### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-25A3588**  Original Issue: July 19, 2010 Revision 1: April 07, 2011 ATA System: 2551 **SUBJECT:** EQUIPMENT/FURNISHINGS - Electrical/Electronic Equipment Centers - Main Equipment Center Drip Shield Repair 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 1 of 38 4.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 2 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 7 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 17 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 20 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 21 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 FIGURE 1: MEC DRIP SHIELD CLEANING AND PREPARATION . . . . . . . . . . . . . . . . . . . 25 FIGURE 2: REPAIR OF HOLES IN MEC DRIP SHIELD. . . . . . . . . . . . . . . . . . . . . . . . . 29 FIGURE 3: MEC DRIP SHIELD PANEL STIFFENER INSTALLATION [Group 1, 3]. . . . . . . . . . . 32 FIGURE 4: MEC DRIP SHIELD FIBERGLASS REINFORCING OVERCOAT INSTALLATION. . . . . 36

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 3 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 4 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Revision Transmittal Sheet**  **Number: 747-25A3588** Original Issue: July 19, 2010 Revision 1: April 07, 2011 ATA System: 2551 **SUBJECT:** EQUIPMENT/FURNISHINGS - Electrical/Electronic Equipment Centers - Main Equipment Center Drip Shield Repair This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** No more work is necessary on the airplane(s) changed in accordance with the original issue of this service bulletin. **REASON FOR REVISION** This revision is sent to remove airplane RT101 and correct the Operator Supplied materials table. These sections were changed: 1. Paragraph 1.A., Effectivity - removed airplane RT101. RT101 was modified from passenger to freighter using non-Boeing engineering 2. Paragraph 2.C.2., Parts and Materials Supplied by the Operator - Added BMS 8-2, Type 13, Any Class, Grade A. 3. Paragraph 2.C.2., Parts and Materials Supplied by the Operator - Changed the acceptable BMS 8-2 grade from Grade B to Grade A. 4. Figure 3 - Added instructions to apply a fillet of BMS 5-92 around the perimeter of the panel stiffeners. 5. Figure 4 - Changed the outboard limits of the fiberglass cloth from LBL/RBL 60 to 2.00 minimum overlap past the LBL/RBL 49 seams. 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. The data given in Information Notice 747-25A3588 R00 IN01 is included in this revision.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 5 of 38**REVISION HISTORY** July 19, 2010 Original Issue: April 07, 2011 Revision 1:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 6 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Summary**  **Number: 747-25A3588** Original Issue: July 19, 2010 Revision 1: April 07, 2011 ATA System: 2551 **SUBJECT:** EQUIPMENT/FURNISHINGS - Electrical/Electronic Equipment Centers - Main Equipment Center Drip Shield Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** This service bulletin will reduce the possibility of water penetration into the main equipment center (MEC). Cracking of the MEC drip shield has allowed water to drip past the MEC drip shield and through the exhaust plenum into the MEC. Water penetration into the MEC could result in loss of flight critical systems. An operator experienced a loss of bus control unit (BCU) #1 and generator control units (GCU's) #1 and #2 while the airplane was still on the ground. Cracking in the MEC drip shield and exhaust plenum have each been identified as part of the leak path into the MEC. Multiple operators have reported cracked MEC drip shield. These cracks can allow water to penetrate the MEC drip shield and enter the MEC. This service bulletin will install a fiberglass reinforcing overcoat as a terminating action. Boeing Service Related Problem (SRP) 747-SRP-25-0284 is related to this service bulletin. **ACTION (PRR 85901-102RS)** - Install honeycomb stiffening panels - Install a fiberglass reinforcing overcoat **EFFECTIVITY** 747-400F/-400 Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 7 of 38**COMPLIANCE** 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 that the inspection, change and/or repair given in this service bulletin be done within 24 months after the original issue date of this service bulletin. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are available for airplanes in warranty as of January 14, 2009. Please refer to Paragraph 2.B., Industry Support Information. **MANPOWER Group 1, 3:**  **Elapsed Hours Total Task Hours**  **Airplanes** 12.75 20.50 Group 1, 3 **Group 2: Elapsed Hours**  **Total Task Hours Airplanes**  9.00 16.75 Group 2
**MATERIAL INFORMATION** Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 8 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 9 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 10 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 747 Service Bulletin **ALERT Number: 747-25A3588**  Original Issue: July 19, 2010 Revision 1: April 07, 2011 ATA System: 2551 **SUBJECT:** EQUIPMENT/FURNISHINGS - Electrical/Electronic Equipment Centers - Main Equipment Center Drip Shield Repair THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes Refer to Service Bulletin Index Document D6-30300 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR 85901-102RS for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** 747-400 Freighter airplanes that have molded stiffening beads on the MEC drip shield. - 1
747-400 Freighter airplanes that have aluminum stiffeners installed on the top of the MEC drip shield by SB 747-25A3086 or in production. - 2
747-400 BCF airplanes that have molded stiffening beads on the MEC drip shield. - 3

Airplane Models: 747-400, 747-400F **Group Variable Number**  2 RL401 - RL402

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 11 of 38**Group Variable Number**  1 RL403 2 RL411 - RL418 1 RL419 - RL436 1 RL451 - RL456 1 RL461 - RL462 1 RL471 - RL481 1 RL491 - RL492 1 RL501 - RL502 1 RL511 - RL516 1 RL521 - RL522 1 RL531 - RL534 1 RL551 1 RL561 - RL568 1 RL571 - RL572 1 RL576 - RL577 1 RL579 1 RL581 - RL586 2 RL651 - RL654 1 RL655 1 RL671 - RL675 1 RL681 - RL684 1 RL751 - RL752 3 RM128 2 RM851 - RM858 1 RM859 2 RM861 1 RM862 - RM863 2 RM871 - RM876 1 RM877 - RM880 2 RM881 - RM886 1 RM887 - RM890 2 RM891 - RM899 2 RM901 - RM903

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 12 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT Group**  **Variable Number** 1 RM904 - RM906 2 RM911 2 RR701 2 RR721 - RR724 2 RR746 - RR748 2 RR851 - RR856 2 RR861 - RR862 2 RR951 - RR952 3 RT021 - RT022 3 RT031 - RT033 3 RT071 - RT072 3 RT075 3 RT161 3 RT164 3 RT456 3 RT461 3 RT501 3 RT506 - RT510 3 RT513 3 RT516 3 RT518 - RT520 3 RT524 3 RT526 3 RT528 3 RT530 3 RT572 - RT579 3 RT642 3 RT655 - RT657 3 RT751 - RT752 3 RT781 - RT782 3 RT837 3 RT967

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 13 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** This service bulletin will reduce the possibility of water penetration into the main equipment center (MEC). Cracking of the MEC drip shield has allowed water to drip past the MEC drip shield and through the exhaust plenum into the MEC. Water penetration into the MEC could result in loss of flight critical systems. An operator experienced a loss of bus control unit (BCU) #1 and generator control units (GCU's) #1 and #2 while the airplane was still on the ground. Cracking in the MEC drip shield and exhaust plenum have each been identified as part of the leak path into the MEC. Multiple operators have reported cracked MEC drip shield. These cracks can allow water to penetrate the MEC drip shield and enter the MEC. This service bulletin will install a fiberglass reinforcing overcoat as a terminating action. Boeing Service Related Problem (SRP) 747-SRP-25-0284 is related to this service bulletin. Revision 01 is sent to remove airplane RT101 and correct the Operator Supplied materials table. **D. Description** - Install honeycomb stiffening panels - Install a fiberglass reinforcing overcoat Revision 01 - No more work is necessary on airplanes changed in accordance with the original issue of this service bulletin. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1-2:**
**Affected Maintenance Zones Zone**  **Model** 117, 118 747-400F

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 14 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT Group 3:** 
**Affected Maintenance Zones Zone**  **Model** 117, 118 747-400 **E. Compliance** 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 that the inspection, change and/or repair given in this service bulletin be done within 24 months after the original issue date of 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. **G. Manpower** The table below shows an estimate of the task hours necessary to do this change 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 cure the materials • Time to make the parts • Time to find the tools. **Group 1, 3: MEC Drip Shield Reinforcing Fiberglass Overcoat**  **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**
3.00 6.00 2 Open Access 1.75 3.50 1 Figure 1

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 15 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT Group 1, 3:**  **MEC Drip Shield Reinforcing Fiberglass Overcoat Elapsed Hours**  **Task-Hours Number of Per-**  **sons Task**  0.50 (a) 0.50 (a) 1 Figure 2 3.75 3.75 1 Figure 3 1.25 1.25 1 Figure 4 3.00 6.00 2 Close Access 12.00 19.75 Total per airplane (a) Estimate is per hole to be repaired and is not included in total given. Operator should multiply number of holes to be repaired by estimate shown and add to total to arrive at revised total. **Group 2: MEC Drip Shield Reinforcing Fiberglass Overcoat**  **Elapsed Hours Task-Hours**  **Number of Per- sons**  **Task**
3.00 6.00 2 Open Access 3.50 3.50 1 Figure 1 0.50 (a) 0.50 (a) 1 Figure 2 1.25 1.25 1 Figure 4 3.00 6.00 2 Close Access 9.00 16.75 Total per airplane (a) Estimate is per hole to be repaired and is not included in total given. Operator should multiply number of holes to be repaired by estimate shown and add to total to arrive at revised total. **H. Weight and Balance Changes Group 1, 3:**  **Change in Moment (Pound-Inches)**  **Change in Weight (Pounds)**  **Airplane** +1485.0 +3.3 Group 1, 3 **Group 2: Change in Moment**  **(Pound-Inches) Change in Weight**  **(Pounds) Airplane**  +1305.0 +2.9 Group 2

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 16 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT I. Electrical Load Data**  Not changed. **J. References** 1. Existing Data a. Engineering Change Memo PRR 85901-102RS b. Boeing Service Related Problem (SRP) 747-SRP-25-0284 c. Standard Overhaul Practices Manual (SOPM) 20-30-03, 20-50-12 d. 747-400 Aircraft Maintenance Manual (AMM) 25-00-00, 25-57-01, 25-57-04, 25-57-06, 25-58-01, 25-58-02, 53-21-02 e. 747-400 Structural Repair Manual (SRM) 51-70-06 2. Data supplied with this Service Bulletin None. 3. Installation Drawings Used in the Preparation of this Service Bulletin None. **K. Publications Affected** 1. Publications: **Chapter-Section Publication**  25-51, 51-41 747 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: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 17 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 18 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the kits shown in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145 **Group 1: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER**  **AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION**
**Unit Price as of the original issue** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** **vice Bulletin (Cal endar Days)**  **QTY Date**  **Name Kit Number** 

$1,109.00 150 39 October 6, 2010 TOP KIT - MEC DRIP SHIELD REPAIR 015U1895-1
**Group 3: REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RESPONDER**  **AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE INFORMATION**
**Unit Price as of the original issue** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** **vice Bulletin (Cal endar Days)**  **QTY Date**  **Name Kit Number** 

$1,109.00 150 12 October 6, 2010 TOP KIT - MEC DRIP SHIELD REPAIR 015U1896-1
**B. Industry Support Information** Boeing warranty remedies are available for 747 airplanes in warranty as of January 14, 2009. For inspection task hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. If the condition described in this service bulletin is found during the inspection for airplanes in warranty as of that date and additional task hours and kits are required, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. Please refer to this service bulletin number and reference the airplane variable numbers in your purchase order.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 19 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT C. Parts Necessary For Each Airplane**  1. Kits/Parts To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. **Figure Kit 3**  **Top Kit** 1 015U1895-1 1 015U1896-1 **Group 1:**
**KIT 015U1895-1**

**NOTES Existing Part**  **Number Name**  **Figure**

**New Part Number 3**  **QTY** (a) HONEYCOMB CORE PANEL 1 284U1135-98 (a) HONEYCOMB CORE PANEL 2 284U1135-99 (a) This part not used in production. **Group 3:**
**KIT 015U1896-1**

**NOTES Existing Part**  **Number Name**  **Figure**

**New Part Number 3**  **QTY** (a) HONEYCOMB CORE PANEL 1 284U1135-98 (a) HONEYCOMB CORE PANEL 2 284U1135-99 (a) This part not used in production. 2. Parts and Materials Supplied by the Operator
**Notes Name**  **QTY Part Number /**  **Specification** (a) ADHESIVE 1 Qt BMS 5-92, Any Type

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 20 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT Notes**  **Name QTY**  **Part Number / Specification**  (a) SEALANT

- BMS 5-95, Type I, Class B (a) FIBERGLASS SHEET

- BMS 8-2, Type 13, 23, 26, or 35, Any Class, Grade A (a) EPOXY RESIN 1 Qt BMS 8-201, Type III or Type IV (a) FIBERGLASS CLOTH 1 Roll BMS 9-3, TYPE H, H-2, or H-3, CLASS 7 (b) PHENOLIC MICROBALLOONS 1 oz Phenoset Micro-spheres, No. BJ0930 (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Malayan Adhesives & Chemicals Sdn Bhd, No 9, Jalan Utas 15/7, P. O. BOX 7086, 40702 Shah Alam, Selangor Darul Ehsan, Malaysia. (603) 5566-1188
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: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 21 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 22 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**

BLANK PAGE**3. ACCOMPLISHMENT INSTRUCTIONS A. GENERAL INFORMATION**  **CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. The instructions identified in Paragraph 3.B., Work Instructions, and the Figure(s) give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 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 5. 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. 6. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. **B. WORK INSTRUCTIONS** 1. Remove cargo handling equipment between STA 420 and STA 460 and LBL 55 and RBL 55. Refer to 747-400 AMM 25-57-01, 747-400 AMM 25-57-04, 747-400 AMM 25-57-06, 747-400 AMM 25-58-01, 747-400 AMM 25-58-02 as an accepted procedure. 2. Remove main deck floor panels between STA 420 and STA 460 and LBL 55 and RBL 55. Refer to 747-400 AMM 53-21-02 as an accepted procedure. 3. Clean the MEC drip shield and do a general visual inspection for cracks and holes on the top surface of the MEC drip shield in accordance with Figure 1.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 23 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**a. If any crack is found, repair the crack. Refer to 747-400 AMM 25-00-00 as an accepted procedure. b. If any hole is found, repair the hole in accordance with Figure 2.

c. **Group 1, 3:** If no cracks or holes are found, proceed to Work Instruction 4. d. **Group 2:** If no cracks or holes are found, proceed to Work Instruction 5. 4. **Group 1, 3:** Install MEC drip shield panel stiffeners in accordance with Figure 3 5. Install fiberglass reinforcing overcoat to MEC drip shield in accordance with Figure 4. 6. Install main deck floor panels between STA 420 and STA 460 and LBL 55 and RBL 55. Refer to 747-400 AMM 53-21-02 as an accepted procedure. 7. Install cargo handling equipment between STA 420 and STA 460 and LBL 55 and RBL 55. Refer to 747-400 AMM 25-57-01, 747-400 AMM 25-57-04, 747-400 AMM 25-57-06, 747-400 AMM 25-58-01, 747-400 AMM 25-58-02 as an accepted procedure. 8. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1: April 07, 2011 24 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT FIGURE 1: MEC DRIP SHIELD CLEANING AND PREPARATION**  **(SHEET 1 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 25 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT FIGURE 1: MEC DRIP SHIELD CLEANING AND PREPARATION**  **(SHEET 2 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 26 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.

**FIGURE 1: MEC DRIP SHIELD CLEANING AND PREPARATION (SHEET 3 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 27 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** Solvent clean, refer to SOPM 20-30-03as an accepted procedure. - - MEC DRIP SHIELD Clean 1

Carefully remove any loose old sealant along BL49 and BL 0 seams andaround any fasteners without causing further damage to MEC drip shield. - - SEALANT Remove 2

Solvent clean, refer to SOPM 20-30-03as an accepted procedure. - - MEC DRIP SHIELD Clean 3

Abrasive clean, refer to SOPM 20-30-03as an accepted procedure. - - MEC DRIP SHIELD Clean 4

Solvent clean, refer to SOPM 20-30-03as an accepted procedure. - - MEC DRIP SHIELD Clean 5

Apply sealant to area where oldsealant was removed along BL49 and BL 0 seams andaround any fasteners. Refer to SOPM20-50-12 as an accepted procedure. - BMS 5-95 SEALANT Apply 6

Do a general visual inspection of theMEC drip shield surface for cracks or broken areas. - - MEC DRIP SHIELD Inspect 7

**FIGURE 1: MEC DRIP SHIELD CLEANING AND PREPARATION (SHEET 4 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 28 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT FIGURE 2: REPAIR OF HOLES IN MEC DRIP SHIELD**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 29 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.

**FIGURE 2: REPAIR OF HOLES IN MEC DRIP SHIELD (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 30 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** Cut MEC drip shield to remove material around broken area. - - MEC DRIP SHIELD Cut 1

Cut a piece of BMS 8-2 FIBERGLASS SHEET to cover the removed section with a minimum 2.0 inch overlap. 1 BMS 8-2 FIBERGLASS SHEET Cut 2

Bond using BMS 5- 92. Refer to 747-400 SRM 51-70-06 as an accepted procedure. 1 BMS 8-2 FIBERGLASS SHEET Bond 3

**FIGURE 2: REPAIR OF HOLES IN MEC DRIP SHIELD (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 31 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT This Figure applies only to: Group 1, 3.** 

**FIGURE 3: MEC DRIP SHIELD PANEL STIFFENER INSTALLATION (SHEET 1 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 32 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.

**FIGURE 3: MEC DRIP SHIELD PANEL STIFFENER INSTALLATION (SHEET 2 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 33 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** Install fiberglass strips along seams at BL 0, LBL 49, and RBL 49. Fiberglass cloth should extend 3 inches on either side of the seams. Bond using BMS 8- 201 Type III or Type IV. Refer to 747-400 SRM 51-70-06 as an accepted procedure. - BMS 9-3, TYPE H, H-2, OR H-3, CLASS 7 FIBERGLASS CLOTH Install (New) 1

Locate honeycomb core panel between molded stiffening beads as shown. 1 284U1135-98 HONEYCOMB CORE PANEL Locate 2

Locate honeycomb core panel between molded stiffening beads as shown. 2 284U1135-99 HONEYCOMB CORE PANEL Locate 3

Drill .094 inch holes, as required, thru honeycomb core panel and MEC drip shield to install enough clecos to pull the top surface of the MEC drip shield flat. - - HOLE Drill 4

Install enough clecos to pull the top surface flat against the honeycomb core panel. - - CLECO Install (New)

- - CLECO Remove

**FIGURE 3: MEC DRIP SHIELD PANEL STIFFENER INSTALLATION (SHEET 3 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 34 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** Bond using BMS 5- 92. Refer to 747-400 SRM 51-70-06 as an accepted procedure. - BMS 5-92 ADHESIVE Apply 5

Bond using BMS 5- 92. Refer to 747-400 SRM 51-70-06 as an accepted procedure. 1 284U1135-98 HONEYCOMB CORE PANEL Install (New)

- - CLECO Install (New) Optional, a fillet may be added around thepanel stiffener to reduce air bubbles when fiberglass cloth is overlaid. (a) - BMS 5-92 ADHESIVE Apply

Bond using BMS 5- 92. Refer to 747-400 SRM 51-70-06 as an accepted procedure. - BMS 5-92 ADHESIVE Apply 6

Bond using BMS 5- 92. Refer to 747-400 SRM 51-70-06 as an accepted procedure. 2 284U1135-99 HONEYCOMB CORE PANEL Install (New)

- - CLECO Install (New) Optional, a fillet may be added around thepanel stiffener to reduce air bubbles when fiberglass cloth is overlaid. (a) - BMS 5-92 ADHESIVE Apply

Remove clecos after panel has cured to the top surface of the MEC drip shield. - - CLECO Remove 7

(a) As an option, phenolic microballoons may be added to BMS 5-92 to increase the viscosity of the adhesive while building the fillet. Dry the microballoons at 125 to 350 F for 30 minutes +10/-0 minutes, until there is no more than 0.2 percent weight loss on successive weighing. Blend the A and B components of BMS 5-92 in accordance with SOPM 20-50-12, Type 70, and then add fifteen parts by weight of microballoons to one hundred parts by weight of blended BMS 5-92 and blend thoroughly.

**FIGURE 3: MEC DRIP SHIELD PANEL STIFFENER INSTALLATION (SHEET 4 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 35 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT FIGURE 4: MEC DRIP SHIELD FIBERGLASS REINFORCING OVERCOAT INSTALLATION**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 36 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a)

- BMS 9-3, TYPE H, H-2, OR H-3, CLASS 7 FIBERGLASS CLOTH Cut 1 (b)

- BMS 8-201 EPOXY RESIN Prepare 2

- BMS 9-3, TYPE H, H-2, OR H-3, CLASS 7 FIBERGLASS CLOTH Install (New) 3 Bond using BMS 8- 201 Type III or Type IV. Refer to 747-400 SRM 51-70-06 as an accepted procedure. - BMS 8-201 EPOXY RESIN Apply

**FIGURE 4: MEC DRIP SHIELD FIBERGLASS REINFORCING OVERCOAT INSTALLATION (SHEET 2 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 37 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (a) Cut fiberglass cloth to overlay the MEC drip shield, in sections as required. Two plies will be required. Cloth shall extend over sides to within 0.25 inch of bottom of the MEC drip shield. Cloth shall extend a minimum of 2" outboard of the LBL/RBL 49 seams. All seams shall overlap 2 inch minimum, including sheet-to-sheet and sheet-to-beam. (b) Prepare epoxy laminating resin in sufficient quantity. Work in small batches consistent with working life of resin. Apply mixed resin and cloth using squeegee or similar tool.

**FIGURE 4: MEC DRIP SHIELD FIBERGLASS REINFORCING OVERCOAT INSTALLATION (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 19, 2010 747-25A3588 Revision 1 April 07, 2011 38 of 38 **BOEING SERVICE BULLETIN 747-25A3588 ALERT**  **ALERT**