### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-27A1278**  Original Issue: May 24, 2007 Revision 1: January 07, 2010 ATA System: 2741 **SUBJECT:** FLIGHT CONTROLS - Horizontal Stabilizer Trim Control System - Ballscrew and Ball Nut Inspection and Lubrication 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## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2007 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 1 of 83 5.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 2 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Revision Transmittal Sheet............................................ 5 Summary...................................................... 9 1. PLANNING INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 A. Effectivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 1. Airplanes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 G. Manpower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 1. Existing Data:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 40 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 1. Kits/Parts:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 43 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 44 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 FIGURE 1: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND THE ATTACHMENT FITTINGS- (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES) [Group 1-2, Configuration 1; Group 3]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 FIGURE 2: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND THE ATTACHMENT FITTINGS - (GROUP 1, CONFIGURATION 2 AIRPLANES) [Group 1, Configuration 2]. . . . . . . . . . . . . . . . . . . . . . . . . . 63 FIGURE 3: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND, AND THE ATTACHMENT FITTINGS - (GROUP 2, CONFIGURATION 2 AIRPLANES) [Group 2, Configuration 2]. . . . . . . . . . . . . . . 67

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 3 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**FIGURE 4: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES) [Group 1-2, Configuration 1; Group 3]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 FIGURE 5: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 1, CONFIGURATION 2 AIRPLANES) [Group 1, Configuration 2]. . . . . . . . . . . . . . . 73 FIGURE 6: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 2, CONFIGURATION 2 AIRPLANES) [Group 2, Configuration 2]. . . . . . . . . . . . . . . 75 FIGURE 7: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES) [Group 1-2, Configuration 1; Group 3]. . . . . . . . . . . . . . . 77 FIGURE 8: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 1, CONFIGURATION 2 AIRPLANES) [Group 1, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 FIGURE 9: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 2, CONFIGURATION 2 AIRPLANES) [Group 2, Configuration 2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Appendix A: INSPECTION REPORT FORM FOR SB 737-27A1278. . . . . . . . . . . . . . . . . . . 83

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 4 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**

### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Revision Transmittal Sheet**  **Number: 737-27A1278** Original Issue: May 24, 2007 Revision 1: January 07, 2010 ATA System: 2741 **SUBJECT:** FLIGHT CONTROLS - Horizontal Stabilizer Trim Control System - Ballscrew and Ball Nut Inspection and Lubrication This revision includes all pages of the service bulletin. **COMPLIANCE INFORMATION RELATED TO THIS REVISION** No more work is necessary on airplanes changed as shown in the original issue of this service bulletin. However, Operators have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul in accordance with Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable. Federal Aviation Administration (FAA) Notice of Proposed Rule Making FAA NPRM 2007-NM-256-AD, is related to this service bulletin. **NOTE:**The Operators that performed the initial Detailed Inspection, Lubrification, and Overhaul do not have to do another initial inspection, but have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator in accordance with Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable. The Operators that incorporated service bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 or service bulletin LINEAR MOTION, LLC SB 7901708 or service bulletin SKYTRONICS, Inc. SB 93004 as given in WORK PACKAGE 4, have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator in accordance with Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable. The Operators that did not incorporate UMBRA CUSCINETTI S.p.A. or LINEAR MOTION LLC or SKYTRONIC INC service bulletin, have to incorporate service bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 or service bulletin LINEAR MOTION, LLC SB 7901708 or service bulletin SKYTRONICS, Inc. SB 93004 as given in WORK PACKAGE 4, and have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator in accordance with Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 5 of 83**REASON FOR REVISION** This revision is sent to correct the work instructions for the HSTA name plate identification information in WORK PACKAGE 4 and to clarify some of the inspections necessary in WORK PACKAGE 1 and WORK PACKAGE 2. A note is also added in the compliance table to advise operators to do the lubrication task during the detailed inspection task. In addition, reference to the "Horizontal Stabilizer Gearbox End Play Test as given OHM 27-45-11" is added. This is because the Horizontal Stabilizer Gearbox Backlash Inspection is only given in the AMM for 737-600/700/800/900 airplane. The (OHM) Horizontal Stabilizer Gearbox End Play Test is a similar test and is applicable to all 737-100/200/300/400/500 airplane variants. These sections are changed: 1. Paragraph 1.D., Description: Affected Maintenance Zones are added for each airplane group. 2. Paragraph 1.E., Compliance: Notes (a) and (b) are added to Table 1 and Table 2 to recommend operators to do a lubrication task during the detailed inspection task. 3. Paragraph 1.E., Compliance: Notice of Propose Rule Making 2007-NM-256-AD is added. 4. Paragraph 1.K., Publications Affected: Added Damage Tolerance Based Structural Inspection statement. 5. Paragraph 3.A, General Information: General Visual Inspection note added. 6. Paragraph 3.B, Work Instructions: a. WORK PACKAGE 1: – Added some notes, added more data to some step instructions, deleted some unnecessary step instructions and correctly re-sequenced the steps. b. WORK PACKAGE 2: – Added some notes, added more data to some step instructions, deleted some unnecessary step instructions and correctly re-sequenced the steps. c. WORK PACKAGE 4: – Step 1.a. revised to reference SB 737-27A1278 WORK PACKAGE 4 instead of 737-27A1278 WORK PACKAGE 3. – Step 2.a. revised to reference SB 737-27A1278 WORK PACKAGE 4 instead of 737-27A1278 WORK PACKAGE 3. – Step 3.b. revised to reference SB 737-27A1278 WORK PACKAGE 4 instead of 737-27A1278 WORK PACKAGE 3. 7. FIGURE 1: Step 10, inspection for large amount of grease that exits the Ball Nut and note (a) are removed. 8. FIGURE 2: Step 10, inspection for large amount of grease that exits the Ball Nut and note (a) are removed.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 6 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**9. FIGURE 7 sheet 2: Step 4, reference to Aircraft Maintenance Manual (AMM) removed and replaced with internal reference note (b). Also the step table note (b) is revised to reference Horizontal Stabilizer Gearbox End Play Test as given in OHM 27-45-11 instead of the Horizontal Stabilizer Gearbox Backlash inspection as given in AMM 27-41-81/606. 10. FIGURE 8 sheet 2: Step 4, reference to Aircraft Maintenance Manual (AMM) removed and replaced with internal reference note (b). Also the step table note (b) is revised to reference Horizontal Stabilizer Gearbox End Play Test as given in OHM 27-45-11 instead of the Horizontal Stabilizer Gearbox Backlash inspection as given in AMM 27-41-81/606. 11. FIGURE 9 sheet 2: Step 4, reference to Aircraft Maintenance Manual (AMM) removed and replaced with internal reference note (b). Also the step table note (b) is revised to reference Horizontal Stabilizer Gearbox End Play Test as given in OHM 27-45-11 instead of the Horizontal Stabilizer Gearbox Backlash inspection as given in AMM 27-41-81/606. The data given in Information Notice 737-27A1278 IN 01 is included in this revision. Vertical lines are put on the left edge of each page, except in Paragraph 1.A., Effectivity, to show the location of important changes. Pages with no vertical lines have no important changes. **REVISION HISTORY** May 24, 2007 Original Issue: January 07, 2010 Revision 1:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 7 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 8 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Summary**  **Number: 737-27A1278** Original Issue: May 24, 2007 Revision 1: January 07, 2010 ATA System: 2741 **SUBJECT:** FLIGHT CONTROLS - Horizontal Stabilizer Trim Control System - Ballscrew and Ball Nut Inspection and Lubrication 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 is being issued to maintain the frequency of the detailed inspection of the Horizontal Stabilizer Trim Actuator (HSTA) Ballscrew and Ball Nut as specified in the Maintenance Planning Document. This service bulletin also gives instructions to remove/replace and repair the Horizontal Stabilizer Trim Actuator if a damaged Ballscrew or Ball Nut is found. This service bulletin also adds the recommended intervals for repeat lubrication and overhaul. Also, this service bulletin gives recommended compliance time for incorporation of the suppliers service bulletins (service bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01, service bulletin LINEAR MOTION, LLC SB 7901708, and service bulletin SKYTRONICS, Inc. SB 93004). The UMBRA CUSCINETTI supplier service bulletin provides instructions to remove and replace the Ball Nut Tube Retainers on the 737 Horizontal Stabilizer Trim Actuator Ballscrew assembly with new Tube Retainers. The LINEAR MOTION supplier service bulletin provides instructions to remove and replace the Ball Deflectors and the Ball Return Guide Clamps on 737 Horizontal Stabilizer Trim Actuator Ballscrew assembly with new Ball Deflectors and Ball Return Guide Clamps. The SKYTRONICS supplier service bulletin provides instructions to remove and replace the Return Tube Clamps on the 737 Horizontal Stabilizer Trim Actuator Ballscrew assembly with new Return Tube Clamps. The new parts installed will have sufficient stiffness to retain the load carrying balls in all known failure mode conditions. The changes given in this bulletin will reduce the probability of loss of the primary and secondary load paths of the Stabilizer Trim Actuator. Loss of primary and secondary load paths of the Stabilizer Trim Actuator could result in the loss of control of the airplane. This Service Bulletin also specifies the time for incorporation of the Boeing Service Bulletin 737-27-1046 Revision 1 (as applicable), dated April 5, 1974, if the service bulletin is not already incorporated. Boeing Service Bulletin 737-27-1046 Revision 1 applies to airplanes 737-100/200 with oil lubricators and provides instructions for removing the existing oil lubricators and installation of a grease fitting on the Horizontal Stabilizer Trim Actuator Ball Nut.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 9 of 83**NOTE:**The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting as given in Boeing Service Bulletin 737-27-1046 Revision 1. Remove these Stabilizer Trim Actuator Ballscrew Assemblies with Oil Lubricator and install 102J033-3 or 102J033-502 Horizontal Stabilizer Trim Actuator Ballscrew Assembly This service bulletin is being issued to maintain the frequency of the detailed visual inspection of the Horizontal Stabilizer Trim Actuator Ballscrew and Ball Nut as specified in the Maintenance Planning Document. This service bulletin also gives instructions to remove/replace and repair the Horizontal Stabilizer Trim Actuator if a damaged Ballscrew or Ball Nut is found. This service bulletin also adds the recommended intervals for repeat lubrication and overhaul. After a Horizontal Stabilizer jackscrew incident related to a MD-80 airplane, Boeing initiated a design review of the Boeing heritage horizontal stabilizer ballscrew primary and secondary load paths. During this review, one 757 operator reported a Horizontal Stabilizer Ballscrew with extensive corrosion. An investigation was initiated. This investigation identified that a maintenance procedure to check the stabilizer Ballscrew primary load path was required. In addition, the design review found that the Ball Nut Tube Retainers on the 737 Horizontal Stabilizer Trim Actuator should be stiffened, so that the balls are retained within the assembly when the balls are jammed and not free to circulate. **NOTE:**Boeing also recommends that the Maintenance Planning Document (MPD) intervals be observed for the "Lubrication" and "Detailed Inspection" actions prior to compliance with this service bulletin. The "Lubrication" and "Detailed Inspection" done as given in this service bulletin satisfy the "Lubrication" and "Detailed Inspection" requirements given in Maintenance Planning Document" (MPD). Boeing Service Related Problem (SRP) 737CL-SRP-27-0153 is related to this bulletin. **ACTION (PRR 35005-261RS)** Get access to the Horizontal Stabilizer Trim Actuator and do the procedures that follow below at the intervals shown in the compliance section. 1. DETAILED INSPECTION: – Do the Detailed Inspection as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 1 or WORK PACKAGE 2 (as applicable). LUBRICATE THE HORIZONTAL TRIM ACTUATOR: – Do the lubrication as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 1 or WORK PACKAGE 2 (as applicable). REMOVE and REPAIR/REPLACE THE HORIZONTAL TRIM ACTUATOR: Remove/Replace the Horizontal Stabilizer Trim Actuator if damage is found as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 1 or WORK PACKAGE 2 (as applicable). **NOTE:**As an option, Operators can replace a damaged Horizontal Stabilizer Trim Actuator with a serviceable Stabilizer Trim Actuator that is not new or not overhauled. Before the next flight, do the Detailed Inspection and Lubrication for the replacement Stabilizer Trim Actuator as given in this service bulletin and do the End Play Test as given in OHM 27-45-11. After the installation follow the requirements of this service bulletin. 2. For airplanes with Horizontal Stabilizer Trim Actuator Ballscrew Assemblies with Oil Lubricators:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 10 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**a. CHECK the Horizontal Stabilizer Trim Actuator Ballscrew Assy Part Number. If you find Horizontal Stabilizer Trim Actuator Ballscrew Assemblies 102J033-1 (Boeing Part Number 10-61302-1) or 102J033-1 (OS) (Boeing Part Number 10-61302-1), remove and install Stabilizer Ballscrew Assy 102J033-3 (Boeing Part Number 10-61302-2) or 102J033-502 (Boeing Part Number 10-61302-7) as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 3. **NOTE:**The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting as given in Service Bulletin 737-27-1046 Revision 1. The 102J033-3 (Boeing Part Number 10-61302-2) is an oil lubricated Horizontal Stabilizer Trim Actuator Ballscrew Assembly and operators have to incorporate Boeing Service Bulletin 737-27-1046 Revision 1 and the SKYTRONICS, Inc. SB 93004. The 102J033-502 (Boeing Part Number 10-61302-7) is a grease lubricated Horizontal Stabilizer Trim Actuator Ballscrew Assembly with reinforced Return Tube Clamps, and Operators do not have to incorporate Boeing Service Bulletin 737-27-1046 Revision 1 and service bulletin SKYTRONICS, Inc. SB 93004. b. INCORPORATE BOEING SERVICE BULLETIN 737-27-1046 Revision 1 as applicable: Incorporate SB 737-27-1046 Revision 1 as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 3. **NOTE:**Service Bulletin 737-27-1046 Revision 1 is applicable for some 737-100/200 airplanes with Ballscrew Oil Lubricators. This Service Bulletin provides instructions for the removal of the existing Oil Lubricators and the installation of a grease fitting on the Horizontal Stabilizer Trim Actuator Ball Nut. The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting. 3. INCORPORATE ONE OF THE FOLLOWING SUPPLIER SERVICE BULLETINS as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 4: – UMBRA CUSCINETTI, S.p.A. SB 07322-27-01, Rev 00, Dated December 21, 2004: Install the new Ball Nut Tube Retainers as given in this supplier service bulletin. – LINEAR MOTION, LLC SB 7901708, Dated July 26, 2005: Install the new Ball Deflectors and Ball Return Guide Clamps as given in this supplier service bulletin. – SKYTRONICS, Inc. SB 93004, Dated September 01, 2005: Install the new Return Tube Clamps as given in this supplier service bulletin. 4. REMOVE AND REPAIR/OVERHAUL THE HORIZONTAL STABILIZER TRIM ACTUATOR: – Remove and repair/overhaul the Horizontal Stabilizer Trim Actuator as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 5. **EFFECTIVITY** All 737-100/200/300/400/500 Airplanes divided in three groups. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes. **COMPLIANCE** Refer to Paragraph 1.E., Compliance.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 11 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT INDUSTRY SUPPORT INFORMATION**  Boeing warranty remedies are available for airplanes in warranty as of June 14, 2001. Please refer to Paragraph 2.B., Industry Support Information. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** None. Refer to Paragraph 2.A., Material - Price and Availability.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 12 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 13 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 14 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-27A1278**  Original Issue: May 24, 2007 Revision 1: January 07, 2010 ATA System: 2741 **SUBJECT:** FLIGHT CONTROLS - Horizontal Stabilizer Trim Control System - Ballscrew and Ball Nut Inspection and Lubrication 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 D6-19567 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below. Refer to PRR 35005-261RS for data about this change.
**DESCRIPTION CONFIGURATION**  **GROUP** 737-300/400/500 Airplanes

- 1 Airplanes with a separate Autopilot Actuator. 1 Airplanes with Primary Stabilizer Trim Actuator. 2 737-100/200 Airplanes delivered with Horizontal Stabilizer Trim Actuator Oil Lubricator. - 2
737-100/200 Airplanes that incorporated Service Bulletin 737-27-1046. 1 737-100/200 Airplanes that did not incorporate Service Bulletin 737-27-1046. 2

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 15 of 83**DESCRIPTION CONFIGURATION**  **GROUP** 737-100/200 Airplanes delivered with grease fittings on the Stabilizer Trim Actuator Ball Nut. - 3

Airplane Models: 737-100, 737-200, 737-200C, 737-300, 737-400, 737-500 **Group Variable Number**  2 PA001 - PA022 2 PA099 2 PA231 - PA232 2 PC001 - PC005 2 PG001 - PG004 3 PG005 2 PG006 - PG075 2 PG199 2 PG201 - PG230 2 PG251 - PG255 2 PG271 - PG279 2 PG301 - PG314 2 PG331 - PG332 2 PG351 - PG356 2 PG375 2 PG401 - PG403 2 PG431 - PG442 2 PG471 - PG475 2 PG501 - PG505 2 PG571 - PG586 2 PG621 - PG630 2 PG651 - PG652 2 PG701 - PG705 2 PH001 2 PH011 - PH013 3 PH021 - PH024

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 16 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 2 PH701 - PH714 3 PH715 2 PH731 - PH732 2 PH741 - PH743 2 PJ001 - PJ003 3 PJ004 - PJ009 2 PJ031 - PJ032 2 PJ071 - PJ072 2 PJ101 - PJ109 3 PJ110 - PJ119 2 PJ201 - PJ216 3 PJ217 - PJ219 1 PJ301 - PJ302 1 PJ551 - PJ561 1 PJ601 - PJ615 1 PJ811 1 PJ816 - PJ817 2 PK026 - PK027 3 PK028 - PK029 2 PK041 - PK044 3 PK045 - PK053 3 PK061 - PK070 3 PK081 - PK082 3 PK091 - PK099 3 PK101 - PK103 3 PK111 - PK120 3 PK141 - PK146 3 PK201 - PK204 3 PK211 - PK223 3 PK231 - PK241 3 PK251 - PK258 3 PK271 - PK274 3 PK281 - PK289

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 17 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 3 PK291 3 PK301 - PK318 3 PK341 3 PK351 - PK361 3 PK391 3 PK431 - PK433 3 PK451 - PK452 3 PK461 - PK469 3 PK495 3 PK501 - PK504 3 PK511 - PK515 3 PK519 3 PK521 - PK528 3 PK541 - PK565 3 PK581 3 PK591 - PK599 3 PK601 - PK617 3 PK621 - PK637 3 PK641 - PK642 3 PK661 - PK666 3 PK671 - PK681 3 PK691 - PK697 3 PK711 - PK716 3 PK731 - PK765 3 PK771 - PK779 3 PK801 - PK804 3 PK819 - PK827 3 PK830 3 PK861 - PK863 3 PK871 - PK874 3 PK881 - PK884 3 PK901 - PK938 3 PK971 - PK974

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 18 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 3 PL001 - PL028 3 PL061 3 PL081 3 PL101 - PL113 3 PL151 3 PL171 - PL172 3 PL201 - PL203 3 PL221 3 PL401 - PL417 3 PL421 3 PL441 3 PL451 - PL456 3 PL471 3 PL491 3 PL501 - PL506 3 PL551 - PL562 3 PL581 3 PL601 - PL603 3 PL611 3 PL621 - PL626 3 PL631 - PL632 2 PL711 - PL712 2 PL716 - PL717 3 PL718 - PL725 2 PL726 - PL729 3 PL730 - PL735 2 PL736 - PL742 3 PL743 - PL747 2 PL756 3 PL758 2 PL761 - PL763 3 PL764 - PL770 2 PL781 - PL782

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 19 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 3 PL783 - PL788 2 PL793 2 PL801 - PL803 3 PM001 - PM006 3 PM016 - PM017 3 PM021 - PM023 3 PM051 - PM065 1 PM066 3 PM101 - PM119 3 PM141 - PM142 3 PM171 3 PM181 3 PM251 - PM255 1 PM281 3 PM282 - PM283 1 PM381 - PM399 1 PM401 - PM417 1 PM541 - PM564 3 PN001 - PN002 3 PN021 - PN043 3 PN081 - PN086 3 PN101 - PN117 3 PN131 - PN163 3 PN401 - PN420 3 PN431 - PN433 3 PN451 - PN456 3 PN471 - PN474 3 PN481 3 PN491 - PN493 3 PN501 - PN502 3 PN511 - PN512 3 PN521 1 PP001 - PP054

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 20 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 1 PP101 - PP169 1 PP181 - PP199 1 PP201 - PP205 1 PP221 1 PP231 - PP243 1 PP281 - PP286 1 PP301 - PP305 1 PP351 - PP353 1 PP376 - PP384 1 PP391 - PP393 1 PP401 - PP440 1 PP471 - PP475 1 PP501 - PP522 1 PP631 - PP634 1 PP651 - PP652 1 PP671 - PP699 1 PP701 - PP733 1 PP771 - PP779 1 PP801 - PP808 1 PP821 - PP827 1 PP831 - PP848 1 PP851 - PP852 1 PP861 - PP877 1 PP891 - PP899 1 PP901 - PP936 1 PP946 - PP948 1 PP951 - PP952 1 PP961 - PP967 1 PP981 - PP991 1 PP993 1 PQ001 - PQ016 1 PQ026 - PQ041 1 PQ051 - PQ092

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 21 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 1 PQ101 - PQ199 1 PQ201 - PQ202 1 PQ221 - PQ237 1 PQ241 - PQ243 1 PQ251 - PQ267 1 PQ281 - PQ299 1 PQ301 - PQ307 1 PQ331 - PQ332 1 PQ341 - PQ348 1 PQ361 - PQ373 1 PQ391 - PQ395 1 PQ401 - PQ418 1 PQ421 1 PQ431 - PQ438 1 PQ447 - PQ448 1 PQ451 1 PQ454 1 PQ471 - PQ475 1 PQ479 - PQ481 1 PQ486 - PQ487 1 PQ491 - PQ493 1 PQ771 - PQ772 1 PQ791 - PQ793 1 PQ801 - PQ805 1 PQ931 - PQ935 1 PQ951 1 PQ971 - PQ997 1 PR001 - PR017 1 PR021 - PR034 1 PR041 - PR045 1 PR061 - PR072 1 PR077 - PR082 1 PR091 - PR092

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 22 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 1 PR096 1 PR101 1 PR121 - PR122 1 PR131 - PR132 1 PR141 - PR143 1 PR161 - PR172 1 PR181 1 PS601 - PS631 1 PS636 - PS638 1 PS641 - PS644 1 PS651 - PS657 1 PS666 - PS669 1 PS691 - PS692 1 PS701 - PS706 1 PS751 - PS799 1 PS811 1 PS836 - PS837 1 PS841 - PS846 1 PS851 - PS852 1 PS856 1 PS861 - PS863 1 PS866 - PS868 1 PS871 - PS874 1 PS896 - PS897 1 PS901 - PS941 1 PS956 - PS957 1 PS961 - PS963 1 PS971 - PS978 1 PT001 - PT015 1 PT021 - PT031 1 PT041 - PT064 1 PT101 - PT105 1 PT121 - PT138

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 23 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 1 PT146 - PT148 1 PT161 - PT170 1 PT181 - PT188 1 PT211 - PT220 1 PT295 1 PT301 - PT309 1 PT331 - PT360 1 PT381 - PT399 1 PT401 - PT438 1 PT501 - PT517 1 PT561 - PT565 1 PT581 - PT586 1 PT611 - PT621 1 PT641 - PT644 1 PT651 - PT656 1 PT671 - PT672 1 PT681 - PT685 1 PT701 - PT703 1 PT716 - PT717 1 PT721 - PT725 1 PT801 - PT834 1 PT851 - PT854 1 PT871 - PT886 1 PT901 - PT930 1 PT971 - PT973 1 PT981 - PT985 1 PT996 1 PU001 - PU025 1 PU301 1 PU311 - PU313 1 PV001 - PV055 1 PV201 - PV209 1 PV226 - PV229

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 24 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 1 PV231 - PV237 1 PV271 - PV272 1 PV281 - PV287 1 PV296 1 PV301 - PV302 1 PV351 1 PV356 - PV357 1 PW001 - PW054 1 PW061 - PW068 1 PW072 1 PW086 - PW088 1 PW091 - PW094 1 PW101 - PW102 1 PW106 1 PW111 - PW120 1 PW156 - PW157 1 PW161 - PW171 1 PW201 - PW252 1 PW261 - PW268 1 PW271 - PW276 1 PW278 1 PW281 - PW293 1 PW296 1 PW301 - PW327 1 PW401 - PW408 1 PW411 - PW418 1 PW421 - PW424 1 PW431 - PW435 1 PW441 - PW450 1 PW461 - PW467 1 PW501 - PW504 1 PW511 - PW522 1 PW524 - PW550

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 25 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 1 PW556 - PW557 1 PW561 - PW564 1 PW571 - PW576 1 PW591 - PW596 1 PW611 - PW622 1 PW631 - PW637 1 PW661 - PW662 1 PW681 - PW683 1 PW701 - PW702 1 PW711 - PW717 1 PW741 - PW742 1 PW761 1 PW771 1 PW831 1 PW851 - PW856 2 PX071 2 PX701 2 PY001 - PY008 2 PY021 - PY022 2 PY031 2 PY036 - PY037 2 PY046 - PY047 3 PY048 2 PY051 - PY052 3 PY053 3 PY056 - PY057 2 PY101 3 PY102 - PY103 2 PY111 - PY113 2 PY131 3 PY132 - PY135 3 PY141 - PY143 3 PY151 - PY154

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 26 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group**  **Variable Number** 3 PY156 - PY157 3 PY161 - PY162 3 PY166 3 PY191 3 PY201 3 PY221 - PY222 3 PY231 3 PY241 - PY244 3 PY270 - PY275 3 PY281 3 PY286 2 PY301 - PY304 2 PY321 - PY323 2 PY341 - PY346 2 PY361 - PY362 2 PY381 3 PY401 3 PY409 - PY411 3 PY421 - PY422 3 PY441 3 PY451 3 PY461 - PY463 3 PY591 - PY595 3 PY611 - PY612 3 PY621 3 PY631 3 PY651 3 PY671 - PY672 3 PY721 3 PY741

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 27 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**2. Spares Affected Examine your spares supply for Stabilizer Ballscrew Assembly part numbers given in the tables below and incorporate the applicable supplier service bulletin to make sure that you do not install Ballscrew Assemblies that are not reworked on airplanes that incorporated the applicable supplier service bulletin: **Boeing Part Num ber**  **Umbra Cuscinetti, S.p.A., Part Number**  **Name**

10-62210-2 07322P000-01 (a) Stabilizer Ballscrew Assy 10-62210-3 07322P000-02 (a) Stabilizer Ballscrew Assy (a) Incorporate Service Bulletin UMBRA CUSCINETTI, S.p.A.SB 07322-27-01 on these Ballscrew assemblies prior to installing the Horizontal Stabilizer Trim Actuator with the spareBallscrew Assembly on the airplane, if the Horizontal Stabilizer Trim Actuator removed had a Ballscrew Assembly withthe UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 incorporated. **Boeing Part Num ber**  **Linear Motion, LLC Part Number**  **Name**

10-61302-3 54032-003 (a) Stabilizer Ballscrew Assy 10-61302-4 54032-004 (a) Stabilizer Ballscrew Assy 10-61302-3 54032-005 (a) Stabilizer Ballscrew Assy 10-61302-3 54032-006 (a) Stabilizer Ballscrew Assy 10-61302-5 7826837 (a) Stabilizer Ballscrew Assy (a) Incorporate Service Bulletin LINEAR MOTION, LLC SB 7901708 on these Ballscrew assemblies prior to installing the Horizontal Stabilizer Trim Actuator with the spareBallscrew Assembly on the airplane, if the Horizontal Stabilizer Trim actuator removed had a Ballscrew Assembly with the LINEAR MOTION, LLC SB 7901708 incorporated.**Boeing Part Num ber**  **Skytronics, Inc. Part Number**  **Name**

10-61302-2 102J033-501 (.6250) (a) Stabilizer Ballscrew Assy

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 28 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Boeing Part Num**  **ber Skytronics, Inc.**  **Part Number Name** 

10-61302-2 102J033-501 (.6243) (a) Stabilizer Ballscrew Assy 10-61302-2 102J033-5 (a) Stabilizer Ballscrew Assy 10-61302-2 (b) 102J033-3 (a) (b) Stabilizer Ballscrew Assy 10-61302-1 102J033-1 (c) Stabilizer Ballscrew Assy 10-61302-1 102J033-1 (OS) (c) Stabilizer Ballscrew Assy (a) Incorporate Service Bulletin SKYTRONICS, Inc. SB 93004on these Ballscrew assemblies prior to installing the Horizontal Stabilizer Trim Actuator with the spare Ballscrew Assemblyon the airplane, if the Horizontal Stabilizer Trim Actuator removed had a Ballscrew Assembly with the SKYTRONICS, Inc. SB 93004 incorporated. (b) The Ballscrew Actuator Assy P/N 102J033-3 became BoeingP/N 10-61302-2 at the incorporation of Boeing Service Bulletin 737-27-1046 Revision 1 dated July, 1974. (c) The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting as given in Boeing Service Bulletin 737-27-1046 Revision 1. **B. Concurrent Requirements** None. **C. Reason** This service bulletin is being issued to maintain the frequency of the detailed inspection of the Horizontal Stabilizer Trim Actuator Ballscrew and Ball Nut as specified in the Maintenance Planning Document. This service bulletin also gives instructions to remove/replace and repair the Horizontal Stabilizer Trim Actuator if a damaged Ballscrew or Ball Nut is found. This service bulletin also adds the recommended intervals for repeat lubrication and overhaul. Also, this service bulletin gives recommended compliance time for incorporation of the suppliers service bulletins (service bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01, service bulletin LINEAR MOTION, LLC SB 7901708, and service bulletin SKYTRONICS, Inc. SB 93004). The UMBRA CUSCINETTI supplier service bulletin provides instructions to remove and replace the Ball Nut Tube Retainers on the 737 Horizontal Stabilizer Trim Actuator Ballscrew assembly with new Tube Retainers. The LINEAR MOTION supplier service bulletin provides instructions to remove and replace the Ball Deflectors and the Ball Return Guide Clamps on 737 Horizontal Stabilizer Trim Actuator Ballscrew assembly with new Ball Deflectors and Ball Return Guide Clamps. The SKYTRONICS supplier service bulletin provides instructions to remove and replace the

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 29 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**Return Tube Clamps on the 737 Horizontal Stabilizer Trim Actuator Ballscrew assembly with new Return Tube Clamps. The new parts installed will have sufficient stiffness to retain the load carrying balls in all known failure mode conditions. The changes given in this bulletin will reduce the probability of loss of the primary and secondary load paths of the Stabilizer Trim Actuator. Loss of primary and secondary load paths of the Stabilizer Trim Actuator could result in the loss of control of the airplane. This Service Bulletin also specifies the time for incorporation of the Boeing Service Bulletin 737-27-1046 Revision 1 (as applicable), dated April 5, 1974, if the service bulletin is not already incorporated. Boeing Service Bulletin 737-27-1046 Revision 1 applies to airplanes 737-100/200 with oil lubricators and provides instructions for removing the existing oil lubricators and installation of a grease fitting on the Stabilizer Trim Actuator Ball Nut. **NOTE:**The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting as given in Boeing Service Bulletin 737-27-1046 Revision 1. Remove these Stabilizer Trim Actuator Ballscrew Assemblies with Oil Lubricator and install 102J033-3 or 102J033-502 or Horizontal Stabilizer Trim Actuator Ballscrew Assembly. This service bulletin is being issued to maintain the frequency of the detailed visual inspection of the Horizontal Stabilizer Trim Actuator Ballscrew and Ball Nut as specified in the Maintenance Planning Document. This service bulletin also gives instructions to remove/replace and repair the Horizontal Stabilizer Trim Actuator if a damaged Ballscrew or Ball Nut is found. This service bulletin also adds the recommended intervals for repeat lubrication and overhaul. **NOTE:**Boeing also recommends that the Maintenance Planning Document (MPD) intervals be observed for the "Lubrication" and "Detailed Inspection" actions prior to compliance with this service bulletin. The "Lubrication" and "Detailed Inspection" done as given in this service bulletin satisfy the "Lubrication" and "Detailed Inspection" requirements given in Maintenance Planning Document" (MPD). Boeing Service Related Problem (SRP) 737CL-SRP-27-0153 is related to this bulletin. Revision 1 is sent to correct the work instructions for the HSTA name plate identification information in WORK PACKAGE 4 and to clarify some of the inspections necessary in WORK PACKAGE 1 and WORK PACKAGE 2. A note is also added in the compliance table to advise operators to do the lubrication task during the detailed inspection task. In addition, reference to the "Horizontal Stabilizer Gearbox End Play Test as given OHM 27-45-11" is added. This is because the Horizontal Stabilizer Gearbox Backlash Inspection is only given in the AMM for 737-600/700/800/900 airplane. The (OHM) Horizontal Stabilizer Gearbox End Play Test is a similar test and is applicable to all 737-100/200/300/400/500 airplane variants. 1. Paragraph 1.D., Description: Affected Maintenance Zones are added for each airplane group. 2. Paragraph 1.E., Compliance: Notes (a) and (b) are added to Table 1 and Table 2 to recommend operators to do a lubrication task during the detailed inspection task. 3. Paragraph 1.E., Compliance: Notice of Propose Rule Making 2007-NM-256-AD is added. 4. Paragraph 1.K., Publications Affected: Added Damage Tolerance Based Structural Inspection statement. 5. Paragraph 3.A., General Information: General Visual Inspection note added.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 30 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**6. Paragraph 3.B., Work Instructions: a. WORK PACKAGE 1: – Added some notes, added more data to some step instructions, deleted some unnecessary step instruction and correctly re-sequenced the steps. b. WORK PACKAGE 2: – Added some notes, added more data to some step instructions, deleted some unnecessary step instruction and correctly re-sequenced the steps. c. WORK PACKAGE 4: – Step 1.a. revised to reference SB 737-27A1278 WORK PACKAGE 4 instead of 737-27A1278 WORK PACKAGE 3. – Step 2.a. revised to reference SB 737-27A1278 WORK PACKAGE 4 instead of 737-27A1278 WORK PACKAGE 3. – Step 3.b. revised to reference SB 737-27A1278 WORK PACKAGE 4 instead of 737-27A1278 WORK PACKAGE 3. 7. FIGURE 1: Step 10, inspection for large amount of grease that exits the Ball Nut and note (a) are removed. 8. FIGURE 2: Step 10, inspection for large amount of grease that exits the Ball Nut and note (a) are removed. 9. FIGURE 7 sheet 2: Step 4, reference to Aircraft Maintenance Manual (AMM) removed and replaced with internal reference note (b). Also the step table note (b) is revised to reference Horizontal Stabilizer Gearbox End Play Test as given in OHM 27-45-11 instead of the Horizontal Stabilizer Gearbox Backlash inspection as given in AMM 27-41-81/606. 10. FIGURE 8 sheet 2: Step 4, reference to Aircraft Maintenance Manual (AMM) removed and replaced with internal reference note (b). Also the step table note (b) is revised to reference Horizontal Stabilizer Gearbox End Play Test as given in OHM 27-45-11 instead of the Horizontal Stabilizer Gearbox Backlash inspection as given in AMM 27-41-81/606. 11. FIGURE 9 sheet 2: Step 4, reference to Aircraft Maintenance Manual (AMM) removed and replaced with internal reference note (b). Also the step table note (b) is revised to reference Horizontal Stabilizer Gearbox End Play Test as given in OHM 27-45-11 instead of the Horizontal Stabilizer Gearbox Backlash inspection as given in AMM 27-41-81/606. **D. Description** Get access to the Horizontal Stabilizer Trim Actuator and do the procedures that follow below at the intervals shown in the compliance section. 1. DETAILED INSPECTION:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 31 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**– Do a detailed inspection for metal particles or corrosion products in the grease on the actuator Ball Nut and Ballscrew. Clean the actuator Ballscrew. Visually inspect the actuator Ball Nut and Ballscrew for damage, cracks, corrosion, and worn areas. Inspect for grease leakage. Inspect for lifted or damaged Ball Nut Tube Retainers (UMBRA CUSCINETTI, S.p.A Ballscrew Assemblies), or Ball Return Guide Clamps (LINEAR MOTION Ballscrew Assemblies), or Return Tube Clamps (SKYTRONICS, Ballscrew Assemblies). Inspect the external areas of the Stabilizer Trim Actuator, and the areas below the Stabilizer Trim Actuator, for loose ball bearings. Move the Horizontal Stabilizer to a different setting to get access to the Ballscrew area covered by the Ball Nut during the previous inspection. Repeat the inspections for the new exposed area of the ballscrew. Replace the Horizontal Stabilizer Trim Actuator before further flight if any of these conditions exist. – Do the Detailed Inspection as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 1 or WORK PACKAGE 2 (as applicable). LUBRICATE THE HORIZONTAL STABILIZER TRIM ACTUATOR: – Lubricate the Horizontal Stabilizer Trim Actuator Ballscrew, Ball Nut, and the upper and lower Gimbals. – Do the Lubrication as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 1 or WORK PACKAGE 2 (as applicable). REMOVE and REPAIR or REPLACE THE HORIZONTAL TRIM ACTUATOR: Remove/Replace the Horizontal Stabilizer Trim Actuator if damage is found as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 1 or WORK PACKAGE 2 (as applicable). **NOTE:**As an option, Operators can replace a damaged Horizontal Stabilizer Trim Actuator with a serviceable Stabilizer Trim Actuator that is not new or not overhauled. Before the next flight, do the Detailed Inspection and Lubrication for the replacement Stabilizer Trim Actuator as given in this service bulletin and do the End Play Test as given in OHM 27-45-11. After the installation follow the requirements of this service bulletin. 2. For airplanes with Horizontal Stabilizer Trim Actuator Ballscrew Assemblies with Oil Lubricators: a. CHECK the Horizontal Stabilizer Trim Actuator Ballscrew Assy Part Number. If you find Horizontal Stabilizer Trim Actuator Ballscrew Assemblies 102J033-1 (Boeing Part Number 10-61302-1) or 102J033-1 (OS) (Boeing Part Number 10-61302-1), remove and install Stabilizer Ballscrew Assy 102J033-3 (Boeing Part Number 10-61302-2) or 102J033-502 (Boeing Part Number 10-61302-7) as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 3. **NOTE:**The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting as given in Service Bulletin. The 102J033-3 (Boeing Part Number 10-61302-2) is an oil lubricated Horizontal Stabilizer Trim Actuator Ballscrew Assembly and operators have to incorporate Boeing Service

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 32 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**Bulletin 737-27-1046 Revision 1 and the Service Bulletin SKYTRONICS, Inc. SB 93004. The 102J033-502 (Boeing Part Number 10-61302-7) is a grease lubricated Horizontal Stabilizer Trim Actuator Ballscrew Assembly with reinforced Return Tube Clamps, and Operators do not have to incorporate Boeing Service bulletin 737-27-1046 Revision 1 and Service Bulletin SKYTRONICS, Inc. SB 93004. b. INCORPORATE BOEING SB 737-27-1046 Revision 1 as applicable: Incorporate SB 737-27-1046 Revision 1 as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 3. **NOTE:**Service Bulletin 737-27-1046 Revision 1 is applicable for some 737-100/200 airplanes with Ballscrew Oil Lubricators. This Service Bulletin provides instructions for the removal of the existing Oil Lubricators and the installation of a grease fitting on the Horizontal Stabilizer Trim Actuator Ball Nut. The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting. 3. INCORPORATE ONE OF THE FOLLOWING SUPPLIER SERVICE BULLETINS as given in Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 4: – Service Bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01, Rev 00, Dated December 21, 2004: Install the new Ball Nut Tube Retainers as given in this supplier service bulletin. – Service Bulletin LINEAR MOTION, LLC SB 7901708, Dated July 26, 2005: Install the new Ball Deflectors and Ball Return Guide Clamps as given in this supplier service bulletin. – Service Bulletin SKYTRONICS, Inc. SB 93004, Dated September 01, 2005: Install the new Return Tube Clamps as given in this supplier service bulletin. 4. REMOVE AND REPAIR/OVERHAUL THE HORIZONTAL STABILIZER TRIM ACTUATOR: – Remove and repair/overhaul the Horizontal Stabilizer Trim Actuator as given in Paragraph 3.B., Work Instructions, WORK PACKAGE 5. PLEASE SEND THE RESULTS FOR THE FAILED INSPECTIONS TO BOEING. Send your report to: BOEING COMMERCIAL AIRPLANES GROUP ATTENTION: MANAGER, SERVICE BULLETIN ENGINEERING P.O. BOX 3707, MAIL CODE 2H-36 SEATTLE, WA 98124-2207 USA Revision 1: No more work is necessary on airplanes changed as shown in the original issue of this service bulletin. However, Operators have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul as given in Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable. **NOTE:**The Operators that performed the initial Detailed Inspection, Lubrication, and Overhaul do not have to do another initial inspection, but have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator as given in Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable. The Operators that incorporated service bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 as given in WORK PACKAGE 4, have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator as given in Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 33 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**The Operators that did not incorporate Service Bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01, have to incorporate Service Bulletin UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 as given in WORK PACKAGE 4, and have to continue to do the repeat Detailed Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator as given in Paragraph 1.E., Compliance, Table 1 or Table 2 as applicable. The work in this service bulletin is done in the maintenance zone(s) given below. **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 7-2 737-200 **Group 1:**
**Affected Maintenance Zones Zone**  **Model** 702 737-300, 737-400, 737-500 **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 7-2 737-100, 737-200, 737-200C **Group 3:**
**Affected Maintenance Zones Zone**  **Model** 7-2 737-200, 737-200C **E. Compliance** Boeing recommends that the operators do this service bulletin at the time given in Table 1 or Table 2, as applicable. **NOTE:**Boeing also recommends that the Maintenance Planning Document (MPD) intervals be observed for the "Lubrication" and "Detailed Inspection" actions prior to compliance with this service bulletin. The "Lubrication" and "Detailed Inspection" done as given in this service bulletin satisfy the "Lubrication" and "Detailed Inspection" requirements given in Maintenance Planning Document" (MPD). Federal Aviation Administration (FAA) Notice of Proposed Rule Making FAA NPRM 2007-NM-256-AD, is related to this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 34 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group 1; Group 2, Configuration 1; Group 3:**  **Table 1 - Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator; Incorporation of UMBRA CUSCINETTI, S.p.A. 07322-27-01 Service Bulletin, LINEAR MOTION, LLC 7901708 Service**  **Bulletin, and SKYTRONICS, Inc. 93004 Service Bulletin**
**Notes Repeat Interval**  **Compliance Time (Whichever Occurs First)**  **Action Condition**  (a) 4,000 Flight Hours or 2 years (Whichever Occurs First). Within 4,000 Flight Hours or18 months from the last Detailed Inspection. Detailed Inspection inaccordance with Paragraph 3.B., Work Instructions Steps 1.e.and 1.o. WORK PACKAGE 1. Group 1, Group 2 Configuration 1, and Group 3 airplanes

(b) 2,000 Flight Hours or 1 year (Whichever Occurs First). Within 2,000 Flight Hours or1 Year from the last Lubrication.Lubricate in accordance with Paragraph 3.B., Work Instructions Step 1.p., WORK PACKAGE 1. 24,000 Flight Hours (Not to Exceed). Before the accumulation of 24,000 Flight Hours since thedate of issuance of the original standard airworthinesscertificate or the date of issuance of the original export certificate of airworthiness, or within 24,000 Flight Hours since last HSTA Overhaul. Horizontal Stabilizer Trim Actuator Overhaulin accordance with Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 5.

- Before the accumulation of 24,000 Flight Hours since thedate of issuance of the original standard airworthinesscertificate or the date of issuance of the original export certificate of airworthiness, or within 24,000 Flight Hours since last HSTA Overhaul. Incorporate ServiceBulletin UMBRA CUSCINETTI, S.p.A. SB07322-27-01, or Service Bulletin LINEAR MOTION, LLC SB 7901708, or Service Bulletin SKYTRONICS,Inc. SB 93004, as applicable, in accordance with Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 4.

- Before further flight Repair/Replace the Horizontal StabilizerTrim Actuator in accordance with Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 5. Group 1, Group 2 Configuration 1, and Group 3 airplaneswith damaged Horizontal Stabilizer Trim Actuator

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 35 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group 1; Group 2, Configuration 1; Group 3:**  **Table 1 - Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator; Incorporation of UMBRA CUSCINETTI, S.p.A. 07322-27-01 Service Bulletin, LINEAR MOTION, LLC 7901708 Service**  **Bulletin, and SKYTRONICS, Inc. 93004 Service Bulletin**
**Notes Repeat Interval**  **Compliance Time (Whichever Occurs First)**  **Action Condition**  (a) This task accomplishes a detailed inspection of the Horizontal Stabilizer Trim Actuator Ballscrew, Ball Nut, Ball Nut Tube Retainers and Return Tubes, and also accomplishes a detailed inspection of the lower and upper Gimbal and the attachment points. The detailed inspection done in accordance with the service bulletin partially satisfies the intent of the task in accordance with 737-200 MPD Volume 1 Section 4 Item Number 4-27-06, or 737-300/400/500 MPD Volume 1 Section 6, Item Number B27-00- 00-F. You must accomplish the detailed inspection of the Horizontal Stabilizer Trim actuator as given in this service bulletin to establish and stay compliant with this service bulletin. (b) Accomplishment of this task satisfies the intent of the task in accordance with 737-200 MPD Volume 1 Section 3 Item Number 3-05-01, or 737-300/400/500 MPD Volume 1 Section 6, Item Number B12- 22-41-3A. However, you must accomplish this task as given in this service bulletin to establish and stay compliant with this service bulletin. **Group 2, Configuration 2: Table 2 - Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator; Incorporation**  **of 737-27-1046 Boeing Service Bulletin, and SKYTRONICS, Inc. 93004 Service Bulletin**
**Notes Repeat Interval**  **Compliance Time (Whichever Occurs First)**  **Action Condition**  (d) 2,000 Flight Hours or 1 year (Whichever occurs first). Within 2,000 Flight Hoursor 1 year from the last inspection.Detailed Inspection in accordance with Accomplishment Instruction, Paragraph 3.B., Work Instructions, Steps 1.e. and 1.o., WORK PACKAGE 2.Group 2, Configuration 2 airplanes

(e) 500 Flight Hours or 2months (whichever occurs first). Within 500 Flight Hours or2 months from the last Lubrication. Lubricate in accordance with Accomplishment Instruction,Paragraph 3.B., Work Instructions, Step 1.p., WORK PACKAGE 2. 20,000 Flight Hours (Not To Exceed). Before the accumulation of 20,000 Flight Hours since the date of issuance of theoriginal standard airworthiness certificate or the date of issuance of the originalexport certificate of airworthiness, or within 20,000Flight Hours since last HSTA overhaul. Horizontal Stabilizer TrimActuator Overhaul in accordance with Accomplishment Instructions, Paragraph 3.B., Work Instructions, WORK PACKAGE 5.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 36 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group 2, Configuration 2:**  **Table 2 - Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator; Incorporation of 737-27-1046 Boeing Service Bulletin, and SKYTRONICS, Inc. 93004 Service Bulletin** 
**Notes Repeat Interval**  **Compliance Time (Whichever Occurs First)**  **Action Condition** 

- Before further flight Repair/Replace the Horizon- tal Stabilizer Trim Actuatorin accordance with Accomplishment Instructions,Paragraph 3.B., Work Instructions, WORK PACKAGE 5.Group 2 Configuration 2 airplanes withdamaged Horizontal Stabilizer Trim Actuator (a)

- Before the accumulation of 20,000 Flight Hours since the date of issuance of theoriginal standard airworthiness certificate or the date of issuance of the originalexport certificate of airworthiness, or within 20,000Flight Hours since last HSTA overhaul. Remove the Stabilizer Ballscrew Assy 102J033-1or 102J033-1 (OS) and install Stabilizer Ballscrew Assy 102J033-3 or 102J033-502 in accordance with Accomplishment Instructions,Paragraph 3.B., Work Instructions, WORK PACKAGE 3.Group 2 Configuration 2 airplanes with Stabilizer Trim Actuator Ballscrew Assy 102J033-1 or 102J033-1 (OS) installed on the airplane. (a) (b) (c) - Before the accumulation of 20,000 Flight Hours since the date of issuance of theoriginal standard airworthiness certificate or the date of issuance of the originalexport certificate of airworthiness, or within 20,000Flight Hours since last HSTA overhaul. Incorporate Boeing ServiceBulletin 737-27-1046 Revision 1 in accordance withAccomplishment Instructions, Paragraph 3.B., WorkInstructions, WORK PACKAGE 3.Group 2, Configuration 2 airplanes with Horizontal Stabilizer Trim Actuator Ballscrew Assywith Oil Lubricators

(a)

- Before the accumulation of 20,000 Flight Hours since the date of issuance of theoriginal standard airworthiness certificate or the date of issuance of the originalexport certificate of airworthiness, or within 20,000Flight Hours since last HSTA overhaul. Incorporate SKYTRONICS, Inc. SB 93004 in accordancewith Accomplishment Instructions, Paragraph 3.B., WorkInstructions, WORK PACKAGE 4.Group 2, Configuration 2 airplanes

(a) The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting in accordance with Boeing Service Bulletin 737-27-1046 Revision 1. If you find Stabilizer Ballscrew Assemblies 102J033-1 or 102J033-1 (OS) installed on the airplane, remove and install 102J033- 3 or 102J033-502 Horizontal Stabilizer Trim Actuator Ballscrew Assembly.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 37 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Group 2, Configuration 2:**  **Table 2 - Inspection, Lubrication, and Overhaul of the Horizontal Stabilizer Trim Actuator; Incorporation of 737-27-1046 Boeing Service Bulletin, and SKYTRONICS, Inc. 93004 Service Bulletin** 
**Notes Repeat Interval**  **Compliance Time (Whichever Occurs First)**  **Action Condition**  (b) Airplanes with Horizontal Stabilizer Trim Actuator Ballscrew Assemblies with Oil Lubricators can bechanged to Trim Actuators Ballscrew Assemblies with grease lubricator by removing the existing Oil Lubricator Reservoirs and installing a Grease Fitting in accordance with Boeing Service Bulletin 737-27- 1046 Revision 1, dated April 05, 1974.(c) After you incorporate Boeing Service Bulletin 737-27-1046 Revision 1 (after you install the grease lubricator as given in SB 737-27-1046) the airplane will belong to Group 1 Configuration 1 airplanes. Use the Detailed Inspection, Lubrication, and Overhaul intervals given in Table 1. (d) This task accomplishes a detailed inspection of the Horizontal Stabilizer Trim Actuator Ballscrew, Ball Nut, Ball Nut Tube Retainers and Return Tubes, and also accomplishes a detailed inspection of the lower and upper Gimbal and the attachment points. The detailed inspection done in accordance with the service bulletin partially satisfies the intent of the task in accordance with 737-200 MPD Volume 1 Section 4, Item Number 4-27-06. You must accomplish the detailed inspection of the Horizontal Stabilizer Trim Actuator as given in this service bulletin to establish and stay compliant with this service bulletin. (e) Accomplishment of this task satisfies the intent of the task in accordance with 737-200 MPD Volume 1 Section 3, Item Number 3-05-01. However you must accomplish this task as given in this service bulletin to establish and stay compliant with 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 for each airplane to do a detailed inspection, to lubricate, and to replace the horizontal stabilizer trim actuator. 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 examine the work — Time to cure the materials — Time to make the parts — Time to find the tools.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 38 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Elapsed Hours**  **Task-Hours Number of Per-**  **sons Task** 

1.25 1.25 1 Open Access 2.0 4.0 2 Detailed Inspection 1.25 2.5 2 Lubrication 4.0 8.0 2 Replace Stabilizer Trim Actuator (b) 1.25 1.25 1 Close Access 1.0 2.0 2 Test 6.75 11.0 TOTAL FOR EACH AIRPLANE (a) (a) Total hours does not include actuator replacement.(b) Hours are for replacement only, additional time required for Stabilizer Trim Actuator overhaul. **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data: a. Engineering Change Memo PRR 35005-261RS b. Boeing Service Bulletin 737-27-1046 c. Boeing Service Related Problem (SRP) 737CL-SRP-27-0153 d. Component Maintenance Manual (CMM) 27-41-81, 27-45-11, 27-45-12 e. Federal Aviation Administration (FAA) Notice of Proposed Rule Making 2007-NM-256-AD f. Overhaul Manual (OHM) 27-45-11 g. Standard Overhaul Practices Manual (SOPM) 20-50-10 h. 737-100/200 Aircraft Maintenance Manual (AMM) 12-22-41, 27-41-121, 27-41-81 i. 737-200 Maintenance Planning Data (MPD) Volume 1Section 1, Volume 1Section 3, Volume 1Section 4 j. 737-300/400/500 Aircraft Maintenance Manual (AMM) 12-22-41, 27-41-81

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 39 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**k. 737-300/400/500 Maintenance Planning Data (MPD) Volume 1Section 4, Volume 1Section 6 l. LINEAR MOTION, LLC Service Bulletin 7901708 m. SKYTRONICS, Inc. Service Bulletin 93004 n. UMBRA CUSCINETTI, S.p.A. Service Bulletin 07322-27-01 o. LINEAR MOTION, LLC Component Maintenance Manual (CMM) 27-41-01 p. SKYTRONICS, Inc. Component Maintenance Manual (CMM) 27-40-03 q. UMBRA CUSCINETTI, S.p.A. Component Maintenance Manual (CMM) 27-41-01 a. Engineering Change Memo PRR 35005-261RS b. Boeing Service Bulletin 737-27-1046 c. Boeing Service Related Problem (SRP) 737CL-SRP-27-0153 d. Component Maintenance Manual (CMM) 27-41-81, 27-45-11, 27-45-12 e. Federal Aviation Administration (FAA) Notice of Proposed Rule Making 2007-NM-256-AD f. Overhaul Manual (OHM) 27-45-11 g. Standard Overhaul Practices Manual (SOPM) 20-50-10 h. 737-100/200 Aircraft Maintenance Manual (AMM) 12-22-41, 27-41-121, 27-41-81 i. 737-200 Maintenance Planning Data (MPD) Volume 1Section 1, Volume 1Section 3, Volume 1Section 4 j. 737-300/400/500 Aircraft Maintenance Manual (AMM) 12-22-41, 27-41-81 k. 737-300/400/500 Maintenance Planning Data (MPD) Volume 1Section 4, Volume 1Section 6 l. LINEAR MOTION, LLC Service Bulletin 7901708 m. SKYTRONICS, Inc. Service Bulletin 93004 n. UMBRA CUSCINETTI, S.p.A. Service Bulletin 07322-27-01 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 40 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT K. Publications Affected**  1. Publications: **Chapter-Section Publication**  737-300/400/500 AMM 12-22-41, 737-300/400/500 AMM 27-41-81 737 Maintenance Manual

CMM 27-45-11 737 Component Maintenance Manual Section 1 737-100/200 Maintenance Planning Docu- ment (MPD) Section 6 737-300/400/500 Maintenance Planning Document (MPD) 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 Illustration Parts Catalog (IPC) for the Interchangeable parts.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 41 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 42 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None. **B. Industry Support Information** Boeing warranty remedies are available for 737 airplanes in warranty as of June 14, 2001. For man-hour reimbursement for airplanes in warranty as of that date, send a warranty claim to Boeing Commercial Airplanes Group - Warranties. The parts for airplanes in warranty as of that date will be supplied at no charge. Send a purchase order for the parts to Boeing Spares. Please refer to this service bulletin number and reference the airplane variable number in your purchase order. **C. Parts Necessary For Each Airplane** 1. Kits/Parts: None. 2. Parts and Materials Supplied by the Operator:
**Notes Name**  **QTY Part Number / Specifi-**  **cation** (a) Kit, 737 HSTA Clamp

- 7901976 (b) Tube Clamp Kit

- 102C238-1 Recommended (c) Grease As Neces- sary BMS 3-33

Alternate to BMS 3-33 Grease As Neces- sary MIL-G-23827 General Purpose Oil As Neces- sary MIL-L-7870 (c) Protective Enamel (Clear), Hydraulic Fluid ResistantAs Necessary BMS 10-60, Type 2, Clear or equivalent (d) Ink or Paste Ink As Neces- sary Permanent Marking Material (a) You need this kit if you incorporate service bulletin LINEAR MOTION, LLC SB 7901708. Order the kit from Boeing Spares. (b) You need this part if you incorporate service bulletin SKYTRONICS, Inc. SB 93004. Order the number of parts required as given in the Skytronics, Inc. service bulletin from Boeing Spares. (c) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (d) Refer to SOPM 20-50-10 for the list of permanent marking materials.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 43 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**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: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 44 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:**1. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 2. Obey all of the warnings and cautions given in the specified manual sections. 3. The work instructions are divided into work packages. Task Hours and Elapsed Hours for each package are given in Paragraph 1.G., Manpower. You can do each work package independently. 4. Use the approved fastener and process material substitutions in accordance with 737 SRM, Chapter 51. Alternate fasteners are listed in 737 SRM Chapter 51 and Boeing Drawing 65-88700. 5. 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. 6. 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 ensure visual access to all surfaces in the inspection area. This level of inspection is made under normal 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. 7. 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. 8. Operators will find the term "Stabilizer Trim Actuator" in the Airplane Maintenance Manual documents. The "Stabilizer Trim Actuator" includes the Ball Nut, Jackscrew, and Jackscrew Gearbox. The term "Jackscrew" called out in the Airplane Maintenance Manual documents is referred to as "Ballscrew" in this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 45 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT B. WORK INSTRUCTIONS**  **WORK PACKAGE 1 (GROUP 1, GROUP 2 CONFIGURATION 1, and GROUP 3 Airplanes): Detailed Inspection and Lubrication of the Horizontal Stabilizer Trim Actuator Ballscrew, Ball Nut, and**  **attachment (Gimbal) fittings** 1. Refer to Paragraph 1.E., Compliance, Table 1, for the interval at which the Detailed Inspection and Lubrication of Stabilizer Trim Actuator Ballscrew, Ball Nut, and attachment fittings (Gimbal Fittings) need to be accomplished/repeated. a. Get access to the horizontal Stabilizer Trim Actuator assembly through service access door 3701. Refer to 737-200 MPD Volume 1 Section 1 or 737-300/400/500 MPD Volume 1 Section 4, Access Doors and Panels. b. Set the STAB TRIM MAIN CUTOUT switch S272, on the control stand, to the CUTOUT position. c. Set the AUTOPILOT CRUISE TRIM CUTOUT switch S149, on the control stand, to the CUTOUT position. d. Open these circuit breakers shown below and attach the DO-NOT-CLOSE tags: For Group 1 airplanes:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2, B13

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2, B11

C00849 STABILIZER TRIM SERVO P18-0, A1

For Group 2 Configuration 1, and Group 3 airplanes:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 46 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**e. Do a detailed inspection of the Horizontal Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 Airplanes in accordance with FIGURE 1. For Group 1 Configuration 2 airplanes in accordance with FIGURE 2. (1) Do a detailed inspection of all attachment points of the Lower and Upper Gimbal for cracks and other damage. Inspect the areas around the holes and bushing. Make sure that the Stabilizer Trim Actuator is correctly attached to the airplane structure. If any damage is found, repair or replace the damaged parts. Refer to 737-100/200 AMM 27-41-81 or 737-300/400/500 AMM 27-41-81 and CMM 27-45-12 as an accepted procedure. (2) Do a general visual inspection of the area under, on, and around the Stabilizer Trim Actuator to see if grease is escaping from Ball Nut. Large amounts of grease present around the Stabilizer Trim Actuator indicate that a faulty seal or lifted return tube may be present on the Ball Nut. If a large amount of grease is present due to a faulty seal or lifted/leaking return tube, repair/replace the Stabilizer Trim Actuator in accordance with FIGURE 7 for Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 Airplanes and in accordance with FIGURE 8 for Group 1 Configuration 2 airplanes. (3) Do a detailed inspection of the grease on and around the Ballscrew and Ball Nut for existence of metallic particles, other solid particles, and corrosion products in the grease. If metallic particles, or other solid particles, or corrosion products are found in the grease, Repair/Replace the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 Airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 Airplanes in accordance with FIGURE 8. **NOTE:**If visible metallic particles are observed in the grease there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew actuator can happen, but this will not release visible metallic particles in the grease. (4) Check if any of the Ball Nut bearings are found in the vicinity of the Ball Nut, on the Ballscrew, or directly below the Stabilizer Trim Actuator. If Ball Nut ball bearings are found Repair/Replace the Horizontal Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. **NOTE:**The Ball Nut ball bearings used inside the 737 Ball Nut are approximately 0.218 inch (5.6mm) in diameter.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 47 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**(5) Remove any old grease and dirt from the Ballscrew threads by wiping them with a clean, dry, non-abrasive cloth. (6) Do a detailed inspection of the Ball Nut Tube Retainers for deformation and corrosion or lifted Return Tubes. If the Ball Nut Tube Retainers have deformation or corrosion or the Return Tubes are lifted, Repair/Replace the stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. **NOTE:**Operators will find in the applicable Component Maintenance Manuals (CMM) for Ballscrew Assembly the following terms: Ball Nut "Tube Retainers" (for UMBRA CUSCINETTI, S.p.A. Ballscrew Assemblies), or BallNut "Return Tube Covers" (LINEAR MOTION, LLC), or Ball Nut "Return Tube Clamps" (SKYTRONICS, Inc.). The Term "Ball Nut Tube Retainers" will be used throughout the Accomplishment Instructions. (7) Do a detailed inspection of the Ballscrew for the following problems: (a) Inspect the Ballscrew threads for cross-threading, distortion, or stripping. If you find any of these conditions Repair/Replace the Stabilizer Trim Actuator in accordance with: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8 (b) Check the Ballscrew for metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, and worn areas in the Ballscrew threads. If metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, or worn areas in the Ballscrew threads is observed, repair/replace (as necessary) the Stabilizer Trim actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7 For Group 1 Configuration 2 airplanes in accordance with FIGURE 8 (c) Check for obvious differences in thread shape between thread grooves in the lower, middle, and upper portions of the Ballscrew. If obvious differences in thread shape between thread grooves in the lower, middle, and upper portions of the Ballscrew are observed repair/replace (as necessary) the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. f. Remove the DO-NOT-CLOSE tags and close the circuit breakers shown below: For Group 1 airplanes:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 48 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Notes**  **Circuit Breaker Name**  **Location (Panel, Position)**  C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2, B13

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2, B11

C00849 STABILIZER TRIM SERVO P18-0, A1

For Group 2 Configuration 1, and Group 3 airplanes:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

g. Set the STAB TRIM MAIN CUTOUT switch, S272, on the control stand, to the NORMAL position. h. Push and hold the Stabilizer Trim Control switches on the Captain's Control Wheel (NOSE UP or NOSE DOWN) to move the ballscrew to another location other than the current setting. i. Make sure the operation is smooth and there is no unusual noise. j. Set the STAB TRIM MAIN CUTOUT switch, S272 on the control stand, to the CUTOUT position. k. Make sure that the AUTOPILOT CRUISE TRIM CUTOUT switch S149, on the control stand, is SET to the CUTOUT position. l. Open this circuit breakers shown below and attach the DO-NOT-CLOSE tags: For Group 1 airplanes:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2, B13

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 49 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Notes**  **Circuit Breaker Name**  **Location (Panel, Position)**  C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2, B11

C00849 STABILIZER TRIM SERVO P18-0, A1

For Group 2 Configuration 1, and Group 3 airplanes:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

m. Do a detailed inspection of the grease on the newly exposed area of the Ballscrew for metallic particles, other solid particles, and corrosion products in the grease. If metallic particles, or other solid particles, or corrosion products are found in the grease Repair/Replace the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. **NOTE:**If visible metallic particles are observed in the grease there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew actuator can happen, but this will not release visible metallic particles in the grease. n. Remove any grease from the newly exposed portion of the Ballscrew threads by wiping them with a clean, dry, non abrasive cloth. o. Do a detailed inspection of the newly exposed Ballscrew for the following problems: (1) Inspect the Ballscrew threads for cross-threading, distortion, or stripping. If you find any of these conditions Repair/Replace the Stabilizer Trim actuator in accordance with: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 50 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. (2) Check the Ballscrew for metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, and worn areas in the Ballscrew threads. If metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, or worn areas in the Ballscrew threads is observed, repair/replace (as necessary) the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 in accordance with FIGURE 7. For Group 1 Configuration 2 airplane in accordance with FIGURE 8. (3) Check for obvious differences in the thread shape between thread grooves in the lower, middle, and upper portions of the Ballscrew. If obvious differences in thread shape between thread grooves in the lower, middle, and upper portions of the Ballscrew are observed, repair/replace (as necessary) the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. p. Apply grease (Lubricate) the Ballscrew and Ball Nut: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 4. For Group 1 Configuration 2 airplanes in accordance with FIGURE 5. Apply the grease slowly until clean, new, fresh grease exits through the grease vent. If clean, new, fresh grease fails to exit the grease vent OR the upper seal, repair/replace the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. (1) Inspect if grease exits the Ball Nut through Upper Seal, Lower Seal and around the Tube Retainer areas: (a) Clean, new fresh grease, that exits from the upper seal is also an acceptable indication of proper lubrication of the Ball Nut. (b) Small amounts of grease may exit the lower seal and is considered acceptable as long as the general visual inspection of the under, on, and around the Stabilizer Trim Actuator given in WORK PACKAGE 1 step 1.e.2 was found satisfactory. (c) Small amount of grease may exit the ball nut through the Tube Retainer areas (from the Return Tubes). If small amount of grease is observed around the Tube Retainer do a detailed inspection of the Ball Nut Tube Retainers for deformation and corrosion or lifted Return Tubes. If the Ball Nut Tube Retainers have deformation or corrosion Repair/Replace (as necessary) the Stabilizer Trim Actuator:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 51 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. If no damage of the Tube Retainers is found, the condition is acceptable. If large amount of grease exits through the Tube Retainer areas, the Return Tubes may be lifted and the Stabilizer Trim Actuator must be repaired or replaced: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. (2) Inspect the grease that exits the Ball Nut for indication of metallic particles, discolored water, rust, or other solid particles. If any of these conditions exist Repair/Replace the Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplanes in accordance with FIGURE 7. For Group 1 Configuration 2 airplanes in accordance with FIGURE 8. **NOTE:**If visible metallic particles are observed in the grease there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew Actuator can happen but this will not release visible metallic particles in the grease. 2. Remove the DO-NOT-CLOSE tags and close the circuit breakers shown below: For Group 1 airplanes:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2, B13

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2, B11

C00849 STABILIZER TRIM SERVO P18-0, A1

For Group 2 Configuration 1, and Group 3 airplanes:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 52 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Notes**  **Circuit Breaker Name**  **Location (Panel, Position)**  C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

3. Close the service access door 3701. Refer to 737-200 MPD Volume 1 Section 1 or 737-300/400/500 MPD Volume 1 Section 4, Access Doors and Panels. 4. Put the airplane back to a serviceable condition. **NOTE:**Make sure that you set the STAB TRIM MAIN CUTOUT to the serviceable position. **WORK PACKAGE 2 (GROUP 2 CONFIGURATION 2 Airplanes): Detailed Inspection and Lubrication of the Horizontal Stabilizer Trim Actuator Ballscrew, Ball Nut, and attachment (Gimbal) fittings**  1. Refer to Section 1.E., Compliance, Table 2, for the interval at which the Detailed Inspection and Lubrication of Stabilizer Trim Actuator Ballscrew, Ball Nut, and attachment fittings (Gimbal Fittings) need to be accomplished/repeated. a. Get access to the Horizontal Stabilizer Trim Actuator assembly through service access door 3701. Refer to 737-200 MPD Volume 1 Section 1, Access Doors and Panels. b. Set the STAB TRIM MAIN CUTOUT switch S272, on the control stand, to the CUTOUT position. c. Set the AUTOPILOT CRUISE TRIM CUTOUT switch S149, on the control stand, to the CUTOUT position. d. Open this circuit breakers shown below and attach the DO-NOT-CLOSE tags:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 53 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**e. Do a detailed inspection of the Horizontal Stabilizer Trim Actuator in accordance with FIGURE 3: (1) Do a detailed inspection of all attachment points of the Lower and Upper Gimbal for cracks and other damage. Inspect the area around the holes and bushing. Make sure that the Stabilizer Trim Actuator is correctly attached to the airplane structure. If any damage is found, repair or replace the damaged part. Refer to 737-100/200 AMM 27-41-81 and CMM 27-45-12 as an accepted procedure . (2) Do a detailed inspection of the oil on and around the Ballscrew and Ball Nut for existence of metallic particles, other solid particles, and corrosion products in the oil. If metallic particles, or other solid particles, or corrosion products are found in the oil, Repair/Replace the Stabilizer Trim Actuator in accordance with FIGURE 9. **NOTE:**If visible metallic particles are observed in the oil there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew actuator can happen, but this will not release visible metallic particles in the oil. (3) Check if any of the Ball Nut bearings are found in the vicinity of the Ball Nut, on the Ballscrew, or directly below the Stabilizer Trim Actuator. If Ball Nut bearings are found Repair/Replace the Horizontal Stabilizer Trim Actuator in accordance with FIGURE 9. **NOTE:**The Ball Nut bearings used inside the 737 Ball Nut are approximately 0.218 inch (5.6 mm) in diameter. (4) Remove any old oil and dirt from the Ballscrew threads by wiping them with a clean, dry, non-abrasive cloth. (5) Do a detailed inspection of the Ball Nut Tube Retainers for deformation and corrosion or lifted return tubes. If the Ball Nut Tube Retainers have deformation or corrosion or the Return Tubes are lifted, Repair/Replace the Stabilizer Trim Actuator in accordance with FIGURE 9. (6) Do a detailed inspection of the Ballscrew for the following problems in accordance with FIGURE 3. (a) Inspect the Ballscrew threads for cross-threading, distortion, or stripping. (b) Check the Ballscrew for metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks and worn areas in the Ballscrew threads. If metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, or worn areas in the Ballscrew threads is observed, repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 9. (c) Check for obvious differences in thread shape between thread grooves in the lower, middle, and upper portions of the Ballscrew. If obvious differences in thread shape between thread grooves in the lower, middle, and upper portions of the Ballscrew is observed, repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 9. f. Remove the DO-NOT-CLOSE tags and close the circuit breakers shown below:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 54 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT Notes**  **Circuit Breaker Name**  **Location (Panel, Position)**  C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

g. Set the STAB TRIM MAIN CUTOUT switch S272, on the control stand, to the NORMAL position. h. Push and hold the Stabilizer Trim Control switches on the Captain's Control Wheel (NOSE UP or NOSE DOWN) to move the ballscrew to another location other than the current setting. i. Make sure the operation is smooth and there is no unusual noise. j. Set the STAB TRIM MAIN CUTOUT switch S272, on the control stand, to the CUTOUT position. k. Make sure that the AUTOPILOT CRUISE TRIM CUTOUT switch S149, on the control stand, is SET to the CUTOUT position. l. Open these circuit breakers shown below and attach the DO-NOT-CLOSE tags:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

m. Do a detailed inspection of the oil on the newly exposed area of the Ballscrew for metallic particles, other solid particles, and corrosion products in the oil. If metallic particles, or other solid particles, or corrosion products are found in the oil Repair/Replace the Stabilizer Trim Actuator in accordance with FIGURE 9. **NOTE:**If visible metallic particles are observed in the oil there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew actuator can happen, but this will not release visible metallic particles in the oil.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 55 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**n. Remove any oil from the newly exposed portion of the Ballscrew threads by wiping them with a clean, dry, non abrasive cloth. o. Do a detailed inspection of the newly exposed area of the Ballscrew for the following problems in accordance with FIGURE 3. (1) Inspect the Ballscrew threads for cross-threading, distortion, or stripping. (2) Check the Ballscrew for metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, and worn areas in the Ballscrew threads. If metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, or worn areas in the Ballscrew threads is observed, remove, inspect, repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 9. (3) Check for obvious differences in the thread shape between thread grooves in the lower middle, and upper portions of the Ballscrew. If obvious differences in thread shape between thread grooves in the lower, middle, and upper portion of the Ballscrew are observed, remove, inspect, repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 9. p. Apply grease (Lubricate) and fill oil reserver in accordance with FIGURE 6. 2. Remove the DO-NOT-CLOSE tags and close the circuit breakers shown below:
**Notes Circuit Breaker**  **Name Location (Panel,**  **Position)** C00207 FLIGHT CON- TROL STAB TRIM CONT P6-2

C00840 FLIGHT CON- TROL STAB TRIM ACTUATOR P6-2

C00849 STABILIZER TRIM SERVO P6-2

3. Close the service access door 3701. Refer to 737-200 MPD Volume 1 Section 1, Access Doors and Panels. 4. Put the airplane back to a serviceable condition. **NOTE:**Make sure that you set the STAB TRIM MAIN CUTOUT to the serviceable position. **WORK PACKAGE 3 (GROUP 2, CONFIGURATION 2 AIRPLANES): Incorporate Boeing Service Bulletin 737-27-1046, Revision 1, dated April 05, 1974 (If service bulletin is not already**  **incorporated)** 1. For airplane with Horizontal Stabilizer Trim Actuator Ballscrew Assemblies with Oil Lubricators, remove the existing Oil Lubricator Reservoirs and install a Grease Fitting in accordance with Boeing Service Bulletin 737-27-1046 Revision 1, dated April 05, 1974.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 56 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**a. If you find the Stabilizer Ballscrew Assy 102J033-1 or 102J033-1 (OS) installed on the airplane, remove and install Stabilizer Ballscrew Assy 102J033-3 or 102J033-502. If you install a Stabilizer Ballscrew Assy 102J033-3 make sure that you incorporate Boeing Service Bulletin 737-27-1046 Revision 1, dated April 05, 1974 (if not already incorporated), before you install this ballscrew assembly on the airplane. **NOTE:**The Horizontal Stabilizer Trim Actuator Ballscrew Assembly 102J033-1 or 102J033-1 (OS) with Oil Lubricator can not be reworked to a Horizontal Stabilizer Trim Actuator Ballscrew Assembly with grease lubrication fitting as given in Service Bulletin 737-27-1046. **NOTE:**The Horizontal Stabilizer Trim Actuators with Oil Lubricators reworked to Horizontal Stabilizer Trim Actuator with grease lubrication fittings in accordance with Service Bulletin 737-27-1046 Revision 1, have to incorporate the SKYTRONICS, Inc. SB 93004 Service Bulletin, Dated September 01, 2005 in accordance with Work Package 4. **WORK PACKAGE 4 (ALL AIRPLANES): Rework the Stabilizer Trim Actuator Ballscrew assembly** 1. For airplane with UMBRA CUSCINETTI Ballscrew Assemblies, install new Ball Nut Tube Retainers in accordance with UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 Service Bulletin, Rev 00, Dated December 21, 2004. a. After you incorporate UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 Service Bulletin, hand letter with a permanent ink or paste ink, in the area adjacent to the HSTA name plate (gear box area) the following: "UMBRA CUSCINETTI, S.p.A. SB 07322-27-01 IS INCORPORATED ON THIS HSTA IN ACCORDANCE WITH SB 737-27A1278, WORK PACKAGE 4" Apply BMS 10-60, Type 2, Clear, over the marking, to protect the marking from hydraulic fluid. Refer to SOPM 20-50-10 as an accepted procedure for the marking process and marking materials. 2. For airplane with LINEAR MOTION Ballscrew Assemblies, install new Ball Deflectors and Ball Return Guide Clamps in accordance with LINEAR MOTION, LLC SB 7901708 Service Bulletin, Dated July 26, 2005. a. After you incorporate LINEAR MOTION, LLC SB 7901708 Service Bulletin, hand letter with a permanent ink or paste ink, in the area adjacent to the HSTA name plate (gear box area) the following: "LINEAR MOTION, LLC SB 7901708 IS INCORPORATED ON THIS HSTA IN ACCORDANCE WITH SB 737-27A1278, WORK PACKAGE 4" Apply BMS 10-60, Type 2, Clear, over the marking, to protect the marking from hydraulic fluid. Refer to SOPM 20-50-10 as an accepted procedure for the marking process and marking materials. 3. For airplane with SKYTRONICS Ballscrew Assemblies, install the new Return Tube Clamps in accordance with SKYTRONICS, Inc. SB 93004 Service Bulletin, Dated September 01, 2005.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 57 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**a. If you find the Stabilizer Ballscrew Assy 102J033-1 or 102J033-1 (OS) installed on the airplane remove and install Stabilizer Ballscrew Assy 102J033-502 or equivalent. If you install a Stabilizer Ballscrew Assy 102J033-3 make sure to incorporate SB 737-27-1046 before you install the Stabilizer Ballscrew Assy on the airplane. b. After you incorporate SKYTRONICS, Inc. SB 93004 Service Bulletin, hand letter with a permanent ink or paste ink, in the area adjacent to the HSTA name plate (gear box area) the following: "SKYTRONICS, Inc. SB 93004 IS INCORPORATED ON THIS HSTA IN ACCORDANCE WITH SB 737-27A1278, WORK PACKAGE 4" Apply BMS 10-60, Type 2, Clear, over the marking, to protect the marking from hydraulic fluid. Refer to SOPM 20-50-10 as an accepted procedure for the marking process and marking materials. **WORK PACKAGE 5 (ALL AIRPLANES): Remove the Stabilizer Trim Actuator for Repair/Overhaul** 1. Remove and Repair/Overhaul the Horizontal Stabilizer Trim Actuator: For Group 1 Configuration 1, Group 2 Configuration 1, and Group 3 airplane in accordance with FIGURE 7. For Group 1 Configuration 2 airplane in accordance with FIGURE 8. For Group 2 Configuration 2 airplane in accordance with FIGURE 9. Repeat the Overhaul as given in Paragraph 1.E., Compliance, Table 1 or Table 2, as applicable. **NOTE:**Refer to 737-100/200 AMM 27-41-81 or 737-300/400/500 AMM 27-41-81 for instructions to remove the Horizontal Stabilizer Trim Actuator. Refer to the applicable Component Maintenance Manual: UMBRA CUSCINETTI, S.p.A. CMM 27-41-01, or LINEAR MOTION LLC CMM 27-41-01, or SKYTRONICS Inc CMM 27-40-03 and CMM 27-45-11 for repairs of the Horizontal Stabilizer Trim Actuator components.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1: January 07, 2010 58 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 1-2, Configuration 1; Group 3.** 

**FIGURE 1: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND THE ATTACHMENT FITTINGS- (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION**  **1, AND GROUP 3 AIRPLANES) (SHEET 1 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 59 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT FIGURE 1: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**  **BALL NUT, AND THE ATTACHMENT FITTINGS- (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES)**  **(SHEET 2 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 60 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT FIGURE 1: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**  **BALL NUT, AND THE ATTACHMENT FITTINGS- (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES)**  **(SHEET 3 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 61 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** (a)

- Stabilizer Trim Actu- ator attachment points Inspect 1

Do a general visual inspection to see if large amount of grease exits the Ball Nut. (b) - Area Under, On, and Around Stabilizer Trim Actuator Inspect 2

(c) (d)

- Grease Inspect 3 for escaped Ball Nut ball bearings. (e)

- Ballscrew and Ball Nut, Trim Actuator Housing and area below Stabilizer Trim Actuator Inspect 4

from Ballscrew threads by wiping with a clean, dry, non-abrasive cloth. - Grease Remove 5 Do a detailed inspection for deformation and corrosion or lifted return tubes. Ball Nut and Ball Nut Tube Retainers Inspect 6 (f)

- Ballscrew Inspect 7 to another location.

- Ballscrew Move 8 for existence of metal particles or other debris. (b) (c) - Ballscrew and Ball Nut Inspect 9 (f)

- Ballscrew Inspect 10 (a) Do a detailed inspection of the lower and upper gimbal for cracks and other damage. Inspect the area around the bushing. Make sure that the Stabilizer Trim Actuator is correctly attached to the airplane structure. (b) Large amount of grease present around the ball-screw indicate that a faulty seal or raised Ball Nut return tubes may be present. (c) Metallic particles in grease may be indication of degradation of the balls in the Ball Nut. (d) Do a detail inspection on and around the Ballscrew and the Ball Nut for existence of metallic particles, other solid particles, or corrosion products. (e) The Ball Nut bearings are approximately 0.218 inch in diameter.(f) Do a detailed inspection for cross-threading, distortion, stripping, metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, worn areas and differenced in thread shape (between thread grooves in the lower, middle, and upper portion of the Ballscrew). If any of the damage listed is observed, remove, inspect, and repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with 737 Umbra Cuscinetti S.p.A. CMM 27-41-01, or Linear Motion LLC CMM 27-41-01, or Skytronics Inc CMM 27-40-03.

**FIGURE 1: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND THE ATTACHMENT FITTINGS- (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION**  **1, AND GROUP 3 AIRPLANES) (SHEET 4 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 62 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 1, Configuration 2.** 

**FIGURE 2: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND THE ATTACHMENT FITTINGS - (GROUP 1, CONFIGURATION 2 AIRPLANES)**  **(SHEET 1 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 63 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT FIGURE 2: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**  **BALL NUT, AND THE ATTACHMENT FITTINGS - (GROUP 1, CONFIGURATION 2 AIRPLANES) (SHEET 2 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 64 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT FIGURE 2: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**  **BALL NUT, AND THE ATTACHMENT FITTINGS - (GROUP 1, CONFIGURATION 2 AIRPLANES) (SHEET 3 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 65 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** (a)

- Stabilizer Trim Actu- ator attachment points Inspect 1

Do a general visual inspection to see if large amount of grease exits the Ball Nut. (b) - Area Under, On, and Around Stabilizer Trim Actuator Inspect 2

(c) (d)

- Grease Inspect 3 for escaped Ball Nut bearings. (e)

- Ballscrew and Ball Nut, Trim Actuator Housing and area below Stabilizer Trim Actuator Inspect 4

from Ballscrew threads by wiping with a clean, dry, non-abrasive cloth. - Grease Remove 5

for corrosion or lifted return tubes. Ball Nut and Ball Nut Tube Retainers Inspect 6 (f)

- Ballscrew Inspect 7 to another location.

- Ballscrew Move 8 for large amount of grease that exits the Ball Nut and existence of metal particles or other debris. (b) (c) - Ballscrew and Ball Nut Inspect 9

(f)

- Ballscrew Inspect 10 (a) Do a detailed inspection of the lower and upper gimbal for cracks and other damage. Inspect the area around the bushings. Make sure that the Stabilizer Trim Actuator is correctly attached to the airplane structure. (b) Large amount of grease present around the ball-screw indicate that a faulty seal or raised Ball Nut Return Tubes may be present. (c) Metallic particles in grease may be indication of degradation of the balls in the Ball Nut. (d) Do a detail inspection of the grease on and around the Ballscrew and the Ball Nut for existence of metallic particles, other solid particles or corrosion products. (e) The Ball Nut bearings are approximately 0.218 inch in diameter. (f) Do a detailed inspection for cross-threading, distortion, stripping, metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, worn areas and differences in thread shape (between thread grooves in the lower, middle, and upper portion of the Ballscrew). If any of the damage listed isobserved, remove, inspect, and repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with 737 Umbra Cuscinetti S.p.A. CMM 27-41-01, or Linear Motion LLC CMM 27-41- 01, or Skytronics Inc CMM 27-40-03.

**FIGURE 2: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW, BALL NUT, AND THE ATTACHMENT FITTINGS - (GROUP 1, CONFIGURATION 2 AIRPLANES)**  **(SHEET 4 OF 4)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 66 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 2, Configuration 2.** 

**FIGURE 3: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**

**BALL NUT, AND, AND THE ATTACHMENT FITTINGS - (GROUP 2, CONFIGURATION 2 AIRPLANES) (SHEET 1 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 67 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT FIGURE 3: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**  **BALL NUT, AND, AND THE ATTACHMENT FITTINGS - (GROUP 2, CONFIGURATION 2 AIRPLANES) (SHEET 2 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 68 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT FIGURE 3: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**  **BALL NUT, AND, AND THE ATTACHMENT FITTINGS - (GROUP 2, CONFIGURATION 2 AIRPLANES) (SHEET 3 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 69 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** (a)

- Horizontal StabilizerTrim Actuator attachment points Inspect 1

(b) (c)

- Grease Inspect 2 for escaped Ballnut bearings. (d)

- Ballscrew and Ball Nut, Trim Actuator Housing and area below HorizontalStabilizer Trim Actuator Inspect 3

from Ballscrew threads by wiping with a clean, dry, non-abrasive cloth. - Oil and Grease Remove 4 Do a detailed inspection for deformation and corrosion or lifted return tubes. Ball Nut and Ball Nut Return Tubes Inspect 5

(e)

- Ballscrew Inspect 6 to another location.

- Ballscrew Move 7 for existence of metal particles or other debris. (b) - Ballscrew and Ball Nut Inspect 8 (e)

- Horizontal Stabilizer Ballscrew Inspect 9 (a) Do a detailed inspection of the lower and upper gimbal for cracks and other damage. Inspect the area around the bushings. Make sure that the Stabilizer Trim Actuator is correctly attached to the airplane structure. (b) Metallic particles in grease may be indication of degradation of the balls in the Ball Nut. (c) Do a detail inspection of the grease on and around the Ballscrew and the Ball Nut for existence of metallic particles, other solid particles or corrosion products. (d) The Ball Nut bearings are approximately 0.218 inch in diameter. (e) Do a detailed inspection for cross-threading, distortion, stripping, metallic particles, pitting, gouging, corrosion, spalling, brinelling, cracks, worn areas and differences in thread shape (between thread grooves in the lower, middle, and upper portion of the Ballscrew). If any of the damage listed isobserved, remove, inspect, and repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with 737 Skytronics Inc CMM 27-40-03.

**FIGURE 3: HORIZONTAL STABILIZER TRIM ACTUATOR - DETAILED INSPECTION OF THE BALLSCREW,**

**BALL NUT, AND, AND THE ATTACHMENT FITTINGS - (GROUP 2, CONFIGURATION 2 AIRPLANES) (SHEET 4 OF 4)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 70 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 1-2, Configuration 1; Group 3.** 

**FIGURE 4: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES)**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 71 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** (a) (b) 1 D00633 Grease Apply 1 if grease exits through the Upper Seal, Lower Seal, and around the Tube Retainer areas. (c) (d) (e) - - Ballscrew and Ball Nut Inspect 2

that exits the Ball Nut for signs ofmetallic particles, discolored water, rust, or other solid particles. (f) - - Grease Inspect 3

(a) in accordance with 737 Aircraft Maintenance Manual 737-100/200 AMM 12-22-41 or 737-300/400/500 AMM 12-22-41 untill clean, new, fresh grease exits through the grease vent. (b) If clean, new, fresh grease fails to exit the grease vent OR the upper seal, repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 7 .(c) Clean, new fresh grease, that exits from the upper seal is also an acceptable indication of proper lubrication of the Ball Nut. (d) Small amounts of grease may exit the lower seal and is considered acceptable as long as the general visual inspection of the area under, on, and around the stabilizer trim actuator in accordance with Paragraph 3.B., Work Instructions - Work Package 1, Step 1.e.(2) was found satisfactory. (e) Small amounts of grease may exit the ball nut through the Tube retainer areas (from the Return Tubes). If small amount of grease is observed around the Tube Retainers do a detailed inspection of the Ball Nut Tube Retainers for deformation and corrosion or lift Return Tubes. If the Ball Nut Tube Retainers have deformation or corrosion Repair/Replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 7. If no damage of the Tube Retainers is found the condition is acceptable. If large amount of grease exits through the Tube Retainer areas, the Return Tubes may be lifted and the Stabilizer Trim Actuator must be repaired or replaced (as necessary) in accordance with FIGURE 7. (f) If visible metallic particles are observed in the grease there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew actuator can happen but this will not release visible metallic particles in the grease.

**FIGURE 4: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES)**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 72 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 1, Configuration 2.** 

**FIGURE 5: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 1, CONFIGURATION 2 AIRPLANES)**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 73 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** (a) (b) 1 D00633 Grease Apply 1 if grease exits through the Upper Seal, Lower Seal and around the Tube Retainer areas. (c) (d) (e) - - Ballscrew and Ball Nut Inspect 2

that exits the Ball Nut for signs ofmetallic particles, discolored water, rust, or other solid particles. (f) - - Grease Inspect 3

(a) in accordance with 737-300/400/500 AMM 12-22-41 untill clean, new, fresh grease exits through the grease vent. (b) If clean, new, fresh grease fails to exit the grease vent OR the upper seal, repair/replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 8.(c) Clean, new, fresh grease, that exits from the upper seal is also an acceptable indication of proper lubrication of the Ball Nut. (d) Small amounts of grease may exit the lower seal and is considered acceptable as long as the general visual inspection of the area under, on, and around the stabilizer trim actuator in accordance with Paragraph 3.B., Work Instructions - Work Package 2, Step 1.e.(2) was found satisfactory. (e) Small amounts of grease may exit the ball nut through the Tube retainer areas (from the Return Tubes). If small amount of grease is observed around the Tube Retainers do a detailed inspection of the Ball Nut Tube Retainers for deformation and corrosion or lift Return Tubes. If the Ball Nut Tube Retainers have deformation or corrosion Repair/Replace (as necessary) the Stabilizer Trim Actuator in accordance with FIGURE 8 . If no damage of the Tube Retainers is found the condition is acceptable. If large amount of grease exits through the Tube Retainer areas, the Return Tubes may be lifted and the Stabilizer Trim Actuator must be repaired or replaced (as necessary) in accordance with FIGURE 8 . (f) If visible metallic particles are observed in the grease there may be some damage in the Ballscrew/Ball Nut assembly. Normal wear of the Ballscrew actuator can happen but this will not release visible metallic particles in the grease.

**FIGURE 5: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 1, CONFIGURATION 2 AIRPLANES)**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 74 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 2, Configuration 2.** 

**FIGURE 6: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 2, CONFIGURATION 2 AIRPLANES)**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 75 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** Refer to 737-100/200 AMM 12- 22-41. - D00633 Grease Apply 1

in the lubricator reservoirs in accordance with 737-100/200 AMM 27-41-121. - MIL-L-7870 Oil Fill 2

**FIGURE 6: LUBRICATION OF THE HORIZONTAL STABILIZER TRIM ACTUATOR (GROUP 2, CONFIGURATION 2 AIRPLANES)**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 76 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 1-2, Configuration 1; Group 3.** 

**FIGURE 7: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES)**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 77 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** Refer to 737-100/200 AMM 27- 41-81 or 737-300/400/500 AMM 27-41-81. 1

- Horizontal Stabilizer Trim Actuator Remove 1

Refer to Umbra Cuscinetti, S.p.A. CMM 27-41-01, or Linear Motion,LLC CMM 27-41-01, or Skytronics Inc CMM 27-40-03 and Boeing CMM 27-45-11. 1

- Horizontal Stabilizer Trim Actuator Repair/ Overhaul 2

Refer to CMM 27-41-81. (b) 1

- Horizontal Stabilizer Trim Actuator Install (a) 3 (b) 1

- Horizontal Stabilizer Trim Actuator Test 4 (a) Install a repaired or a new Horizontal Stabilizer Trim Actuator. (b) If you replace a damaged Horizontal Stabilizer Trim Actuator with a serviceable Horizontal Stabilizer Trim Actuator that is not new or not overhauled, then you must do the Detailed Inspection for the replacement Horizontal Stabilizer Trim Actuator as given in this service bulletin, and the Horizontal Stabilizer Gearbox End Play Test in accordance with OHM 27-45-11 .

**FIGURE 7: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 1 CONFIGURATION 1, GROUP 2 CONFIGURATION 1, AND GROUP 3 AIRPLANES)**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 78 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 1, Configuration 2.** 

**FIGURE 8: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 1, CONFIGURATION 2 AIRPLANES)**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 79 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** Refer to 737-300/400/500 AMM 27-41-81. 1

- Horizontal Stabilizer Trim Actuator Remove 1 Refer to Umbra Cuscinetti, S.p.A. CMM 27-41-01, or Linear Motion,LLC CMM 27-41-01, or Skytronics Inc CMM 27-40-03 and Boeing CMM 27-45-11. 1

- Horizontal Stabilizer Trim Actuator Repair/Overhaul 2

Refer to 737-300/400/500 AMM 27-41-81. (b) 1

- Horizontal Stabilizer Trim Actuator Install (a) 3 (b) 1

- Horizontal Stabilizer Trim Actuator Test 4 (a) Install a repaired or a new Horizontal Stabilizer Trim Actuator. (b) If you replace a damaged Horizontal Stabilizer Trim Actuator with a serviceable Horizontal Stabilizer Trim Actuator that is not new or not overhauled, then you must do the Detailed Inspection for the replacement Horizontal Stabilizer Trim Actuator as given in this service bulletin, and the Horizontal Stabilizer Gearbox End Play Test in accordance with OHM 27-45-11 .

**FIGURE 8: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 1, CONFIGURATION 2 AIRPLANES)**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 80 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT This Figure applies only to: Group 2, Configuration 2.** 

**FIGURE 9: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 2, CONFIGURATION 2 AIRPLANES)**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 81 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT NOTES**  **QTY PART NUMBER**  **NAME TASK**  **STEP** Refer to 737-100/200 AMM 27- 41-81. 1

- Horizontal Stabilizer Trim Actuator Remove 1 Refer to Skytronics Inc CMM 27- 40-03 and Boeing CMM 27-45- 11. 1

- Horizontal Stabilizer Trim Actuator Repair/Overhaul 2

Refer to 737-100/200 AMM 27- 41-81. (b) 1

- Horizontal Stabilizer Trim Actuator Install (a) 3 (b) 1

- Horizontal Stabilizer Trim Actuator Test 4 (a) Install a repaired or a new Horizontal Stabilizer Trim Actuator. (b) If you replace a damaged Horizontal Stabilizer Trim Actuator with a serviceable Horizontal Stabilizer Trim Actuator that is not new or not overhauled, then you must do the Detailed Inspection for the replacement Horizontal Stabilizer Trim Actuator as given in this service bulletin, and the Horizontal Stabilizer Gearbox End Play Test in accordance with OHM 27-45-11 .

**FIGURE 9: HORIZONTAL STABILIZER TRIM ACTUATOR BALLSCREW AND BALL NUT - REPAIR/REPLACE - (GROUP 2, CONFIGURATION 2 AIRPLANES)**  **(SHEET 2 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 82 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**Use this Inspection Report form to provide data to Boeing for the Horizontal Stabilizer Trim Actuator that is inspected at specified intervals as given in this service bulletin: Operator: _____________________________________ Today's Date: _________________________ Prepared by: ___________________________________ Title: _________________________________ Telephone Number: _____________________________ Base: _______________________________ Horizontal Stabilizer Trim Actuator part number and dash number: _______________________________ Stabilizer Trim Actuator Serial Number: ___________________________________ Date of inspection: ________________________ Airplane Variable Number/ Line Number: __________________________ Total number of Flight Cycles and Flight Hours on the airplane at the inspection date: ____________________ cycles ______________________hours Metallic debris found in grease: YES ____ NO ____ Ball Nut bearings found in vicinity of the Ball Nut, Gear Box, or below the Horizontal Stabilizer Trim Actuator: YES ____ NO ____ Ballscrew with threads damage: YES ____ NO ____ Horizontal Stabilizer Trim Actuator attachment points with cracks or other damage: YES ____ NO ____ Upper and lower Gimbal with damage: YES ____ NO ____
Please provide a brief description of the damage, a sketch or a picture. When a portion of the Detailed Inspection failed, give the completed inspection Report form and attachments, sketches, or pictures to your Boeing Field Service Representative or send the Inspection Report directly to this address: Manager, Service Bulletin Engineering Boeing Commercial Airplane Group P.O. Box 3707, mail Code 2H-36 Seattle, WA 98124-2207

**Appendix A: INSPECTION REPORT FORM FOR SB 737-27A1278 (SHEET 1 OF 1)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: May 24, 2007 737-27A1278 Revision 1 January 07, 2010 83 of 83 **BOEING SERVICE BULLETIN 737-27A1278 ALERT**  **ALERT**