### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-27A1297**  Original Issue: April 16, 2010 ATA System: 2731 **SUBJECT:** FLIGHT CONTROLS - Elevator Tab Control Mechanism Detailed Inspection Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 1 of 57 2.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 2 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 F. Approval. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 19 K. Publications Affected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. Industry Support Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1. Kits/Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 21 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4. Parts Removed and Not Replaced. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 22 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 FIGURE 1: ACCESS PANEL REMOVAL & INSTALLATION - LEFT SIDE. . . . . . . . . . . . . . . . 32 FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE. . . . . . . 34 FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE. . . . . . 39 FIGURE 4: ACCESS PANEL REMOVAL & INSTALLATION - RIGHT SIDE. . . . . . . . . . . . . . . 44 FIGURE 5: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE. . . . . . 46 FIGURE 6: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE. . . . . 51 FIGURE 7: DETERMINING IF REPLACEMENT MECHANISM IS NOT BOEING BUILT. . . . . . . . 56

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 3 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 4 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Summary**  **Number: 737-27A1297** Original Issue: April 16, 2010 ATA System: 2731 **SUBJECT:** FLIGHT CONTROLS - Elevator Tab Control Mechanism Detailed Inspection 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** An operator experienced a vibration event 21 days after performing inspections on the swage ring and spacer on the elevator tab control mechanism (mechanism) in accordance with Service Bulletin (SB) 737-27A1296. Investigation revealed that the vibration was most likely caused by the same conditions that Service Bulletin 737-27A1296 was meant to detect, but did not. For the most critical group of airplanes, this service bulletin does a more enhanced inspection than the inspection in SB 737-27A1296 and continues with repeat inspections until the elevator tab control mechanism is replaced. The more enhanced inspection includes using a feeler gage at specific locations to check for gaps. The inspections in this SB will detect a loose bearing in the aft attach lugs (lugs) of the elevator tab control mechanism. A loose bearing in the aft attach lug of the elevator tab control mechanism could lead to unwanted elevator tab freeplay and then elevator tab vibration which could lead to structural failure of the elevator or the horizontal stabilizer. **ACTION** Remove the seal plate and lower hinge cover to gain access to the elevator tab control mechanism and do a detailed inspection of the aft attach lugs (lugs). Look for any gaps and look for rotation of the spacer. Also, use a feeler gage to look for any gaps at certain locations. If there is a gap or a loose spacer, then replace the elevator control tab mechanism per the AMM and this SB. If there is no gap or a loose spacer, then return the airplane to a serviceable condition. For Group 1 airplanes, do repeat inspections in accordance with this SB at the times specified in paragraph 1.E., Compliance. Do the repeat inspections until the elevator tab control mechanism (mechanism) is replaced in accordance with this SB within the compliance time specified in paragraph 1.E, Compliance. Group 2 airplanes do not have to do repeat inspections unless they have a discrepant mechanism and they replace it with a non-Boeing built mechanism. **EFFECTIVITY** 737-700, -700C, -800, and -900ER Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 5 of 57**COMPLIANCE** Refer to Paragraph 1.E., Compliance. The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. **INDUSTRY SUPPORT INFORMATION** At the time of release of this service bulletin, warranty remedies have not been determined. A subsequent revision or Information Notice will address the warranty remedies available, if any. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 6 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 7 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 8 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**

BLANK PAGE

### Commercial **Airplanes** 

# 737 Service Bulletin **ALERT Number: 737-27A1297**  Original Issue: April 16, 2010 ATA System: 2731 **SUBJECT:** FLIGHT CONTROLS - Elevator Tab Control Mechanism Detailed Inspection THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes

**DESCRIPTION CONFIGURATION**  **GROUP** Airplanes Line number 2508 to 2707

- 1 Airplanes Line Number 2708 to 3250

- 2 That have ETOPS operational approval 1 That do not have ETOPS operational approval 2

Airplane Models: 737-700, 737-700C, 737-800, 737-900ER **Group Variable Number**  2 YB633 - YB635 1 YB974 1 YB986 - YB987 2 YB988 - YB995 2 YC095 1 YD415

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 9 of 57**Group Variable Number**  2 YD416 1 YF001 2 YF002 - YF006 1 YF021 - YF026 2 YF027 - YF039 2 YF046 1 YF051 - YF052 2 YF053 - YF060 1 YF086 2 YF112 - YF114 2 YF116 - YF117 2 YF121 - YF123 1 YF176 - YF178 2 YF191 - YF192 2 YF201 - YF244 2 YF401 - YF402 2 YF451 - YF455 2 YF501 - YF576 2 YF701 - YF705 2 YF801 - YF802 2 YF831 - YF832 2 YF901 - YF903 2 YF921 1 YG120 2 YG121 - YG125 2 YG221 - YG223 1 YG711 1 YH011 - YH012 2 YH031 - YH048 1 YH053 - YH054 2 YH055 1 YH103 - YH115 2 YH116 - YH130

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 10 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Group**  **Variable Number** 1 YH201 - YH202 1 YH206 - YH207 1 YH301 2 YH302 - YH305 2 YH321 - YH322 1 YJ009 - YJ010 1 YJ560 - YJ566 2 YJ567 - YJ576 1 YJ597 2 YJ598 - YJ599 1 YJ874 - YJ875 2 YJ876 - YJ880 1 YJ904 1 YJ908 2 YJ909 - YJ910 1 YK133 1 YK167 1 YK176 2 YK177 2 YK186 2 YK191 2 YK196 2 YK201 - YK202 1 YK309 2 YK310 - YK313 1 YK337 - YK338 2 YK339 - YK340 1 YK373 - YK375 2 YK376 - YK378 2 YK461 - YK465 2 YK471 2 YK486 - YK487 1 YK495

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 11 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Group**  **Variable Number** 2 YK496 - YK497 1 YK521 - YK523 2 YK524 - YK529 1 YK566 - YK569 2 YK570 1 YK615 - YK616 1 YK626 - YK627 2 YK628 - YK630 1 YK661 2 YK662 - YK665 1 YK671 2 YK672 2 YK676 - YK677 2 YK681 - YK686 2 YK691 1 YK710 - YK712 2 YK713 1 YK757 - YK760 2 YK761 - YK770 2 YK776 - YK778 1 YK871 - YK887 2 YK888 - YK899 1 YK911 2 YK912 2 YK919 1 YK924 - YK927 1 YK951 - YK952 2 YK953 - YK956 2 YK972 - YK980 1 YK985 2 YK986 - YK992 1 YL110 - YL116 2 YL117 - YL131

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 12 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Group**  **Variable Number** 1 YL206 - YL209 2 YL210 - YL218 2 YL283 - YL284 1 YL316 - YL319 2 YL320 - YL321 2 YL351 - YL353 1 YL371 - YL373 2 YL374 2 YL401 1 YL426 2 YL427 - YL429 2 YL438 - YL444 1 YL472 - YL473 2 YL474 - YL478 1 YL504 - YL505 2 YL506 - YL509 1 YL532 - YL533 2 YL534 2 YL541 - YL544 1 YL562 - YL565 2 YL566 - YL568 1 YL591 - YL592 2 YL593 1 YL605 - YL606 1 YL611 2 YL612 1 YL616 2 YL617 1 YL621 2 YL626 2 YL631 - YL633 1 YL661 - YL664 2 YL676 - YL681

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 13 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Group**  **Variable Number** 2 YL691 2 YL701 - YL703 2 YL731 2 YL751 - YL752 2 YL761 - YL771 2 YL801 - YL809 1 YL904 - YL907 2 YL908 - YL910 2 YL921 - YL930 2 YL933 - YL936 1 YL951 - YL952 2 YL953 - YL962 1 YM232 - YM238 2 YM239 - YM242 1 YM354 - YM374 2 YM375 - YM390 2 YM594 - YM599 1 YM647 - YM651 2 YM652 2 YM673 - YM674 1 YM691 - YM692 2 YM693 - YM696 1 YM701 - YM702 2 YM703 - YM710 2 YM761 - YM762 1 YN015 - YN016 1 YN024 2 YN080 - YN082 2 YN202 1 YN215 - YN216 2 YN217 - YN219 1 YN232 2 YN233 - YN235

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 14 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Group**  **Variable Number** 2 YN261 2 YQ001 - YQ003 2 YQ011 2. Spares Affected Examine your spares supply for the parts or components identified in Paragraph 2.C., Parts Necessary for Each Airplane. If any parts or components are found, refer to Paragraph 2.C. for the recommended use. **B. Concurrent Requirements** None. **C. Reason** An operator experienced a vibration event 21 days after performing inspections on the swage ring and spacer on the elevator tab control mechanism (mechanism) in accordance with Service Bulletin (SB) 737-27A1296. Investigation revealed that the vibration was most likely caused by the same conditions that Service Bulletin 737-27A1296 was meant to detect, but did not. For the most critical group of airplanes, this service bulletin does a more enhanced inspection than the inspection in SB 737-27A1296 and continues with repeat inspections until the elevator tab control mechanism is replaced. The more enhanced inspection includes using a feeler gage at specific locations to check for gaps. The inspections in this SB will detect a loose bearing in the aft attach lugs (lugs) of the elevator tab control mechanism. A loose bearing in the aft attach lug of the elevator tab control mechanism could lead to unwanted elevator tab freeplay and then elevator tab vibration which could lead to structural failure of the elevator or the horizontal stabilizer. **D. Description** Remove the seal plate and lower hinge cover to gain access to the elevator tab control mechanism (mechanism) and do a detailed inspection of the aft attach lugs (lugs). Look for any gaps and look for rotation of the spacer. Also, use a feeler gage to look for any gaps at certain locations. If there is a gap or a loose spacer, then replace the elevator control tab mechanism per the AMM and this SB. If there is no gap or a loose spacer, then return the airplane to a serviceable condition. For Group 1 airplanes, do repeat inspections in accordance with this SB at the times specified in paragraph 1.E., Compliance. Do the repeat inspections until the elevator tab control mechanism is replaced in accordance with this SB within the compliance time specified in paragraph 1.E, Compliance. Group 2 airplanes do not have to do repeat inspections unless they have a discrepant mechanism and they replace it with a non-Boeing built mechanism. The work in this service bulletin is done in the maintenance zone(s) given below.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 15 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Group 1:** 
**Affected Maintenance Zones Zone**  **Model** 333, 334, 343, 344 737-700, 737-700C, 737-800, 737-900ER **Group 2:**
**Affected Maintenance Zones Zone**  **Model** 333, 334, 343, 344 737-700, 737-800, 737-900ER **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. **Table 1: ELEVATOR TAB CONTROL MECHANISM INSPECTION - LEFT SIDE Repeat Interval**  **(Not to Exceed) Compliance Time**  **Action Condition**  300 flight hours (a) (b)Within 12 days after the date of the original issue of this service bulletin except beginning 7 days after the date of the original issueof the service bulletin, no airplane may operate anETOPS flight unless it has been inspected Do a detailed inspection of the elevator tab control mechanism (mechanism) in accordance with Step 2 of paragraph 3.B., Work Instructions. Group 1 airplanes.

(c) Within 30 days af- ter the date of the original issue of this service bulletin Do a detailed inspection of the elevator tab controlmechanism in accordance with Step 2 ofparagraph 3.B., Work Instructions Group 2, Configuration 1

- - No action required Group 2, Configuration 2

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 16 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Table 1: ELEVATOR TAB CONTROL MECHANISM INSPECTION - LEFT SIDE**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Before further flight (a) (b) Replace the elevator tab control mechanism and do detailed inspection before and after installing it, in accordance with Step 7 of paragraph 3.B., Work Instructions All airplanes:Elevator tab control mechanism is found to be discrepant OR Replacement elevator tab control mechanism is found to be discrepant. 300 flight hours (a) (b) Within 300 flighthours after installation of the nonBoeing built replacement mechanism Do a detailed inspection of the elevator tab controlmechanism in accordance with Step 2 ofparagraph 3.B., Work Instructions. Group 2, Configuration 1 airplanes that installed anon-Boeing built replacement mechanism

(a) Installing a Boeing built replacement mechanism in accordance with Step 7 of paragraph 3.B., Work Instructions of this SB terminates the repeat detailed inspections of the elevator tab control mechanism in accordance with this SB.(b) Installing a non-Boeing built replacement mechanism in accordance with Step 7 of paragraph 3.B., Work Instructions of this SB does not terminate the repeat detailed inspection of the elevator tab control mechanism in accordance with this SB. (c) If the mechanism is found to be discrepant and is replaced with a Boeing built mechanism, then no repeat inspections are required. If the mechanism is found to be discrepant and is replaced with a non-Boeing built mechanism, then repeat inspections are required in accordance with this SB.
**Table 2: ELEVATOR TAB CONTROL MECHANISM INSPECTION - RIGHT SIDE Repeat Interval**  **(Not to Exceed) Compliance Time**  **Action Condition**  300 flight hours (a) (b)Within 12 days after the date of the original issue of this service bulletin except beginning 7 days after the date of the original issueof the service bulletin, no airplane may operate anETOPS flight unless it has been inspected Do a detailed inspection of the elevator tab control mechanism (mechanism) in accordance with Step 5 of paragraph 3.B., Work Instructions. Group 1 airplanes.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 17 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT Table 2: ELEVATOR TAB CONTROL MECHANISM INSPECTION - RIGHT SIDE**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition** (c) Within 30 days af- ter the date of the original issue of this service bulletin Do a detailed inspection of the elevator tab controlmechanism in accordance with Step 5 ofparagraph 3.B., Work Instructions Group 2, Configuration 1

- - No action required Group 2, Configuration 2

- Before further flight (a) (b) Replace the elevator tab control mechanism and do detailed inspection before and after installing it, in accordance with Step 8 of paragraph 3.B., Work Instructions All airplanes:Elevator tab control mechanism is found to be discrepant OR Replacement elevator tab control mechanism is found to be discrepant. 300 flight hours (a) (b) Within 300 flighthours after installation of the nonBoeing built replacement mechanism Do a detailed inspection of the elevator tab controlmechanism in accordance with Step 5 ofparagraph 3.B., Work Instructions. Group 2, Configuration 1 airplanes that installed anon-Boeing built replacement mechanism

(a) Installing a Boeing built replacement mechanism in accordance with Step 8 of paragraph 3.B., Work Instructions of this SB terminates the repeat detailed inspections of the elevator tab control mechanism in accordance with this SB.(b) Installing a non-Boeing built replacement mechanism in accordance with Step 8 of paragraph 3.B., Work Instructions of this SB does not terminate the repeat detailed inspection of the elevator tab control mechanism in accordance with this SB. (c) If the mechanism is found to be discrepant and is replaced with a Boeing built mechanism, then no repeat inspections are required. If the mechanism is found to be discrepant and is replaced with a non-Boeing built mechanism, then repeat inspections are required in accordance with this SB. **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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 18 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT G. Manpower**  At the time of release of this service bulletin, manpower estimates have not been determined. A subsequent revision or Information Notice will add manpower estimates. **H. Weight and Balance Changes** None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data 737-600/700/800/900 Airplane Maintenance Manual (AMM) 27-31-00, 27-31-34. Boeing Standard Overhaul Practices Manual (BSOPM) 20-50-10. Boeing Service Bulletin (SB) 737-27A1296. 2. Data supplied with this Service Bulletin None. 3. Installation Drawings Used in the Preparation of this Service Bulletin None. **K. Publications Affected** 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin does not affect FCS, therefore DTIs are not necessary. **L. Interchangeability and Intermixability of Parts** Refer to Paragraph 2.C., Parts Necessary for Each Airplane, for interchangeability and intermixability information.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 19 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 20 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  None. **B. Industry Support Information** At the time of release of this service bulletin, warranty remedies have not been determined. A subsequent revision or Information Notice will address the warranty remedies available, if any. **C. Parts Necessary For Each Airplane** 1. Kits/Parts None. 2. Parts and Materials Supplied by the Operator
**Notes Existing Part Number**  **Name QTY**  **Part Number / Specification**  Do the inspection for replacedparts in accordance withthe appropriate step in paragraph 3.B., Work Instructions (a) 251A2430-15 or -17 not built by Boeing Elevator Tab Control Mechanism - Left 1 251A2430-15 or - 17 built by Boeing

Do the inspection for replacedparts in accordance withthe appropriate step in paragraph 3.B., Work Instructions (a) 251A2430-16 or -18 not built by Boeing Elevator Tab Control Mechanism - Right 1 251A2430-16 or - 18 built by Boeing

(a) You cannot use the existing part to replace the new part. After you install the new part, mark the new Boeing built mechanism with the SB number in a location that is visible when the lower hinge cover is removed.
3. Parts Modified and Reidentified None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 21 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**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: April 16, 2010 737-27A1297 22 of 57 **BOEING SERVICE BULLETIN 737-27A1297 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. The instructions identified in Paragraph 3.B., Work Instructions, and the Figure(s) give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. Use the approved fastener and process material substitutions in accordance with 737 SRM 51. Alternate fasteners are listed in 737 SRM 51 and Boeing Drawing 65-88700. 5. Refer to the SWPM 20-10-11 and SWPM 20-10-12 for the wire installation procedures, and SWPM 20-10-19 for the wire separation requirements, as accepted procedures. 6. If the length of any fastener specified in this service bulletin does not meet the installation standards in 737 SRM 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards in 737 SRM 51 may be used. 7. 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 access procedures may be required. 8. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or drop-light and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked. 9. 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.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 23 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT B. WORK INSTRUCTIONS**  1. OPEN ACCESS - LEFT SIDE: a. Remove pressure from the elevator hydraulic systems A and B. Refer to 737-600/700/800/900 AMM 27-31-00 as an accepted procedure. b. Gain access by removing the seal plate and hinge lower cover in accordance with Figure 1. c. Put the horizontal stabilizer in a neutral position: (1) Supply electrical power. Refer to 737-600/700/800/900 AMM 24-22-00 as an accepted procedure. (2) Make sure that these circuit breakers are closed: **F/O Electrical System Panel, P6-2**
**Name Number**  **Col Row**  FLIGHT CONTROL STAB TRIM CONT C00207 10 B FLIGHT CONTROL STAB TRIM ACTUATOR C00840 10 D (3) Make sure that the main cutout switch, S272 is in the NORMAL position. (4) Make sure that the STAB TRIM switch on the stab trim and cabin door panel, P8-47 is in the NORMAL position. (5) Make sure that the flaps are in the full up position. (6) Move the stabilizer to 4 units +/- .5 d. Put the elevator into a neutral position: (1) Using hand pressure, move the elevator until it is within 2 inches of the index mark mounted on the side of the tailcone. 2. DETAILED INSPECTION - LEFT SIDE: a. For the inboard aft attach lug of the elevator tab control mechanism (mechanism), look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 2 and determine if the elevator tab control mechanism is discrepant. While doing the inspection, apply inboard and outboard hand pressure to the elevator tab control mechanism in accordance with Figure 2. For the outboard aft attach lug of the elevator tab control mechanism, look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 3 and determine if the elevator tab control mechanism is discrepant. While doing the inspection, apply inboard and outboard hand pressure to the elevator tab control mechanism in accordance with Figure 3.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 24 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**(1) Spacer: If the spacer moves or rotates, then the mechanism is discrepant (2) Swage Ring to Lug interface: Make sure that there is no gap between the swage ring and the outer face of the aft attach lug such that a 0.005 inch feeler gage can be inserted more than 0.025 inch. If there is such a gap, then then the elevator tab control mechanism is discrepant. (3) Lug to Lug interface: Make sure that there is no gap between the two nested lugs such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the elevator tab control mechanism is discrepant. (4) Lug to Spacer interface: Make sure that there is no gap between the inner face of the aft attach lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the elevator tab control mechanism is discrepant. b. If the elevator tab control mechanism is discrepant, then replace it in accordance with Step 3.B.7. 3. CLOSE ACCESS - LEFT SIDE: a. Reinstall the hinge lower cover and the seal plate in accordance with Figure 1. b. Restore pressure to the elevator hydraulic systems A and B. Refer to 737-600/700/800/900 AMM 27-31-00 as an accepted procedure. If continuing with inspection of the right side, this step can be skipped. 4. OPEN ACCESS - RIGHT SIDE a. If not already done, remove pressure from the elevator hydraulic systems A and B. Refer to 737-600/700/800/900 AMM 27-31-00 as an accepted procedure. b. Gain access by removing the seal plate and hinge lower cover in accordance with Figure 4. c. If not already done, put the horizontal stabilizer in a neutral position: (1) Supply electrical power. Refer to 737-600/700/800/900 AMM 24-22-00 as an accepted procedure. (2) Make sure that these circuit breakers are closed: **F/O Electrical System Panel, P6-2**
**Name Number**  **Col Row**  FLIGHT CONTROL STAB TRIM CONT C00207 10 B FLIGHT CONTROL STAB TRIM ACTUATOR C00840 10 D (3) Make sure that the main cutout switch, S272 is in the NORMAL position.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 25 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**(4) Make sure that the STAB TRIM switch on the stab trim and cabin door panel, P8-47 is in the NORMAL position. (5) Make sure that the flaps are in the full up position. (6) Move the stabilizer to 4 units +/- 0 .5 d. If not already done, put the elevator in a neutral position: (1) Using hand pressure, move the elevator until it is within 2 inches of the index mark mounted on the side of the tailcone. 5. DETAILED INSPECTION - RIGHT SIDE: a. For the inboard aft attach lug of the elevator tab control mechanism (mechanism), look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 5 and determine if the elevator tab control mechanism is discrepant. While doing the inspection, apply inboard and outboard hand pressure to the elevator tab control mechanism in accordance with Figure 5. For the outboard aft attach lug of the elevator tab control mechanism, look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 6 and determine if the elevator tab control mechanism is discrepant. While doing the inspection, apply inboard and outboard hand pressure to the elevator tab control mechanism in accordance with Figure 6. (1) Spacer: If the spacer moves or rotates, then the mechanism is discrepant (2) Swage Ring to Lug interface: Make sure that there is no gap between the swage ring and the outer face of the aft attach lug such that a 0.005 inch feeler gage can be inserted more than 0.025 inch. If there is such a gap, then then the elevator tab control mechanism is discrepant. (3) Lug to Lug interface: Make sure that there is no gap between the two nested lugs such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the elevator tab control mechanism is discrepant. (4) Lug to Spacer interface: Make sure that there is no gap between the inner face of the aft attach lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the elevator tab control mechanism is discrepant. b. If the elevator tab control mechanism is discrepant, then replace it in accordance with Step 3.B.8. 6. CLOSE ACCESS - RIGHT SIDE a. Reinstall the hinge lower cover and the seal plate in accordance with Figure 4. b. Restore pressure to the elevator hydraulic systems A and B. Refer to 737-600/700/800/900 AMM 27-31-00 as an accepted procedure. 7. REPLACEMENT OF A MECHANISM- LEFT SIDE

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 26 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT WARNING:**  WHEN INSTALLING THE PINS TO CONNECT THE ELEVATOR TAB CONTROL MECHANISM TO THE ELEVATOR, MAKE SURE YOU DON'T DAMAGE THE LUGS OR THE BEARINGS. IF A LUG OR BEARING IS DAMAGED, THEN IT COULD LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN ELEVATOR TAB VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER. a. Gain access as required and remove the elevator tab control mechanism (mechanism). Refer to 737-600/700/800/900 AMM 27-31-34 as an accepted procedure. b. Replace the elevator tab control mechanism as follows: (1) Before you install the replacement mechanism, do the following inspections: (a) Do a general visual inspection of the replacement mechanism in accordance with Figure 7 to determine if it is a Boeing built mechanism or a non-Boeing built mechanism. 1) If part number 251A2430-15, 251A2430-16, 251A2430-17, or 251A2430 -18 appears in the area shown in Figure 7, and if there is a manufacturers number (MFR number) of 468280 within 0.5 inches of the part number, then the replacement mechanism is not Boeing built. 2) If either of the two following conditions is true, then the replacement mechanism is Boeing built: a) part number 251A2430-15, 251A2430-16, 251A2430-17, or 251A2430 -18 does not appear in the area shown in Figure 7. b) part number 251A2430-15, 251A2430-16, 251A2430-17, or 251A2430 -18 appears in the area shown in Figure 7, but there is not a manufacturers number (MFR number) of 468280 within 0.5 inches of the part number. 3) You can install either a Boeing built mechanism or a non Boeing built mechanism. Refer to paragraph 1.E., Compliance, for compliance information related to installing a non Boeing built mechanism. (b) For the inboard attach lug of the elevator tab control mechanism, look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 2, except as noted below, and determine if the replacement mechanism is discrepant. For the outboard attach lug of the elevator tab control mechanism, look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 3, except as noted below, and determine if the replacement mechanism is discrepant. **NOTE:** The figures in this service bulletin show the detailed inspection being done on an elevator tab control mechanism that is installed. If a replacement mechanism is being inspected before it is installed, then:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 27 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**– Do not apply force as shown in the figures, – These figures will not show what the mechanic will see when doing the inspection, but this is OK. 1) Spacer: If the spacer moves or rotates, then the replacement mechanism is discrepant 2) Swage Ring to Lug interface: Make sure that there is no gap between the swage ring and the outer face of the aft attach lug such that a 0.005 inch feeler gage can be inserted more than 0.025 inch. If there is such a gap, then then the replacement mechanism is discrepant. 3) Lug to Lug interface: Make sure that there is no gap between the two nested lugs such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the replacement mechanism is discrepant. 4) Lug to Spacer interface: Make sure that there is no gap between the inner face of the aft attach lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the replacement mechanism is discrepant. (c) If the replacement mechanism is discrepant, then it cannot be installed. (2) Install the replacement mechanism. Refer to 737-600/700/800/900 AMM 27-31-34 as an accepted procedure. (3) After you install the replacement mechanism, do a detailed inspection of the elevator tab control mechanism in accordance with Step 3.B.2. (4) If the replacement mechanism is a Boeing built mechanism, then mark it with the SB number. Put the mark in a location that is visible with the lower hinge cover removed. Refer to BSOPM 20-50-10 as an accepted procedure for marking the mechanism. c. Close access as required. Refer to 737-600/700/800/900 AMM 27-31-34 as an accepted procedure. d. Functional tests and a manual reversion flight test of the airplane are required when an elevator tab control mechanism is replaced. Refer to 737-600/700/800/900 AMM 27-31-00 and 27-31-34 as an accepted procedure. 8. REPLACEMENT OF A MECHANISM - RIGHT SIDE **WARNING:** WHEN INSTALLING THE PINS TO CONNECT THE ELEVATOR TAB CONTROL MECHANISM TO THE ELEVATOR, MAKE SURE YOU DON'T DAMAGE THE LUGS OR THE BEARINGS. IF A LUG OR BEARING IS DAMAGED, THEN IT COULD LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN ELEVATOR TAB VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER. a. Gain access as required and remove the elevator tab control mechanism (mechanism). Refer to 737-600/700/800/900 AMM 27-31-34 as an accepted procedure. b. Replace the elevator tab control mechanism as follows:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 28 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**(1) Before you install the replacement mechanism, do the following inspections: (a) Do a general visual inspection of the replacement mechanism in accordance with Figure 7 to determine if it is a Boeing built mechanism or a non-Boeing built mechanism. 1) If part number 251A2430-15, 251A2430-16, 251A2430-17, or 251A2430 -18 appears in the area shown in Figure 7, and if there is a manufacturers number (MFR number) of 468280 within 0.5 inches of the part number, then the replacement mechanism is not Boeing built. 2) If either of the two following conditions is true, then the replacement mechanism is Boeing built: a) part number 251A2430-15, 251A2430-16, 251A2430-17, or 251A2430 -18 does not appear in the area shown in Figure 7. b) part number 251A2430-15, 251A2430-16, 251A2430-17, or 251A2430 -18 appears in the area shown in Figure 7, but there is not a manufacturers number (MFR number) of 468280 within 0.5 inches of the part number. 3) You can install either a Boeing built mechanism or a non Boeing built mechanism. Refer to paragraph 1.E., Compliance, for compliance information related to installing a non Boeing built mechanism. (b) For the inboard attach lug of the elevator tab control mechanism, look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 5, except as noted below, and determine if the replacement mechanism is discrepant. For the outboard attach lug of the elevator tab control mechanism, look for gaps and use a feeler gage and finger pressure to do a detailed inspection in accordance with Figure 6, except as noted below, and determine if the replacement mechanism is discrepant. **NOTE:** The figures in this service bulletin show the detailed inspection being done on an elevator tab control mechanism that is installed. If a replacement mechanism is being inspected before it is installed, then:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 29 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**– Do not apply force as shown in the figures, – These figures will not show what the mechanic will see when doing the inspection, but this is OK. 1) Spacer: If the spacer moves or rotates, then the replacement mechanism is discrepant 2) Swage Ring to Lug interface: Make sure that there is no gap between the swage ring and the outer face of the aft attach lug such that a 0.005 inch feeler gage can be inserted more than 0.025 inch. If there is such a gap, then then the replacement mechanism is discrepant. 3) Lug to Lug interface: Make sure that there is no gap between the two nested lugs such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the replacement mechanism is discrepant. 4) Lug to Spacer interface: Make sure that there is no gap between the inner face of the aft attach lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. If there is such a gap, then the replacement mechanism is discrepant. (c) If the replacement mechanism is discrepant, then it cannot be installed. (2) Install the replacement mechanism. Refer to 737-600/700/800/900 AMM 27-31-34 as an accepted procedure. (3) After you install the replacement mechanism, do a detailed inspection of the elevator tab control mechanism in accordance with Step 3.B.5. (4) If the replacement mechanism is a Boeing built mechanism, then mark it with the SB number. Put the mark in a location that is visible with the lower hinge cover removed. Refer to BSOPM 20-50-10 as an accepted procedure for marking the mechanism. c. Close access as required. Refer to 737-600/700/800/900 AMM 27-31-34 as an accepted procedure. d. Functional tests and a manual reversion flight test of the airplane are required when an elevator tab control mechanism is replaced. Refer to 737-600/700/800/900 AMM 27-31-00 and 27-31-34 as an accepted procedure. 9. Report all initial inspection findings to Boeing and report all discrepant mechanism findings from a repeat inspection to Boeing. Identify the airplane and give the total flight hours and flight cycles of the airplane. If there is damage, give the extent of the damage. Send your report to: BOEING COMMERCIAL AIRPLANES GROUP ATTENTION: MANAGER, AIRLINE SUPPORT Email: rse.boecom@boeing.com 10. Send all removed elevator tab control mechanisms to: Spares Distribution Center

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 30 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**Repair Overhaul and Exchange Services, SSA 111 Boeing Commercial Airplane Group 2201 South 142nd, Door W10 Seatac, Washington USA 98168

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 31 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 1: ACCESS PANEL REMOVAL & INSTALLATION - LEFT SIDE**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 32 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  1
- seal plate Remove / Keep 1 1
- elevator hinge lower cover Remove / Keep 2

1
- elevator hinge lower cover Install (Kept) 3

1
- seal plate Install (Kept) 4

**FIGURE 1: ACCESS PANEL REMOVAL & INSTALLATION - LEFT SIDE (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 33 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE**  **(SHEET 1 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 34 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE**  **(SHEET 2 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 35 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE**  **(SHEET 3 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 36 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  **CAUTION:** DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.Using hand pressure, apply force tothe mechanism alternating between theinboard and outboard direction whiledoing the inspections in the following steps. The force canbe applied at any location on the mechanism, but no morethan four inches forward of the elevator front spar. - - force Apply 1

Detailed. Look for gaps. 1
- swage ring/lug interface Inspect 2
Detailed. Look for gaps. 1
- lug/lug interface Inspect
Detailed. Look for gaps. 1
- lug/spacer interface Inspect (b) 1
- spacer Inspect 3 (a) If there is sealant in the interface, do not remove it. 1
- swage ring/lug interface Inspect 4

(c) If there is sealant in the interface, do not remove it. 1
- lug/lug interface Inspect 5

(c) If there is sealant in the interface, do not remove it. 1
- lug/spacer interface Inspect 6

(a) Using a feeler gage, make sure that there is no gap between the swage ring and the outer face of the lugsuch that a 0.005 inch feeler gage can be inserted more than 0.025 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE (SHEET 4 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 37 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (b) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger pressure and try to rotate the spacer. (c) Using a feeler gage, Make sure that there is no gap between the two nested lugs or between the inner face of the lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 2: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - LEFT SIDE (SHEET 5 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 38 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE**  **(SHEET 1 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 39 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE**  **(SHEET 2 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 40 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE**  **(SHEET 3 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 41 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  **CAUTION:** DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.Using hand pressure, apply force tothe mechanism alternating between theinboard and outboard direction whiledoing the inspections in the following steps. The force canbe applied at any location on the mechanism, but no morethan four inches forward of the elevator front spar. - - force Apply 1

Detailed. Look for gaps. 1
- swage ring/lug interface Inspect 2
Detailed. Look for gaps. 1
- lug/lug interface Inspect
Detailed. Look for gaps. 1
- lug/spacer interface Inspect (b) 1
- spacer Inspect 3 (a) If there is sealant in the interface, do not remove it. 1
- swage ring/lug interface Inspect 4

(c) If there is sealant in the interface, do not remove it. 1
- lug/lug interface Inspect 5

(c) If there is sealant in the interface, do not remove it. 1
- lug/spacer interface Inspect 6

(a) Using a feeler gage, make sure that there is no gap between the swage ring and the outer face of the lugsuch that a 0.005 inch feeler gage can be inserted more than 0.025 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE (SHEET 4 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 42 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (b) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger pressure and try to rotate the spacer. (c) Using a feeler gage, Make sure that there is no gap between the two nested lugs or between the inner face of the lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 3: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - LEFT SIDE (SHEET 5 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 43 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 4: ACCESS PANEL REMOVAL & INSTALLATION - RIGHT SIDE**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 44 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for one side of the airplane.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  1
- seal plate Remove / Keep 1 1
- elevator hinge lower cover Remove / Keep 2

1
- elevator hinge lower cover Install (Kept) 3

1
- seal plate Install (Kept) 4

**FIGURE 4: ACCESS PANEL REMOVAL & INSTALLATION - RIGHT SIDE (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 45 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 5: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE**  **(SHEET 1 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 46 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 5: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE**  **(SHEET 2 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 47 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 5: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE**  **(SHEET 3 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 48 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  **CAUTION:** DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.Using hand pressure, apply force tothe mechanism alternating between theinboard and outboard direction whiledoing the inspections in the following steps. The force canbe applied at any location on the mechanism, but no morethan four inches forward of the elevator front spar. - - force Apply 1

Detailed. Look for gaps. 1
- swage ring/lug interface Inspect 2
Detailed. Look for gaps. 1
- lug/lug interface Inspect
Detailed. Look for gaps. 1
- lug/spacer interface Inspect (b) 1
- spacer Inspect 3 (a) If there is sealant in the interface, do not remove it. 1
- swage ring/lug interface Inspect 4

(c) If there is sealant in the interface, do not remove it. 1
- lug/lug interface Inspect 5

(c) If there is sealant in the interface, do not remove it. 1
- lug/spacer interface Inspect 6

(a) Using a feeler gage, make sure that there is no gap between the swage ring and the outer face of the lugsuch that a 0.005 inch feeler gage can be inserted more than 0.025 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 5: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE (SHEET 4 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 49 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (b) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger pressure and try to rotate the spacer. (c) Using a feeler gage, Make sure that there is no gap between the two nested lugs or between the inner face of the lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 5: AFT ATTACH LUG DETAILED INSPECTION - INBOARD LUG - RIGHT SIDE (SHEET 5 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 50 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 6: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE**  **(SHEET 1 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 51 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 6: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE**  **(SHEET 2 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 52 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 6: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE**  **(SHEET 3 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 53 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  **CAUTION:** DO NOT APPLY FORCE WITH ANYTHING OTHER THAN YOUR HAND. DO NOT APPLY EXCESSIVE FORCE OR YOU MAY DAMAGE THE ELEVATOR TAB CONTROL MECHANISM LUGS OR BEARINGS. A BENT LUG OR LOOSE BEARING COULD LEAD TO UNWANTED ELEVATOR TAB FREEPLAY AND THEN TAB VIBRATION WHICH COULD LEAD TO STRUCTURAL FAILURE OF THE ELEVATOR OR THE HORIZONTAL STABILIZER.Using hand pressure, apply force tothe mechanism alternating between theinboard and outboard direction whiledoing the inspections in the following steps. The force canbe applied at any location on the mechanism, but no morethan four inches forward of the elevator front spar. - - force Apply 1

Detailed. Look for gaps. 1
- swage ring/lug interface Inspect 2
Detailed. Look for gaps. 1
- lug/lug interface Inspect
Detailed. Look for gaps. 1
- lug/spacer interface Inspect (b) 1
- spacer Inspect 3 (a) If there is sealant in the interface, do not remove it. 1
- swage ring/lug interface Inspect 4

(c) If there is sealant in the interface, do not remove it. 1
- lug/lug interface Inspect 5

(c) If there is sealant in the interface, do not remove it. 1
- lug/spacer interface Inspect 6

(a) Using a feeler gage, make sure that there is no gap between the swage ring and the outer face of the lugsuch that a 0.005 inch feeler gage can be inserted more than 0.025 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 6: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE (SHEET 4 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 54 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT MORE DATA**  **QTY IDENTIFICATION**  **NAME TASK**  **STEP** (b) As you apply force to the mechanism alternating between the inboard and outboard direction, use finger pressure and try to rotate the spacer. (c) Using a feeler gage, Make sure that there is no gap between the two nested lugs or between the inner face of the lug and the spacer such that a 0.005 inch feeler gage can be inserted more than 0.050 inch. Do the inspection within the interface area shown in bold. Apply force to the mechanism alternating between the inboard and outboard direction as you use the feeler gage.

**FIGURE 6: AFT ATTACH LUG DETAILED INSPECTION - OUTBOARD LUG - RIGHT SIDE (SHEET 5 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 55 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT FIGURE 7: DETERMINING IF REPLACEMENT MECHANISM IS NOT BOEING BUILT**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 56 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Look in both areas shown. Look for Part number 251A2430- 15, 251A2430-16, 251A2430-17 , or 251A2430 -18 1
- Part Number Inspect 1

Within 0.5 inch of the part number,look for MFR (manufacturer) number of 468280. 1
- MFR number Inspect 2

**FIGURE 7: DETERMINING IF REPLACEMENT MECHANISM IS NOT BOEING BUILT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: April 16, 2010 737-27A1297 57 of 57 **BOEING SERVICE BULLETIN 737-27A1297 ALERT**  **ALERT**