56-0016 b. Engineering Change Memo PRR 85901-85S c. Federal Aviation Administration (FAA) Airworthiness Directive AD 2007-15-10 d. 747-100/200/300 Aircraft Maintenance Manual (AMM) 25-13-03, 25-15-02, 56-11-00, 56-11-02 e. 747-400 Aircraft Maintenance Manual (AMM) 25-13-03, 25-15-02, 56-11-00, 56-11-02 2. Data supplied with this Service Bulletin: None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 29 of 52 **BOEING SERVICE BULLETIN 747-56A2012**3. Installation Drawings Used in the Preparation of this Service Bulletin:
**Title Drawing Number**  Window Instl - Control Cab No. 2 141U0001 Window Instl - Control Cab No. 3 141U0002 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. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  56-11 747-100/200/300 Illustrated Parts Catalog56-11 747-400 Illustrated Parts Catalog 56-11 747-400LCF Illustrated Parts Catalog 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 does not affect FCS, therefore DTIs are not necessary. **L. Interchangeability and Intermixability of Parts** Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 30 of 52 **BOEING SERVICE BULLETIN 747-56A2012 2. MATERIAL INFORMATION**  **A. Material - Price and Availability** The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary For Each Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. **B. Industry Support Information** Boeing warranty remedies are not available for the inspection 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:
**Notes Existing Part Number**  **(b) (c) Name**  **QTY Part Number**  **(a)**

- 65B27042-1 or 65B27046- 1 Glass No. 2 Window Assembly - Left Side (Manufactured by GKN) 1 141U4821-11

- 65B27042-1 or 65B27046- 1 Glass No. 2 Window Assembly - Left Side (Manufactured by PPG) 1 141U4822-11

- 65B27042-2 or 65B27046- 2 Glass No. 2 Window Assembly - Right Side (Manufactured by GKN) 1 141U4821-12

- 65B27042-2 or 65B27046- 2 Glass No. 2 Window Assembly - Right Side (Manufactured by PPG) 1 141U4822-12

- 65B27043-1 or 65B27047- 1 Glass No. 3 Window Assembly - Left Side (Manufactured by GKN) 1 141U4831-1

- 65B27043-1 or 65B27047- 1 Glass No. 3 Window Assembly - Left Side (Manufactured by PPG) 1 141U4832-11

- 65B27043-2 or 65B27047- 2 Glass No. 3 Window Assembly - Right Side (Manufactured by GKN) 1 141U4831-2

- 65B27043-2 or 65B27047- 2 Glass No. 3 Window Assembly - Right Side (Manufactured by PPG) 1 141U4832-12 (a) This new part is used in production. The installation of the new part is necessary at the time as given in Paragraph 1.E., Compliance. (b) You can not use the existing part to replace the new part. (c) You can continue to use the existing part until the time as given in Paragraph 1.E., Compliance. If you use the existing part, repeat inspections are necessary at the times as given Paragraph 1.E., Compliance.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 31 of 52 **BOEING SERVICE BULLETIN 747-56A2012**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. Examine operator tool supply to make sure all necessary tools are available.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 32 of 52 **BOEING SERVICE BULLETIN 747-56A2012 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. — Angular tolerance is plus or minus 2 degrees — Torque limits to tighten nuts and bolts are given in 747 Structural Repair Manual, Chapter 51. 4. 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. 5. If the inspection is to be done in bright daylight conditions, Boeing recommends use of a high power LED flashlight to find fail-safe interlayer cracks. 6. These work instructions refer to procedures included on 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 "as given in" are included in the instruction, the procedure in the Boeing document must be used. 7. To avoid unscheduled removal of the airplane from service for window replacement, Boeing recommends that operators have replacement window assemblies available before window inspections begin. 8. This service bulletin contains instructions to remove and keep parts for installation. However, before installation of any removed and kept part, the part must be in a serviceable condition. Replacement of the removed and kept part with a new or serviceable part of the same part number/specification is an acceptable alternative unless otherwise stated in the service bulletin instructions.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 33 of 52 **BOEING SERVICE BULLETIN 747-56A2012 B. WORK INSTRUCTIONS**  **PART 1 - WINDOW IDENTIFICATION** 1. Get internal access to the flight deck windows and identify the No. 2 and No. 3 windows as given in Figure 1. 2. If any of the following windows are found or installed, put the airplane back to a serviceable condition: – 65B07639-( ) or 65B07640-( ) acrylic windows – 141U4821-( ), 141U4822-( ), 141U4831-( ), or 141U4832-( ) dual structural glass pane windows No additional inspections are required on these windows. 3. If any glass 65B27042-( ), 65B27043-( ), 65B27046-( ), or 65B27047-( ) windows are found or installed, put the airplane back to a serviceable condition. **PART 2 - WINDOW INSPECTION** 1. Get internal access and prepare to inspect the No. 2 and No. 3 flight deck windows. Refer to 747-100/200/300 AMM 56-11-00 or 747-400 AMM 56-11-00 as an accepted procedure. **NOTE:**If internal inspections are not adequate to determine the condition of the windows, also do external inspections. 2. Do a detailed inspection of 65B27042-( ) and 65B27043-( ) single structural glass pane No. 2 and No. 3 windows (left and right sides) as given in Figure 2. 3. Do a detailed inspection of 65B27046-( ) and 65B27047-( ) single structural glass pane No. 2 and No. 3 windows (left and right sides) as given in Figure 3. 4. If any of the following cracks or damage are found, replace the affected window as given in PART 3: a. The window has cracks in any fail-safe interlayer. b. The window has cracks in a glass pane. c. The window has chips in a structural glass pane. d. The window shows any indications of arcing. Arcing usually occurs near the window bus bars. Heat damage caused by arcing can be identified by brown or black burn marks in the internal interlayer. e. The window has any non-clear damage. Non-clear damage may indicate a degradation of the structural capability of the window and may hinder inspection for other damage such as fail-safe interlayer cracks or electrical arcing. 5. If no cracks or damage are found, put the airplane back to a serviceable condition. Do the inspections as given in PART 2 again at the times as given in Paragraph 1.E., Compliance.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 34 of 52 **BOEING SERVICE BULLETIN 747-56A2012 NOTE:** As an alternative to repeat inspections, replace the single structural glass pane windows with the dual structural glass pane windows as given in PART 3. Installation of the dual structural glass pane windows is terminating action for the requirements of continued inspection as given in this service bulletin and necessary at the time as given in Paragraph 1.E., Compliance. **PART 3 - WINDOW REPLACEMENT** 1. Option 1: a. Replace single structural glass pane No. 2 and/or No. 3 windows with 65B27042-( ), 65B27043-( ), 65B27046-( ) and/or 65B27047-( ) single structural glass pane No. 2. and/or No. 3 windows as applicable. Refer to 747-100/200/300 AMM 56-11-02 or 747-400 AMM 56-11-02 as an accepted procedure for the window replacement. **NOTE:**65B27042-( ) and 65B27046-( ) single structural glass pane No. 2. windows are interchangeable. 65B27043-( ) and 65B27047-( ) single structural glass pane No. 3. windows are interchangeable. b. Do the inspections given in PART 2 again at the times as given in Paragraph 1.E., Compliance. 2. Option 2: a. Replace 65B27042-( ) and/or 65B27046-( ) single structural glass pane No. 2 windows with 141U4821-( ) and/or 141U4822-( ) dual structural glass pane No. 2 windows. Refer to 747-100/200/300 AMM 56-11-02 or 747-400 AMM 56-11-02 as an accepted procedure for the window replacement. b. Replace 65B27043-( ) and/or 65B27047-( ) single structural glass pane No. 3 windows with 141U4831-( ) and/or 141U4832-( ) dual structural glass pane No. 3 windows. Refer to 747-100/200/300 AMM 56-11-02 or 747-400 AMM 56-11-02 as an accepted procedure for the window replacement. c. No more inspections are necessary as given in this service bulletin for the dual structural glass pane No. 2 and No. 3 windows. 3. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1: August 12, 2010 35 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 1: NO. 2 AND NO. 3 WINDOW IDENTIFICATION**  **(SHEET 1 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 36 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 1: NO. 2 AND NO. 3 WINDOW IDENTIFICATION**  **(SHEET 2 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 37 of 52 **BOEING SERVICE BULLETIN 747-56A2012**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each airplane. **NOTE:** The window part number can be found on the manufacturer's nameplate, which should be located along the upper edge of the window, on the inboard surface of the window or window edging. 1.

2. If the window part number cannot be found, the following may be used to help distinguish between the different windows: — Acrylic windows (Part Number 65B07639-( ) and 65B07640-( ) ) do not have a window edging or metal insert as is found on the single structural glass pane windows (Part Number 65B027042-( ), 65B27043-( ), 65B27046-( ), and 65B27046-( ) ) and dual structural glass pane windows (Part Number 141U4821-( ), 141U4822-( ), 141U4831-(), and 141U4832-( ) ). — Dual structural glass pane windows have wire grid temperature sensors embedded in the interlayer between glass panes. For No. 2 windows, these sensors are located along the forward edge; and for No. 3 windows, these sensors are located along the aft edge. — On acrylic windows, one of the thermal sensors is recessed into the inner ply. On single and dual structural glass pane windows, both thermal sensors are surface mounted. — On single and dual structural glass pane windows, there will be a small surface mounted plastic ring around one of the thermal sensors to hold it in place. The plastic ring is not used on acrylic windows. — The 65B27042-( ) and 65B27043-( ) single structural glass pane windows have internal tape that is visible around the periphery of the window. The internal tape is nearly transparent, but may include visible wrinkles, particularly in the corners of the windows. The internal tape does not exist on; 65B27046-( ) and 65B27047-( ) single structural glass pane windows; 65B07639-( ) and 65B07640-( ) acrylic windows; 141U4821-( ), 141U4822-(), 141U4831-( ), and 141U4832-( ) dual structural glass pane windows.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Refer to 747-100/200/300 AMM 25-15-02 or 747-400 AMM 25-15-02 as accepted procedures. 4
- Crash Pads Remove / Keep 1

Refer to 747-100/200/300 AMM 25-13-03 or 747-400 AMM 25-13-03 as accepted procedures. 2
- Visor Track Remove / Keep 2

- 2
- No. 3 Window Sun- shade Remove / Keep 3 Common to the No. 1, No. 2, and No. 3 windows. 2
- Upper Molding Remove / Keep 4

- 2
- Sidewall Lining Remove / Keep 5

**FIGURE 1: NO. 2 AND NO. 3 WINDOW IDENTIFICATION (SHEET 3 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 38 of 52 **BOEING SERVICE BULLETIN 747-56A2012 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** of Left No. 3 Window 1 65B27043-1 or 65B27047-1 or 65B07640-1 or 65B07640-19 or 141U4831-1 or 141U4832-11 (a) Part Number Record 6

of Left No. 2 Window 1 65B27042-1 or 65B27046-1 or 65B07639-1 or 65B07639-19 or 141U4821-11 or 141U4822-11 (b) Part Number Record 7

of Right No. 2 Window 1 65B27042-2 or 65B27046-2 or 65B07639-2 or 65B07639-20 or 141U4821-12 or 141U4822-12 (c) Part Number Record 8

of Right No. 3 Window 1 65B27043-2 or 65B27047-2 or 65B07640-2 or 65B07640-20 or 141U4831-2 or 141U4832-12 (d) Part Number Record 9

- 2
- Sidewall Lining (Kept) Install 10

- 2
- Upper Molding (Kept) Install 11

- 2
- No. 3 Window Sun- shade (Kept) Install 12
Refer to 747-100/200/300 AMM 25-13-03 or 747-400 AMM 25-13-03 as accepted procedures. 2
- Visor Track (Kept) Install 13

Refer to 747-100/200/300 AMM 25-15-02 or 747-400 AMM 25-15-02 as accepted procedures. 4
- Crash Pads (Kept) Install 14

(a) If the window cannot be identified, assume the part number is 65B27043-1. (b) If the window cannot be identified, assume the part number is 65B27042-1. (c) If the window cannot be identified, assume the part number is 65B27042-2. (d) If the window cannot be identified, assume the part number is 65B27043-2.

**FIGURE 1: NO. 2 AND NO. 3 WINDOW IDENTIFICATION (SHEET 4 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 39 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 1 OF 6)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 40 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 2 OF 6)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 41 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 3 OF 6)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 42 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 4 OF 6)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 43 of 52 **BOEING SERVICE BULLETIN 747-56A2012**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c) (d) 1
- Left No. 3 Window Inspect 1

**FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW DETAILED INSPECTION**  **(SHEET 5 OF 6)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 44 of 52 **BOEING SERVICE BULLETIN 747-56A2012 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) (b) (c) (d) 1
- Left No. 2 Window Inspect 2 (a) (b) (c) (d) 1
- Right No. 2 Window Inspect 3 (a) (b) (c) (d) 1
- Right No. 3 Window Inspect 4 (a) Do an internal detailed inspection of the flight deck window for the following cracks or damage: fail-safe interlayer cracks, glass pane cracks and chips, and indications of arcing. An optional external detailed inspection of the flight deck window for the damage may be necessary if the existing window conditions do not allow complete inspection from the inside of the flight deck. Any non-clear damage should be noted that may hinder inspection of the damage. (b) Inspect the window for vinyl fail-safe interlayer cracks along the metal edge insert and along the edge of the release tape. Vinyl fail-safe interlayer cracks can be at any location in the window, but are usually found along the metal edge insert and along the edge of the release tape. (c) Inspect the window for glass pane cracks and chips. There are many types of chips but pay particular attention to "V" shaped chips and peel chips. "V" shaped chips occur on the external surface of the glass pane and have a sharp narrow "V" where the depth is equal to or larger than the width. Peel chips occur on the internal surface of the glass pane and these areas have a curved, rough grained shape, and are easily seen in reflected light. The area of the peel chips can have small glass flakes, usually white, and view through the window will distort through the rough surface of the chip. Peel chips start very small but can continue to grow with the continued use of the airplane. (d) Inspect the window for any indications of arcing. An arc can occur due to an electrical discharge or short circuit across a wire, bus bar, conductive heating film or other internal window components. Arcs usually occur near the window bus bars, and are typically the result of moisture ingress. The heat from an arc can cause dark brown or black burn marks on the bus bar and in the interlayer. Arcs in the heating film away from the bus bar can occur as a jagged line. The flag note number shown below agrees with the number shown in the flag symbols in the figure.
**MORE DATA FLAG**  **NOTE**Color photographs of typical single structural glass pane No. 2 and No. 3 window damage can be found in Fleet Team Digest Articles 747 FTD 56-05001 and 747-400 FTD 56-05001. These articles can be accessed through the MyBoeingFleet website, or you may obtain copies from your local Boeing Field Service office. 1

**FIGURE 2: 65B27042-( ) AND 65B27043-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW DETAILED INSPECTION**  **(SHEET 6 OF 6)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 45 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 1 OF 7)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 46 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 2 OF 7)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 47 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 3 OF 7)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 48 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 4 OF 7)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 49 of 52 **BOEING SERVICE BULLETIN 747-56A2012 FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW**  **DETAILED INSPECTION (SHEET 5 OF 7)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 50 of 52 **BOEING SERVICE BULLETIN 747-56A2012**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b) (c) (d) (e) 1
- Left No. 3 Window Inspect 1

**FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW DETAILED INSPECTION**  **(SHEET 6 OF 7)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 51 of 52 **BOEING SERVICE BULLETIN 747-56A2012 MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) (b) (c) (d) (e) 1
- Left No. 2 Window Inspect 2 (a) (b) (c) (d) (e) 1
- Right No. 2 Window Inspect 3 (a) (b) (c) (d) (e) 1
- Right No. 3 Window Inspect 4 (a) Do an internal detailed inspection of the flight deck window for the following cracks or damage: fail-safe interlayer cracks, glass pane cracks and chips, and indications of arcing. An optional external detailed inspection of the flight deck window for the damage may be necessary if the existing window conditions do not allow complete inspection from the inside of the flight deck. Any non-clear damage should be noted that may hinder inspection of the damage. (b) Inspect the window for fail-safe interlayer cracks along the metal edge insert. Fail-safe interlayer cracks can be at any location in the window, but are usually found along the metal edge insert. As of the issue date of this service bulletin, on 65B27046-( ) and 65B27047-( ) single structural glass pane No. 2 and No. 3 windows cracks have only been found in the inboard urethane fail-safe interlayer. No cracks have been found in the vinyl fail-safe interlayer. The inboard urethane fail-safe interlayer cracks that have been found do not run parallel to the edges of the window. Instead, they appear to be in random in directions close to the window attachment bolt holes. Inboard urethane fail-safe interlayer cracks are frequently accompanied by white or yellow discoloration of the urethane. (c) On 65B27046-( ) and 65B27047-( ) single structural glass pane No. 2 and No. 3 windows, the outboard urethane interlayer is considered to be non-structural. This layer is 0.02 inch thick and is located adjacentto the outer glass pane. White or yellow discoloration and cracking in this layer is considered to be acceptable, as long as the pilot's vision is not obscured. (d) Inspect the window for glass pane cracks and chips. There are many types of chips but pay particular attention to "V" shaped chips and peel chips. "V" shaped chips occur on the external surface of the glass pane and have a sharp narrow "V" where the depth is equal to or larger than the width. "V" shaped chips occur on the external surface of the glass pane and have a sharp narrow "V" where the depth is equal to or larger than the width. Peel chips occur on the internal surface of the glass pane and these areas have a curved, rough grained shape, and are easily seen in reflected light. The area of the peel chips can have small glass flakes, usually white, and view through the window will distort through the rough surface of the chip. Peel chips start very small but can continue to grow with the continued use of the airplane. (e) Inspect the window for any indications of arcing. An arc can occur due to an electrical discharge or short circuit across a wire, bus bar, conductive heating film or other internal window components. Arcs usually occur near the window bus bars, and are typically the result of moisture ingress. The heat from an arc can cause dark brown or black burn marks on the bus bar and in the interlayer. Arcs in the heating film away from the bus bar can occur as a jagged line. The flag note number shown below agrees with the number shown in the flag symbols in the figure.
**MORE DATA FLAG**  **NOTE**Color photographs of typical single structural glass pane No. 2 and No. 3 window damage can be found in Fleet Team Digest Articles 747 FTD 56-05001 and 747-400 FTD 56-05001. These articles can be accessed through the MyBoeingFleet website, or you may obtain copies from your local Boeing Field Service office. 1

**FIGURE 3: 65B27046-( ) AND 65B27047-( ) SINGLE STRUCTURAL GLASS PANE NO. 2 AND NO. 3 WINDOW DETAILED INSPECTION**  **(SHEET 7 OF 7)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: August 24, 2006 747-56A2012 Revision 1 August 12, 2010 52 of 52 **BOEING SERVICE BULLETIN 747-56A2012**