June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 1 of 198 ALERT ALERT 

### Commercial **Airplane Group**  

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1166** Date: June 30, 1994 Revision 2 May 25, 2006 ATA System: 5311
**SUBJECT:** FUSELAGE - Frames - Body Station 727 Outboard Chord at Stringer 18A, Inspection and Preventive Modification 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 1994 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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, BBJ, DC-8, DC-9, DC-10, MD-10, MD-11, MD-80, MD-88, MD-90, and the red-white-and-blue 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in writing by Boeing.**BLANK PAGE** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 2 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BLANK PAGE**Table of Contents** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 3 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**Table of Contents** Revision Transmittal Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1. PLANNING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A. Effectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1. Airplanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 H. Weight and Balance Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 2. Data supplied with this Service Bulletin: . . . . . . . . . . . . . . . . . . . . . . . . . 76 3. Installation Drawings Used in the Preparation of this Service Bulletin: . . . . . . . . . . 78 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . 78 2. MATERIAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 C. Parts Necessary For Each Airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 2. Parts and Materials Supplied by the Operator: . . . . . . . . . . . . . . . . . . . . . . 105 3. Parts Modified and Reidentified: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 4. Parts Removed and Not Replaced: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 D. Parts Necessary to Change Spares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 F. Special Tooling Necessary to do this Service Bulletin . . . . . . . . . . . . . . . . . . . . . 108 3. ACCOMPLISHMENT INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 B. WORK INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 10 FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 127 FIGURE 2: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 128 FIGURE 3: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 129 FIGURE 4: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 130 FIGURE 5: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 131 FIGURE 6: THIS FIGURE WAS DELETED AT REVISION 2 . . . . . . . . . . . . . . . . . . . . . . 132 FIGURE 7: EXTERNAL ULTRASONIC INSPECTION OF THE STA 727 FRAME OUTBOARD CHORD FORWARD FLANGE - GROUPS 1 THROUGH 11, CONFIGURATIONS 1 AND 4. . . . 133 FIGURE 8: EDDY CURRENT INSPECTION - GROUPS 1 THROUGH 11, CONFIGURA TION 1. . . . 136 FIGURE 9: SURFACE HFEC INSPECTION - GROUPS 1 THROUGH 11, CONFIGURA TION 4. . . . 138 FIGURE 10: OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE STA 727**Table of Contents** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 4 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
OUTBOARD CHORD FORWARD FLANGE. . . . . . . . . . . . . . . . . . . . . . . 140 FIGURE 11: AUXILIARY CHORD INSPECTION - GROU PS 1 THROUGH 3, CONF IGURATION 3. . 143 FIGURE 12: AUXILIARY CHORD INSPECTION - GROU PS 1 THROUGH 3, CONF IGURATION 4. . 145 FIGURE 13: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUP 1 . 147 FIGURE 14: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUPS 2, 3, 4, 5, 6, 9 AND 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 FIGURE 15: PREPARATION FOR THE STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR 153 FIGURE 16: TIME-LIMITED REPAIR - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION FOR CRACK TIP LOCATION . . . . . . . . . . . . . . . . . . . . . . 160 FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS . . . . . . . . . . . . . . . . . . . . . . . 163 FIGURE 18: INSTALL THE TIME-LIMITED REPAIR. . . . . . . . . . . . . . . . . . . . . . . . . . 168 FIGURE 19: TIME-LIMITED REPAIR - REMOVAL. . . . . . . . . . . . . . . . . . . . . . . . . . . 176 FIGURE 20: MAKE THE REPLACEMENT PARTS TO REPLACE THE TIME-LIMITED REPAIR WITH A NEW FRAME CHORD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 FIGURE 21: STRINGER S-18A OUTBOARD CHORD AFT FASTENERS - INSPECTION - GROUP 1, 2, 3, 4, 5, 6 AND 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 FIGURE 22: STA 727 OUTBOARD CHORD FORWARD FLANGE AT STRINGER 18A - EVALUATION. 185 FIGURE 23: INSTALL THE SHEAR BEAM REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . 187 FIGURE 24: AUXILIARY CHORD INSPECTION - GROUPS 1 THROUGH 3, CONFIGURATION 1; GROUPS 4 THROUGH 11, CONFIGURATION 1 AND 4 . . . . . . . . . . . . . . . . 193 APPENDIX A: ADDENDUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 5 of 198 ALERT ALERT 

### Commercial **Airplane Group**  

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1166** 

### Revision Transmittal Sheet Date: June 30, 1994 Revision 2: May 25, 2006 ATA System: 5311
**SUBJECT:** FUSELAGE - Frames - Body Station 727 Outboard Chord at Stringer 18A, Inspection and Preventive Modification

This revision includes all pages of the service bulletin.
**COMPLIANCE INFORMATION RELATED TO THIS REVISION** Federal Aviation Administration (FAA) Airworthiness Directive 95-12-17, Amendment 39-9268, is related to this service bulletin. Airplane line numbers 1000 through 3132 were added to this service bulletin effectivity. More work is necessary on airplanes changed as shown in the previous releases of this service bulletin. Further inspections as shown in this service bulletin will need to be accomplished.
**REASON FOR REVISION** This revision is sent to revise inspections, repairs, modifications and parts fabrication and to expand the airplane effectivity to cover all 737-100/200/300/400/500 series airplanes. Additional inspections are added to address new cracks found in the STA 727 outboard chord frame, STA 727 frame auxiliary chord and the stringer S-18A outboard chord. Instructions are added to modify the STA 727 frame time-limited repair into a permanent repair. Instructions are added to install a preventive modification for the S-18A outboard chord. Changes to this revision include: — Planning Information - The service history information relating to the new cracks is updated. All references are updated to reflect the inclusion of 737-300/400/500 series airplanes into the effectivity. — Material Information - New top kits are added to this service bulletin revision. — Accomplishment Instructions - Instructions are added to do new inspections, repairs and modifications. — Figures 1, 2, 3, 4, 5 and 6 are deleted. — Figures 7, 8, 9, 10, 11, 12, 13, 14, 16, 21, 22 and 24 are added to show new inspections. — Figure 15 is added to show access for the Time-limited repair. — Figure 17 is added to show the fabrication of parts for the Time-limited repair. — Figure 18 is added to show the installation of the Time-limited repair. — Figure 19 is added to show the removal of the Time-limited repair. — Figures 20 is added to show fabrication of the Time-limited repair replacement parts. — Figures 23 is added to show installation of the Shear Beam Repair. — Appendix A is revised to show the new compliance data.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 6 of 198 The data given in Notice of Status Change 737-53A1166 NSC 1 is included in this revision. Notice of Status Change 737-53A1166 NSC 1 advised operators of a revision to drawing 65C37277, sheet PL, as shown in ADCN 3, supplied with this service bulletin. Paragraph I.A., Effectivity, shows changes of airplane operators. Each operator should examine the Effectivity paragraph for changes. Vertical lines are put on the left edge of each page, except in Paragraph I.A., Effectivity, to show the location of important changes. Pages with a revision number and date, but no vertical lines, have no important changes.
**REVISION HISTORY**
Initial Release: June 30, 1994 Revision 1: May 25, 1995 Revision 2: May 25, 2006June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 7 of 198 ALERT ALERT 

### Commercial **Airplane Group**  

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1166** 

### Summary Date: June 30, 1994 Revision 2 May 25, 2006 ATA System: 5311
**SUBJECT:** FUSELAGE - Frames - Body Station 727 Outboard Chord at Stringer 18A, Inspection and Preventive Modification

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** The changes shown in this service bulletin will decrease the probability of cracks in the frame at Station (STA) 727 where Stringer (S)-18A is attached. This area is a primary structural element. Operation with cracks in the frame will decrease the structural integrity of this area. Unscheduled downtime can be necessary to replace a frame that has a crack. Cracks in the S-18A chord are not a safety concern. Several operators have reported numerous cracks on multiple airplanes in the STA 727 frame outboard chord, where the S-18A outboard chord is attached. The cracks ranged from 0.016 inches, to a severed chord. Cracks initiate common to the 3 fastener holes or close vicinity to the fastener holes and on the forward edge of the frame outboard chords. For the fastener holes susceptible to cracking, several elongated holes were also found. Airplanes have accumulated between 20,000 - 85,000 flight-cycles and 27,000 - 74,000 flight hours. Previous revisions of this service bulletin inspected for cracks on airplanes with 7075-T6 frame outboard chords (Line Number 1-999) only. Since the release of Rev 1, seven operators have reported cracks in 7075-T73 chords with 20,000 - 52,000 flight-cycles. As a result of these new findings, this revision of the service bulletin expands the effectivity to include airplanes with 7075-T73 frame outboard chords. The cracks were caused by fatigue; for line number 1-999 airplanes (7075-T6 frame outboard chord), fretting of adjacent parts contributed to the initiation of the fatigue damage. Three operators have reported four cracks in the radius of the 65-46547-9 Auxiliary Chord on three airplanes. 1.00 inch cracks were reported. Airplanes have accumulated between 46,000 - 85,000 flight-cycles and 41,000 - 64,000 flight hours.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 8 of 198 Several operators have reported numerous cracks on multiple aircraft in the S-18A outboard chord common to the fastener locations just aft of STA 727. Airplanes have accumulated between 30,000 - 76,000 flight-cycles and 32,000 - 65,000 flight hours. One operator found one crack on one airplane in the S-18A chord, forward of STA 727 in the lower fastener row. The aircraft had 68,000 flight-cycles and 71,000 flight hours. Cracks have been found in S-18A chord sections of thickness at STA 727 of 0.33 inches or less. The cracks were caused by fatigue. Four operators have reported four cracks on three aircraft with a "T" profile S-18A outboard chord. The vertical flange of the chord has cracked at the base, at the vertical flange run-out, near STA 727. These cracks can grow along the base of the vertical flange in the radius. These cracks have been associated with S-18A outboard chord installation pre-loads. As part of a service bulletin validation program, the inspection, frame chord replacement, and preventive modification was completed on airplane PG576 before the initial release of this service bulletin. Boeing Service Related Problem (SRP) 737-SRP-53-0162 is related to this service bulletin. Federal Aviation Administration (FAA) Airworthiness Directive AD 95-12-17, is related to this service bulletin. The FAA is considering additional rule making that will make the compliance tasks and times given in Revision 2 of this Service Bulletin mandatory. Boeing Structural Item Interim Advisory (SIIA) 737-131 is related to this service bulletin.
**ACTION** Do inspections of the outboard chord of the frame at STA 727 where S-18A is attached. Look for cracks. Do the inspections at the times given in the Compliance section. If cracks are found in the outboard chord of the frame at STA 727, install the time-limited repair or replace the chord and, optionally, install the preventive modification. If no cracks are found, install the preventive modification or do the repeat inspections. Do the inspections at the times given in the Compliance section until the STA 727 frame preventive modification is installed. If the STA 727 frame outboard chord preventive modification is installed with an edge margin greater than or equal to 1.7D, there are no further inspection requirements per this bulletin for the STA 727 frame outboard chord. Do an inspection of the STA 727 frame auxiliary chord for cracks. Do the inspection at the times given in the Compliance section. If cracks are found, repair before further flight. Contact Boeing for repair data. If no cracks are found, but a permanent frame chord modification has not been installed, continue inspections at the times given in the Compliance section. If no cracks are found and STA 727 frame outboard chord modification strap has been installed, and the frame chord is 7075-T73, there are no further inspection or modification requirements for the STA 727 frame auxiliary chord. Do inspections of the outboard chord of S-18A at STA 727. If cracks are found in the outboard chord of S-18A, do the S-18A repair. If no cracks are found in the outboard chord of S-18A, install the S-18A Preventive Modification. If the S-18A modification or repair is installed, there are no further inspection requirements per this bulletin for the S-18A outboard chord. More work is necessary for operators that have replaced the outboard chord of the frame at STA 727 as shown in Service Bulletin 737-53-1088 and who have not installed a permanent modification. Refer to the Compliance section.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 9 of 198 **EFFECTIVITY** All 737-100/200/200C/300/400/500 series airplanes. See paragraph 1.A., Effectivity.
**COMPLIANCE** See Service Bulletin Paragraph 1.E. for compliance information.
**INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service bulletin.
**MANPOWER** Refer to Paragraph I.G. Manpower.
**MATERIAL INFORMATION** Boeing Supplied Kits Refer to Paragraph 2.A., Material - Price and Availability.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 10 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

STRINGER 18A FOR CRACKS IN INSPECT AREA INSPECTIONS 727 FRAME FOR STA

AFT SKIN

FWD SKIN

CRACKS FLANGE FOR FORWARD 727 FRAME INSPECT STA

FLANGE EDGE OF FORWARD INSPECT

INSPECTION CHORD AUXILIARY FOR FOR CRACKS CHORD RADIUS AUXILIARY INSPECT CHORD AUXILIARY

CRACK TYPICAL



### B CHORD AUXILIARY CHORD FRAME AFT SKIN

WEB BULKHEAD

UP FWD

VIEW FROM INSIDE CARGO BAY SEE A



### A SEE BD41500 NOT SHOWN STRUCTURE SUPPORT FAIRING

PLATE) CHORD OF STRINGER 18A IS A FLAT (ON MOST AIRPLANES THE OUTBOARD STRINGER 18A

CRACKS TYPICAL

LEFT SIDE SHOWN RIGHT SIDE OPPOSITE (WING-TO-BODY FAIRING NOT SHOWN) STA 727

WEB BULKHEAD STA 727

CRACK TYPICAL CHORD ONLY) S-18A OUTBOARD A 'T' PROFILE (AIRPLANES WITH TYPICAL CRACKJune 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 11 of 198 ALERT ALERT 

### Commercial **Airplane Group**  

# 737

**ALERT ALERT**  

# Service Bulletin

**Number: 737-53A1166** Date: June 30, 1994 Revision 2: May 25, 2006 ATA System: 5311
**SUBJECT:** FUSELAGE - Frames - Body Station 727 Outboard Chord at Stringer 18A, Inspection and Preventive Modification

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 35005-244RS for data about this change.
**NOTE:** As the group configurations are described below, a single airplane may meet the description for two separate configurations. The left side configuration may be different than the right side configuration.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 12 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

**GROUP CONFIGURATION DESCRIPTION** 1 - 737-100/200/200C Series airplanes, line numbers 1-310. These airplanes have a "T" profile S-18A Outboard Chord with a thickness of 0.20 inch at STA 727. 1 Airplanes with a replaced Station (STA) 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 13 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2 - 737-200/200C Series airplanes, line numbers311-972. These airplanes have a Flat Strap S18A Outboard Chord with a thickness of 0.20 inch at STA 727. 1 Airplanes with a replaced Station (STA) 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 14 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

3 - 737-200/200C Series airplanes, line numbers 973-999 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.33 inch at STA 727, early skin panels and early fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 15 of 198 4 - 737-200/200C Series airplanes, line numbers 1000-1585 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.33 inch at STA 727, early skin panels and early fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 16 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

5 - 737-300/500 Series airplanes, line numbers 1001-2664 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.33 inch at STA 727, early skin panels and later fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 17 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

6 - 737-300/500 Series airplanes, line numbers 2667-3130 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.33 inch at STA 727, later skin panels and later fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 18 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

7 - 737-400 Series airplanes, line numbers 1487- 2657 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.40 or 0.45 inch at STA 727, later skin panels and early fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 19 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

8 - 737-300/400/500 Series airplanes, line numbers 2665-3132 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.40 or 0.45 inch at STA 727, later skin panels and later fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 20 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

9 - 737-300/500 Series airplanes, line numbers 2938-2942 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.33 inch on one side and 0.40 or 0.45 inch on the opposite side at STA 727, with later skin panels and later fairing support structure. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 21 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

10 - 737-300/500 Series airplanes, line numbers 1842-1896 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.33 inch at STA 727, early skin panels, later fairing support structure and short edge margin repair installed per 65C36009 Detail 7. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 22 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

Airplane models:
737-100 737-200 737-200C 737-300 737-400 737-500 IDENTIFICATION BY CUSTOMER, CUSTOMER CODE, GROUP AND VARIABLE NUMBER ADAM AIR (DAM) 5 PP508 PP840 6 PU301 7 PM556 PW009 PW119 ADC AIRLINES (ADN) 2 PJ118–PJ119 3 PN033–PN034 AEGEAN AIRLINES S.A. (CRM) 5 PM392 PS608 6 PR028 PR030 PS961 7 PW002 PW046 PW053 PW157 PW261 PW502 PW564 8 PV287 PW276 PW289 11 - 737-400 Series airplanes, line numbers 1844- 1908 that have a Flat Strap S-18A Outboard Chord with a thickness of 0.40 or 0.45 inch at STA 727, later skin panels, early fairing support structure and short edge margin repair installed per 65C36009 Detail 7. 1 Airplanes with a replaced STA 727 Frame Outboard Chord and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 2 Airplanes with the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 3 Airplanes without the STA 727 Frame Outboard Chord replaced and with the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. 4 Airplanes without the STA 727 Frame Outboard Chord replaced and without the STA 727 Frame Outboard Chord Preventive Modification installed as shown in previous revisions of this bulletin. **GROUP CONFIGURATION DESCRIPTION**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 23 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AER LINGUS (ARL) 5 PT167–PT168 AERGO CAPITAL LIMITED (CLJ) 1 PY031 2 PK462 PK468 PK772 PK820 4 PK528 PN405 AERO CONTRACTORS OF NIGERIA (NCC) 5 PQ194 PQ196 AERO CONTROLS (AEO) 1 PG312 PG629 AEROCONDOR (EDR) 2 PL401 4 PN491 AEROGAL/GALAPAGOS AIRLINES (ERG) 2 PK715 PK827 3 PN030 4 PL624–PL625 AEROLINEAS ARGENTINAS (ARG) 1 PG584–PG585 PH705–PH708 PH741–PH742 PY007 2 PH743 PK102–PK103 PK735–PK737 PK739–PK740 PK747 PN112 4 PK750–PK751 PK755 PK757 PK760–PK765 PN113 5 PP948 PT042 PT303–PT306 PT309 PT509–PT510 AEROLINEAS AUSTRAL CHILE S.A. (LUT) 2 PL405 PM141–PM142 AEROSERVICE (SRI) 1 PL742 2 PL743 AEROSUCRE (SUS) 1 PY341 2 PY201 PY451 AEROSUR (REO) 2 PK594 AEROSVIT (UKA) 2 PK564 5 PP924 PQ284 PT614–PT615 7 PW265 PW591–PW592 PW595–PW596 AEROVISTA GULF EXPRESS (GXP) 2 PL556June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 24 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AIGLE AZUR (AZU) 5 PP962 AIR ALGERIE (ALG) 2 PK633–PK634 PL722 PL724 PY051 PY053 AIR ATLANTA ICELANDIC (AID) 5 PP352 PP913 PQ222 7 PW011 PW094 AIR AUSTRAL (AUX) 5 PT215 6 PS621 AIR BERLIN (BER) 8 PJ811 PW524 PW528–PW530 AIR CANADA (ACN) 2 PK679–PK680 AIR CANADA JAZZ (ANI) 2 PK310 AIR CHINA (BEJ) 5 PP521–PP522 PQ361–PQ364 6 PQ345–PQ346 PQ373 PQ438 PQ447 PQ971 PQ975 PS957 AIR CHINA INNER MONGOLIAN (IML) 5 PQ365–PQ366 PQ370 PS614–PS617 6 PQ372 PQ988 PQ990 AIR CHINA SOUTHWEST BRANCH (XIN) 5 PP631–PP634 PQ401–PQ406 PQ408–PQ410 6 PS811 AIR CHINA TIANJIN BRANCH (TJA) 5 PQ367–PQ369 PQ371 AIR CORRIDOR (KRD) 2 PK749 AIR EUROPA (ARE) 7 PW266 AIR FRANCE (AFA) 5 PT214 PT501–PT508 PT511–PT514 AIR GABON (GBN) 2 PY191June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 25 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AIR GUINEE (GNE) 2 PY651 4 PN456 AIR HORIZONS (AHZ) 1 PY004 5 PP965 PP967 7 PW065 AIR MADAGASCAR (MAD) 1 PG375 2 PL793 5 PP852 PQ297 PQ299 AIR MALAWI (AML) 5 PS602 AIR MALTA (MLT) 5 PQ791 PQ793 6 PS873–PS874 AIR MEDITERRANEE (AMV) 1 PG028–PG029 PY301 AIR NAMIBIA (NAM) 2 PK355 PK731 4 PN492 AIR NAURU (NAU) 7 PW556 AIR NEW ZEALAND (ANZ) 5 PS651 6 PQ997 PR041 PR062–PR066 PR077–PR080 PR101 PS866–PS868 AIR NIPPON (ANK) 5 PT053 PT060 PT063–PT064 6 PT126 PT128–PT131 PT871–PT886 7 PW026 8 PJ817 AIR NORTH YUKON'S AIRLINE (AND) 2 PK596 PK599June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 26 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AIR ONE (ADH) 2 PK432 4 PK933 PK938 5 PM410–PM411 PQ228–PQ229 6 PQ347–PQ348 7 PV231–PV234 PV236–PV237 PW041 PW043 PW052 PW054 PW106 PW111–PW112 PW115 PW267 PW288 PW302 PW317 PW526 8 PW831 PW851 AIR PHILIPPINES (PHP) 1 PG001 PG039 PG061–PG062 PG066 2 PK099 PK541–PK542 PN021–PN022 PN025 3 PN029 PN031 PN038 AIR PLUS COMET (PLD) 5 PP904 PP912 AIR SAHARA (SAQ) 5 PQ306 6 PR012 PR021–PR022 7 PW061 PW064 PW066 8 PW264 PW273 AIR SENEGAL INTERNATIONAL (SNG) 5 PT023 AIR SLOVAKIA (SLO) 4 PK936 AIR TANZANIA (TNZ) 2 PY611 AIR VANUATU (VAN) 6 PQ454 AIR ZIMBABWE (ZMB) 4 PN431–PN433 AIRASIA BERHAD (ASW) 10 PM391 5 PM385 PM388 PM390 PM397–PM398 PP002 PP021 PP023 PP234 PP406–PP409 PP411–PP412 PP419 PP421 PP471 PP473 PP504 PP509 PP516–PP517 PP676–PP677 PP684 PP686–PP687 PP848 PP920 PQ184 PQ332 PS657 6 PQ448June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 27 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AIRBALTIC CORPORATION (BCB) 5 PT005 PT161–PT163 6 PU311 PU313 AIRCRAFT 23383, LLC. (LSG) 5 PP028 AIRCRAFT MAINTENANCE CORP. (AMF) 2 PK254 AIRFAST INDONESIA (PTF) 1 PY343 2 PK562 4 PN481 AIRTRAN AIRWAYS (CQT) 2 PK697 AIRWORK NZ (ANX) 2 PY741 5 PQ026 AIRZENA (GEI) 5 PP044 PT611 7 PW262 ALASKA AIRLINES (ASA) 2 PY112 PY134 PY270 PY461–PY462 4 PY463 PY593–PY594 7 PJ301–PJ302 PW116 PW231–PW249 8 PJ601–PJ615 PW250–PW252 ALBARKA AIR SERVICES (ABF) 2 PL111 ALOHA AIRLINES (ALO) 2 PK905 PK926 PY231 3 PN085 4 PK934–PK935 PL626 PM251 PM253 PN473 PY592 PY595 PY721 ALTER BAIL AVIATION (ABH) 2 PK215 PK359 AMERICA WEST AIRLINES (AMW) 2 PL081 PL559–PL560 5 PP022 PP029 PP183–PP187 PP189 PP194–PP195 PP197–PP199 PP383 PP472 PP474–PP475 PP831 PP833–PP834 PP846 PP891 PP893 PP895 PP898–PP899 PP901 PP931–PP934 PP936 PS666–PS669 6 PR067June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 28 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AMERICAN FALCON AIR (FAK) 2 PK464 PL026 AMERISTAR AIR CARGO (CGG) 1 PY345–PY346 2 PK221 PK560 PM051 APOLLO AVIATION CAPITAL, LLC. (APV) 1 PL761 ARAL (RII) 7 PW031 ARKIA ISRAELI AIRLINES (ARK) 2 PK822 PL402 PL404 PL414 ASIA AIRLINES (YDO) 1 PY005 2 PY135 ASIANA AIRLINES (AAR) 5 PT851 6 PT852–PT853 7 PW283 PW286 8 PV204–PV206 PV208 PV226–PV229 ASTRAEUS, LTD. (AUA) 5 PP845 PP929 PP935 PS605 6 PQ994 ATA AIRLINES, INC. (AAT) 5 PQ188 PQ190 ATA ATLANTICO TRANSPORTE AEREO (AUI) 1 PY003 PY321–PY322 PY361 ATLANTIC AIRLINES (LNL) 2 PL008 PL010 PL622–PL623 ATLAS BLUE (ABT) 11 PW632 7 PW631 PW633–PW636 AURELA (URE) 5 PQ307 AUSTRAL - CIELOS DEL SUR (ALA) 2 PN103–PN104 PN110–PN111 4 PN114–PN115 PN117 AUTOMATIC 9W (TMW) 10 PQ191 5 PQ193 PQ195June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 29 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** AUTOMATIC LLC (AUM) 2 PJ114–PJ115 PK502 PK504 PK801–PK804 PK821 PK824 PK901 PK974 AVENSA (AVN) 2 PK042 AVIACSA AEROEXO (AEJ) 2 PK289 PK598 PK625–PK626 PM101–PM102 PM106–PM107 PM115–PM117 4 PK216–PK220 PM181 PN454 AVIATION CAPITAL GROUP (CGP) 2 PK286 AVIATION CONSULTANTS (ACT) 1 PG037 PY001 2 PK546 AVIOGENEX (AVG) 4 PN501 AVIOR (AWD) 2 PK549 PK591 AVOLAR (AOL) 5 PT001 AXIS AIRWAYS (AXY) 5 PP947 PQ301 PQ341 7 PW033 BAHAMASAIR (BAH) 2 PK672–PK673 PL501 PL506 BALI AIR (ZBL) 2 PL504 BASIC CAPITAL MANAGEMENT (BCM) 4 PN455 BATAVIA AIR (BTV) 2 PJ107 PJ112 PK252 PK283–PK284 PK305 PK360 PK514 PK563 PK617 PK622 PK635 PK711 PK825 4 PK515 5 PS631 7 PW005 PW015 PW032 PW575 BAYU INDONESIA AIR (BAY) 2 PK561June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 30 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** BELAVIA (ITU) 6 PT722 PT971 BELLVIEW AIRLINES (BEB) 2 PK203 PK612 PK872 PL028 BLUE AIR (BTR) 10 PT211 5 PS618 BLUE DART AVIATION (BDA) 2 PK231–PK232 PL451 4 PM281 PN521 BLUE PANORAMA AIRLINES (BPA) 11 PW518 7 PW284 PW519 PW741–PW742 BLUEBIRD CARGO (BLS) 5 PM383 PQ242 PQ342–PQ344 BMI BRITISH MIDLAND (BMA) 5 PQ291–PQ292 PQ431 PT186–PT188 PT701–PT703 6 PP520 PQ433–PQ435 PQ974 PQ992 PQ996 PS625 PS861 BOEING (TBC) 1 PG051 PG215 BOURAQ AIRLINES (PTB) 2 PK255 PK302–PK303 PK307–PK309 PK501 PK913 PK918–PK920 PK931 PL409–PL410 PM021 BRA TRANSPORTES AEREOS (BRW) 5 PP907 PP946 PP984 PQ226 PQ243 PQ260–PQ261 7 PW020–PW021 PW504 BRITISH AIRWAYS (BAB) 10 PT295 5 PM399 PP841–PP842 PQ283 PQ305 PT009 PT021 PT183 PT185 PT307–PT308 6 PT515–PT516 7 PW101 PW301 PW305–PW308 PW312 PW314–PW315 PW318–PW327 BULGARIA AIR (BLD) 5 PQ224–PQ225 PQ262 PT170 PT427 PT437 6 PR025–PR026June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 31 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** BURAQ AIR (BQA) 2 PL723 PL725 C.I.T. LEASING CORPORATION (TCI) 5 PP836 PP964 7 PW562 CANADIAN NORTH (ANP) 2 PL415 PY152–PY154 PY422 PY441 CANJET (CNJ) 5 PT424–PT426 PT428–PT429 PT434–PT435 PT438 PT616 CAYMAN AIRWAYS (CAY) 2 PJ009 PY244 4 PK753 5 PQ293 PQ481 CHANCHANGI AIRLINES (CGI) 2 PL412 PL416–PL417 CHANNEL EXPRESS (AIR SERVICES) (CEX) 5 PP908–PP909 PP914 PQ027 PQ030–PQ039 PQ051–PQ052 PQ054–PQ055 PQ058–PQ059 CHARTER AIR (FIH) 6 PS630 PS871 CHILEAN AIR FORCE (CHF) 5 PQ053 6 PT996 CHINA EASTERN AIRLINES (CEA) 6 PQ977 PQ979 PQ981 PR141–PR143 CHINA EASTERN AIRLINES WUHAN (WUH) 5 PQ472 PQ491–PQ492 6 PR081–PR082 PR131 CHINA EASTERN YUNNAN AIRLINES (YUN) 5 PP651–PP652 PQ263 PQ411–PQ412 6 PQ414–PQ415 PQ417–PQ418 PS622–PS623 PS628 8 PQ416 CHINA SOUTHERN AIRLINES (GUN) 5 PM408–PM409 PM412 PM541–PM544 PM547 PM549 PQ252–PQ255 PQ407 PQ479–PQ480 PS836–PS837 PS841–PS844 PT041 PT043–PT049 PT052 PT061–PT062 6 PR121–PR122 PS845–PS846June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 32 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** CHINA UNITED AIRLINES (CUL) 5 PP728–PP729 PQ288–PQ289 PS609–PS610 6 PS896–PS897 CHINA XINHUA AIRLINES (XIH) 5 PM546 PQ264 PQ804–PQ805 PS856 6 PR001 8 PW852–PW854 CHINA XINJIANG AIRLINES (XIJ) 5 PM545 PM548 CIRRUS AIRLINES (CSG) 5 PT146 CIS AIR HOLDINGS (CIS) 1 PG217 COMAIR LIMITED (CML) 2 PK734 PK738 PK744 PK748 PK904 PK907 4 PK754 PK758 5 PQ001 PQ003–PQ006 PQ008 PQ010 7 PW303 PW310–PW311 CONOCOPHILLIPS ALASKA, INC. (ATR) 2 PK610 4 PN452–PN453 CONTINENTAL AIRLINES (CAL) 5 PP671–PP675 PP678 PP680–PP683 PP685 PP688–PP699 PP701 PP703–PP710 PP712–PP726 PP730 PP732–PP733 PT801–PT818 PT826–PT828 6 PT819–PT825 PT829–PT834 PT901–PT905 PT907–PT930 CONVIASA S.A. (VSS) 5 PQ117 PS604 CORENDON AIRLINES (HVA) 5 PQ286 6 PQ451 CORSAIR (COR) 7 PW661–PW662 CSA (CSA) 5 PT184 PT301–PT302 PT617–PT621 6 PT136 PT138 PT981–PT985 7 PW039 PW102 PW268 PW304 PW309 PW517 8 PJ816 PV302 PW431–PW435June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 33 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** CSC TRANSPORT (CTC) 7 PW007 DASAB AIR (DSB) 2 PN024 3 PN036 DBA (DBA) 5 PP507 PP511 PP515 PP838 PP961 PQ119 PQ152 PS655 6 PR015–PR017 DELTA AIR LINES (DAL) 3 PN131–PN135 4 PN136–PN163 PN401–PN404 PN407–PN420 5 PP231–PP233 PP235–PP243 PP506 PQ086 PQ231–PQ232 DODSON AVIATION (DOO) 1 PJ032 DOLPHIN AIR (FDN) 2 PL151 PY241 EARTH AIRLINES (ETL) 1 PG352 EAS AIRLINES NIG (EAV) 2 PL453 3 PN032 4 PK681 EAST AFRICAN AIRLINES (EAB) 2 PL023 EASYJET (EZY) 5 PP510 PP518–PP519 PS652 6 PR003–PR004 PR167–PR172 PS971 PS974–PS978 EG&G TECHNICAL SERVICES (EGN) 2 PJ205 PJ207–PJ210 PJ218 PL763 EGYPTAIR (EGP) 1 PG026 5 PT561 PT563–PT565 ESTAFETA (EST) 2 PY131 PY275 3 PY056–PY057 5 PP825–PP826June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 34 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** ESTONIAN AIR (ENA) 5 PT010 6 PT137 PT716–PT717 PU312 ETHIOPIAN AIRLINES (ETH) 4 PN512 EUROATLANTIC AIRWAYS (MAE) 5 PP985 EUROPE AIRPOST (EUE) 5 PP392 PP832 PP925 PP951–PP952 PQ421 PQ771–PQ772 PS607 PS641–PS644 6 PR096 EUROPEAN AVIATION AIR CHARTER (EUL) 2 PK044–PK046 PK048–PK050 PK053 PN001 PY273 EXECUTIVE JET AIRCRAFT COMPANY (EXF) 2 PL441 EXPORT RESTRICTED AIRPLANES (YWV) 1 PA002 PG021 PG041 PG074 PG218–PG219 PG224 PG305 PG307–PG308 PG310–PG311 PG574 PH731 PJ002 PJ102 PY021 2 PJ003 PK391 PL758 PY022 PY141–PY142 EXTRA AIRWAYS (CIN) 1 PG279 11 PW503 2 PN083 3 PN084 PN086 7 PW117 PW761 FAA (FAA) 2 PL768 FACTS AIR (FAD) 1 PX701 FALCON AIR (FLK) 5 PS636–PS638 FALCON AIR EXPRESS (FAX) 5 PP897 FALCONBRIDGE (NAD) 2 PY612June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 35 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** FASCO AIRWAYS (EAO) 1 PG228 FEDERATIVE REPUBLIC OF BRAZIL (BRZ) 2 PK068–PK069 FINOVA (GRB) 4 PK759 FIRST AIR (BRS) 2 PK358 PL407 PY133 PY281 PY421 FISCHER AIR POLAND (FSP) 6 PS973 FLY AIR (FHA) 5 PQ281 FLYGLOBESPAN.COM (FGS) 6 PS962–PS963 FLYING CARPET (FYC) 4 PM064 FLYME (FMA) 5 PP393 PP902 PP910–PP911 FREEDOM AIR INTERNATIONAL (SPT) 6 PR045 FRONTIER AIRLINES (FRO) 2 PK495 FUTURA (FUA) 5 PP430 PP892 PQ197 7 PW034–PW035 PW047–PW048 PW114 PW501 PW527 PW561 GARUDA INDONESIA (GIA) 5 PM393–PM394 PM404 PQ285 PQ487 PS606 6 PQ986–PQ987 PR061 PR068–PR072 PR091–PR092 PS956 PT681–PT682 PT684–PT685 7 PV271–PV272 PW022 PW028 PW067 PW461–PW467 8 PV301 PW272 PW441–PW450 PW525 9 PT683 GARY 737 LLC (BHA) 2 PL745June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 36 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** GE AVIATION MATERIALS (GML) 5 PP001 GE CAPITAL CORPORATION (GEF) 1 PG220–PG221 PG651–PG652 2 PK026–PK027 PK256 PK465–PK467 5 PM407 7 PW051 GENERIC CUSTOMER/SUPPLIER (XXX) 2 PK274 GERMANIA (GER) 5 PP503 PQ087 PQ230 PQ233–PQ237 GLOBAL AIR (YCH) 2 PK548 PL013 GOL AIRLINES (GOT) 5 PQ056 PQ123–PQ124 PQ144–PQ145 PQ159–PQ160 PQ162–PQ163 HAINAN AIRLINES (HNA) 5 PQ088–PQ091 PQ156–PQ157 PQ473–PQ474 PS611 PS613 6 PQ475 PR005 PR010 7 PV203 PW093 8 PV356–PV357 PW086–PW088 HAMRA AIR (HMA) 5 PP420 HAPAG LLOYD EXPRESS (HLX) 5 PT104 HAPAG-LLOYD FLUG (HAP) 10 PT101 5 PT102–PT103 PT105 HEMUS AIR (HEU) 7 PM554 HEWA BORA AIRWAYS (EXD) 1 PG274 HOLA AIRLINES (HLB) 10 PQ304 5 PP894 ICARO (IKA) 2 PK742June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 37 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** INDIAN AIR FORCE (IDF) 1 PH712–PH713 3 PM016–PM017 INDIAN AIRLINES (IND) 2 PK237–PK240 PM001–PM006 PY631 INTAL AIR (IRT) 2 PY242 PY274 INTER AIR (ITI) 1 PY046–PY047 INTERLEASE AVIATION (ILA) 1 PG210 INTERNATIONAL AIR LEASES (IAL) 1 PL803 INTERNATIONAL AIR PARTS (IAO) 1 PG580 INTERNATIONAL TRANSPORT (YIT) 1 PG304 INT'L AVIATION SERVICES GROUP (ISG) 2 PK318 ISRAEL AIRCRAFT INDUSTRIES (IAI) 1 PG575 2 PK692 JAL INTERNATIONAL (JAL) 8 PW411–PW418 JANCO AIRCRAFT AND ENGINES (JNC) 4 PM282–PM283 JAPAN TRANSOCEAN AIR (SWL) 7 PW401 PW515–PW516 PW520 PW681–PW683 8 PW402–PW408 PW521 JAT YUGOSLAV AIRLINES (JAT) 5 PP771–PP779 PQ241 7 PV023–PV024 PW092 JATAYU AIR (JAJ) 1 PG068 2 PJ117 PK257 PK511 4 PK937 JERRY CONWAY (JCW) 2 PK552June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 38 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** JET AIRWAYS (JPL) 7 PW215–PW216 8 PV207 PV209 PW421–PW424 JET FREIGHT (JFO) 5 PQ158 PQ161 JET MIDWEST (JMI) 2 PK558 JETALLIANCE (JFB) 6 PS862 JETCONNECT LIMITED (JCL) 5 PQ002 PQ007 PQ009 PQ011–PQ015 7 PW537–PW539 JETRAN INTERNATIONAL, LTD. (JTI) 1 PC005 2 PK306 PK592–PK593 PK601 PK605 PK607 PL552 PL557 PM103–PM105 3 PM118–PM119 PN035 5 PP009–PP010 PP013 7 PV041–PV043 JETSCAPE LEASING (IAN) 7 PW091 JETSTAR AIRCRAFT SALES (JTS) 1 PG306 JORDAN AVIATION (JOR) 4 PY410 5 PP896 PQ187 K.A.B. (KBH) 2 PK315 KALININGRADAVIA (JSK) 5 PP305 PP801 PP843–PP844 PP916 PQ302 KARTHAGO AIRLINES (KAG) 5 PP926 PP928 PP930 6 PQ432 PR029 KENYA AIRWAYS (KEN) 2 PK641–PK642 PY272 6 PR031–PR034 KITTY HAWK AIR CARGO (KHC) 5 PM382 PM396 PM405 PP847 PP862 PQ221 PQ223June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 39 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** KLM - ROYAL DUTCH AIRLINES (KLM) 5 PP861 PP863–PP866 PP868–PP869 PP871–PP875 6 PP876–PP877 7 PW014 PW017 PW611–PW622 KRASAIR (ZXD) 5 PQ792 LAB (LAB) 6 PQ951 LAC (CQC) 2 PY113 LAM (LAM) 4 PL455–PL456 PN451 LAN AIRLINES (LAN) 1 PJ104 2 PJ006 PJ105–PJ106 PJ109 PK212 PK431 PK433 PK524–PK525 PK745 PK775 PK902–PK903 PK908–PK912 PK914–PK916 PK921–PK923 PK927 PL025 LAPA ARGENTINA (LAZ) 2 PK051 LIBYAN AIRLINES (LAA) 2 PK361 LINA CONGO (LNA) 2 PY411 LINEAS AEREAS AZTECA (AZX) 5 PP802 PP915 PP923 PP983 PP986 PQ116 LION AIR (MLI) 7 PW016 PW023 PW025 PW027 PW037–PW038 PW042 LITHUANIAN AIRLINES (LIJ) 2 PK632 PL611 5 PT169 6 PT721 PT723 PT972–PT973 LOCALEASE (LLA) 2 PK282 LOCKHEED MARTIN (LMA) 5 PQ057June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 40 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** LOGISTIC AIR, INC. (LGA) 1 PY303–PY304 LOT POLISH AIRLINES (LOT) 5 PT651–PT656 6 PQ978 PQ980 7 PV281–PV284 8 PV285–PV286 LUFTHANSA GERMAN AIRLINES (DLH) 5 PQ060–PQ085 PQ092 PS701–PS703 PT331–PT360 6 PS704–PS706 LUXAIR (LUX) 5 PT671–PT672 MACEDONIAN AIRLINES, MACEDONIA (MCC) 5 PP043 MAERSK AIR (MRS) 6 PT135 MAGIC CARPET AVIATION (MCI) 5 PP991 MAGNICHARTERS (MAM) 2 PJ004 PK143 PK145 PK595 PL454 PL554 PL558 5 PQ028 PQ168 MALAYSIA AIRLINES (MAS) 7 PJ551–PJ556 PW201–PW214 PW217–PW230 8 PJ557–PJ561 MANDALA AIRLINES (MND) 2 PK354 PK463 PK614 PK636–PK637 PK874 PK925 PL027 PL061 PL421 PN002 7 PW004 PW010 MARANATHA LEASING CORPORATION (MNT) 1 PG436 2 PK201–PK202 PL011 PM062 MERPATI NUSANTARA AIRLINES (PNM) 2 PK615 PK623–PK624 PK819 PK917 PK929–PK930 MEXICAN AIR FORCE (MXA) 4 PN041 MEXICO'S PRESIDENTIAL AIRCRAFT (MXG) 5 PP919 PQ155June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 41 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** MNG AIRLINES (MHK) 7 PW282 PW285 PW512 PW514 PW593 NAT AVIATION U.S.A. (NTV) 2 PK258 PK551 PK557 PK732 NATIONWIDE AIRLINES (NWR) 2 PJ007–PJ008 PK357 PK741 PK871 PK906 PK928 PK932 PL631–PL632 PN107 PN109 5 PT612–PT613 NEWJET (NES) 2 PL172 PL562 NIGERIA AIRWAYS (NIA) 2 PL785 PL788 NORTHROP GRUMMAN CORPORATION (GRU) 1 PG208 NORTHSTAR PRESIDIO MANAGEMENT (INH) 2 PK094–PK095 NORWEGIAN AIR SHUTTLE AS (NSB) 10 PP807 5 PM381 PM389 PM401–PM402 PP805–PP806 PP808 PP918 PS654 6 PQ983 PQ985 PR002 NOVA AIR (PDM) 2 PL007 PL406 OLYMPIC AIRLINES (OLY) 11 PW063 2 PM022 5 PQ298 7 PW044 PW062 PW068 PW072 PW296 PW711–PW717 PW771 ORENBURG AIRLINES (ORG) 7 PW036 OZJET AIRLINES (OZJ) 2 PK041 PK052June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 42 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** PACE AIRLINES (PIE) 1 PG075 PG203 11 PW563 2 PL001 PL502–PL503 PN102 PN105 PN108 4 PN116 5 PP181–PP182 PP196 PP835 PP837 PP867 PP870 PAKISTAN INT'L AIRLINES (PIA) 5 PP281–PP286 PS612 PEGASUS AIRLINES (PGS) 11 PW030 8 PW263 PEGASUS AVIATION, INC. (PSS) 1 PL712 2 PK043 PK233 PK235 PL403 PL413 4 PK752 PK756 PEMCO WORLD AIR SERVICES (PEF) 5 PQ154 PERUVIAN AIR FORCE (PRF) 1 PG251 PG253 PG351 6 PT517 PHILIPPINE AIRLINES (PAL) 5 PM384 PM395 PQ803 PS601 7 PM561 PW029 PW156 PHOENIX AVIATION (PHX) 1 PG578–PG579 2 PK213–PK214 PK222 PK671 PK823 PK826 PK830 4 PM252 PHUKET AIRLINES (PHK) 1 PG581–PG582 3 PN037 4 PN039 PLM INTERNATIONAL (PLI) 2 PK675 PLUNA (PLU) 2 PL201–PL203 5 PQ287 PREMIER AIRLINES (PMN) 4 PN493June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 43 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** PULKOVO AIRLINES (STG) 5 PT164–PT166 Q AVIATION (QAV) 10 PQ189 2 PK288 PK603–PK604 PK883 5 PQ192 PT397 QANTAS (QAN) 5 PQ016 7 PW531–PW536 PW540–PW547 PW557 8 PW548–PW550 QWEST AIR PARTS (QWE) 1 PG438 REPEX AIRLINES (REX) 1 PY344 2 PY102–PY103 REPUBLIC FINANCIAL CORPORATION (RFC) 1 PA011 PG199 PG225 PG433 PG502–PG503 PG622 PG704 REPUBLIC OF INDONESIA (IDO) 2 PL601–PL602 3 PL603 REPUBLIC OF KOREA AIR FORCE (KAF) 5 PP221 REPUBLIC OF NIGER (NIR) 2 PY166 REPUBLIC OF VENEZUELA (VNZ) 2 PK070 REPUBLICAIR (RPB) 2 PL553 PL555 RICO (RLA) 2 PK119–PK120 ROYAL AIR MAROC (RAM) 2 PK271–PK272 PY671 3 PY672 5 PT581–PT584 6 PT585–PT586 ROYAL THAI AIR FORCE (TAF) 3 PK519 8 PV296June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 44 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** RUTACA AIRLINES (ZRU) 2 PK281 PK611 PK613 RYAN INTERNATIONAL AIRLINES (RYN) 2 PK097 PK543 PK602 PK606 PK608 PN106 RYANAIR (RYR) 2 PK503 RYM AIRLINES (RYM) 2 PL017–PL019 SAFAIR (SFA) 1 PY002 2 PK733 PK743 PK746 PK771 PL110 SAMCO AVIATION (SMO) 2 PL581 SAS BRAATHENS (BRT) 10 PT022 11 PW573 5 PT002–PT004 PT006–PT008 PT011–PT012 PT024–PT025 6 PT013–PT015 7 PW574 PW576 8 PV351 SAT AIRLINES (SKH) 2 PL221 SAUDI ARABIAN AIRLINES (SVA) 1 PL727–PL728 PY036 2 PK312 PK316–PK317 PL729–PL733 PL735 SEB MANAGEMENT CORPORATION (YNS) 5 PT219 SHAHEEN INTERNATIONAL (SHK) 2 PL003 PL551 PL561 SHANDONG AIRLINES (SHG) 5 PM413–PM414 6 PQ391–PQ395 PR007–PR009 PR013–PR014 PR161 9 PR006 SHANTOU AIRLINES (SHT) 5 PM415–PM417 SHEIKH MUSTAFA EDREES (SME) 2 PL505June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 45 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** SHENZHEN AIRLINES (SHZ) 5 PQ486 PS691–PS692 PS851–PS852 6 PQ972 PQ976 PQ995 PS629 SIBERIA AIRLINES (SBR) 5 PT381 PT388–PT389 PT396 PT401 PT420–PT421 PT430–PT431 PT433 SIERRA PACIFIC AIRLINES (SRP) 2 PK627 PL621 SILVER AIR (SARI) (SVT) 1 PL726 2 PK313–PK314 PL734 SKY AIRLINES (SYC) 7 PV235 PW001 PW278 PW281 PW293 SKY KING (SKN) 1 PG059 2 PK351–PK353 PK696 PL002 PL006 SKY SERVICE (SSV) 1 PL736 PL740 2 PK628–PK629 PK881 PK884 PK971 PK973 4 PK526–PK527 SKYEUROPE (SKP) 5 PT050–PT051 PT054 PT056–PT057 PT147–PT148 6 PR162–PR166 SKYNET ASIA AIRWAYS (SNU) 7 PM555 8 PW274 PW855–PW856 SLOK AIR (SRO) 2 PM108–PM113 SLOVAK AIRLINES (SLV) 5 PP851 PP903 SOUTH AFRICAN AIRWAYS (SAA) 2 PK774 PK776 PL102 PL104–PL109 PL112–PL113 SOUTHERN AIRCRAFT SERVICES (HUZ) 2 PL471 SOUTHERN WINDS (SOW) 2 PJ005 PK029 PK047 PK116 PK146 PK253 PK616June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 46 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** SOUTHWEST AIRLINES (SWA) 5 PP101–PP169 PP188 PP190–PP193 PP202–PP205 PP301–PP304 PP351 PP353 PP376–PP382 PP402–PP403 PP501–PP502 PP727 PP731 PP803–PP804 PP821–PP824 PP827 PS751–PS778 PU001–PU025 6 PS779–PS799 PS901–PS941 SPACE WORLD AIRLINE/SWA (WIN) 2 PL021–PL022 SRIWIJAYA AIR (SJA) 2 PK304 PN023 PN026–PN027 4 PL746 PM254 STA SUPPLIES PTE. LTD. (SSP) 5 PQ040–PQ041 STAR AIR (SRH) 2 PK777 PL744 4 PN040 PN042–PN043 STAR UP S.A. (SRU) 2 PY101 STERLING EUROPEAN AIRLINES (STR) 5 PT121 PT125 6 PT127 PT132–PT134 SUNDOWNER OKLAHOMA CITY LLC (SDO) 5 PP514 PS653 7 PW313 PW316 TAAG (ANGOLA AIRLINES) (ANG) 2 PK661 PK664 PY162 4 PK665–PK666 TACA INTERNATIONAL AIRLINES (TAC) 1 PL737 TAF AEREAS LINHAS (TFL) 1 PY323 PY342 2 PK118 TANS (TAX) 2 PK113 PL101 PL103 PN082 TAROM - ROMANIAN AIR TRANSPORT (TRM) 5 PQ931–PQ934 6 PQ935 TEEBAH AIRLINES (EBH) 2 PN028June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 47 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** THAI AIRWAYS INTERNATIONAL (TII) 7 PW161–PW162 PW164–PW167 PW594 8 PW168–PW171 THE PEGASUS AVIATION COMPANY (PEG) 2 PK285 THOMSONFLY (BRI) 5 PT123–PT124 PT181–PT182 6 PQ436–PQ437 PR011 PR024 9 PR023 TITAN AIRWAYS (TIU) 5 PM387 PP505 PS620 TNT AIRWAYS (TNB) 5 PP384 PP391 PP414 PP416 PP702 PP711 TRANS AIR CONGO (TSC) 2 PY243 TRANSAERO AIRLINES (TRX) 2 PK451–PK452 PK773 PK779 5 PP963 PP966 7 PW024 PW040 PW113 PW120 TRANSMILE AIR SERVICES (TML) 1 PY381 2 PY151 4 PN472 PN474 TRAVEL SERVICE (TSF) 5 PT432 PT436 7 PW006 TRITON AVIATION SERVICES (TIA) 1 PJ101 PJ103 2 PK674 PK677–PK678 PL408 PL411 PL770 PN101 TUI AIRLINES BELGIUM (TLB) 7 PW511 PW513 8 PW522 TUNISAIR (TUN) 2 PK861–PK863 PY621 5 PT641–PT643 6 PT644June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 48 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** TURKISH AIRLINES (THY) 7 PM552–PM553 PM557 PM559–PM560 PM562–PM564 PW012 PW018–PW019 PW045 PW049–PW050 PW287 8 PW290–PW291 TURKMENISTAN AIRLINES (TUE) 5 PQ265 PQ801–PQ802 UKRAINE INTERNATIONAL AIRLINES (UKR) 5 PQ251 PT055 PT059 6 PQ991 PR042 PR181 7 PM551 PW701–PW702 UNICAPITAL AIR GROUP (UAG) 2 PK695 UNITED AIRLINES (UAL) 1 PG024 PG052 PG054–PG055 PG057 PG067 PG069–PG071 2 PL004–PL005 PL009 PL012 PL014–PL016 PL020 5 PQ101–PQ115 PQ118 PQ120–PQ122 PQ125–PQ143 PQ146–PQ151 PQ164–PQ167 PQ169–PQ183 PQ185–PQ186 PQ198–PQ199 PQ201–PQ202 PT382–PT387 PT390–PT395 PT398–PT399 PT402–PT419 PT422–PT423 UNIVERSAL ASSET MANAGEMENT (UAM) 2 PM054 PM056–PM061 US AIR FORCE (USF) 2 PJ202 PJ206 PJ211 PJ213–PJ217 PJ219 US AIRWAYS (USA) 11 PV032 PV038 2 PK597 PK609 PM114 5 PP003–PP008 PP012 PP014–PP020 PP024–PP027 PP030–PP032 PP034–PP042 PP045–PP054 PP401 PP404–PP405 PP410 PP413 PP415 PP417–PP418 PP422–PP429 PP431–PP440 7 PV001–PV010 PV012–PV022 PV025–PV031 PV033–PV037 PV039–PV040 PV044–PV055 UT FINANCE CORPORATION (ZZJ) 5 PQ153June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 49 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** VARIG AIRLINES (VAR) 10 PQ331 2 PK111–PK112 PK114 PK144 PK211 5 PP839 PP905–PP906 PP917 PP921–PP922 PP927 PP981–PP982 PP987–PP990 PQ227 PQ256–PQ259 PQ266–PQ267 PQ290 PQ303 PS619 PT058 PT212–PT213 PT216–PT218 PT220 6 PR043–PR044 PR132 PS624 PS627 PS872 PT724–PT725 PT854 7 PV201–PV202 PW008 PW118 VASP AIRLINES (VSP) 1 PG472 2 PK581 VIRGIN EXPRESS AIRLINES (EBA) 5 PS656 6 PQ984 PQ989 PQ993 PS972 7 PW013 PW571–PW572 8 PW271 PW275 VIRGIN NIGERIA (VNA) 6 PQ982 VISION AIR (VEG) 6 PS626 WEBJET LINHAS AEREAS LTDA. (WJL) 5 PP679 PS603 WELLS FARGO (FSB) 1 PL741 2 PJ110–PJ111 WESTAIR CARGO AIRLINES (WCO) 1 PY037 WESTJET (WJI) 2 PJ108 PJ113 PK241 PK713–PK714 PK716 PL171 4 PK565 XIAMEN AIRLINES (XIA) 5 PQ295–PQ296 PQ471 PQ493 PT026–PT029 6 PT030–PT031June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 50 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
IDENTIFICATION BY VARIABLE NUMBER **Variable Group** PA001–PA022 1 PA099 1 PA231–PA232 1 PC001–PC005 1 PG001–PG075 1 PG199 1 PG201–PG230 1 PG251–PG255 1 PG271–PG279 1 PG301–PG314 1 PG331–PG332 1 PG351–PG356 1 PG375 1 PG401–PG403 1 PG431–PG442 1 PG471–PG475 1 PG501–PG505 1 PG571–PG586 1 PG621–PG630 1 PG651–PG652 1 PG701–PG705 1 PH001 2 PH011–PH013 2 PH021–PH024 2 PH701–PH715 1 PH731–PH732 1 PH741–PH742 1 PH743 2 PJ001–PJ002 1 PJ003–PJ009 2 PJ031–PJ032 1 PJ071–PJ072 1 PJ101–PJ104 1 PJ105–PJ119 2 PJ201–PJ219 2 PJ301–PJ302 7 PJ551–PJ556 7June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 51 of 198 PJ557–PJ561 8 PJ601–PJ615 8 PJ811 8 PJ816–PJ817 8 PK026–PK029 2 PK041–PK053 2 PK061–PK070 2 PK081–PK082 2 PK091–PK099 2 PK101–PK103 2 PK111–PK120 2 PK141–PK146 2 PK201–PK204 2 PK211–PK215 2 PK216–PK220 4 PK221–PK223 2 PK231–PK241 2 PK251–PK258 2 PK271–PK274 2 PK281–PK289 2 PK291 2 PK301–PK318 2 PK341 2 PK351–PK361 2 PK391 2 PK431–PK433 2 PK451–PK452 2 PK461–PK469 2 PK495 2 PK501–PK504 2 PK511–PK514 2 PK515 4 PK519 3 PK521–PK525 2 PK526–PK528 4 PK541–PK564 2 PK565 4 PK581 2 PK591–PK599 2 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 52 of 198 PK601–PK617 2 PK621–PK637 2 PK641–PK642 2 PK661–PK664 2 PK665–PK666 4 PK671–PK680 2 PK681 4 PK691–PK697 2 PK711–PK716 2 PK731–PK749 2 PK750–PK765 4 PK771–PK779 2 PK801–PK804 2 PK819–PK827 2 PK830 2 PK861–PK863 2 PK871–PK874 2 PK881–PK884 2 PK901–PK932 2 PK933–PK938 4 PK971–PK974 2 PL001–PL028 2 PL061 2 PL081 2 PL101–PL113 2 PL151 2 PL171–PL172 2 PL201–PL203 2 PL221 2 PL401–PL417 2 PL421 2 PL441 2 PL451–PL454 2 PL455–PL456 4 PL471 2 PL491 2 PL501–PL506 2 PL551–PL562 2 PL581 2 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 53 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PL601–PL602 2 PL603 3 PL611 2 PL621–PL623 2 PL624–PL626 4 PL631–PL632 2 PL711–PL712 1 PL716 1 PL717–PL725 2 PL726–PL728 1 PL729–PL735 2 PL736–PL742 1 PL743–PL745 2 PL746–PL747 4 PL756 1 PL758 2 PL761 1 PL762–PL770 2 PL781–PL788 2 PL793 2 PL801–PL803 1 PM001–PM006 2 PM016–PM017 3 PM021–PM023 2 PM051–PM062 2 PM063–PM066 4 PM101–PM117 2 PM118–PM119 3 PM141–PM142 2 PM171 4 PM181 4 PM251–PM255 4 PM281–PM283 4 PM381–PM390 5 PM391 10 PM392–PM399 5 PM401–PM417 5 PM541–PM550 5 PM551–PM564 7 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 54 of 198 PN001–PN002 2 PN021–PN028 2 PN029–PN038 3 PN039–PN043 4 PN081–PN083 2 PN084–PN086 3 PN101–PN112 2 PN113–PN117 4 PN131–PN135 3 PN136–PN163 4 PN401–PN420 4 PN431–PN433 4 PN451–PN456 4 PN471–PN474 4 PN481 4 PN491–PN493 4 PN501–PN502 4 PN511–PN512 4 PN521 4 PP001–PP054 5 PP101–PP169 5 PP181–PP199 5 PP201–PP205 5 PP221 5 PP231–PP243 5 PP281–PP286 5 PP301–PP305 5 PP351–PP353 5 PP376–PP384 5 PP391–PP393 5 PP401–PP440 5 PP471–PP475 5 PP501–PP519 5 PP520 6 PP521–PP522 5 PP631–PP634 5 PP651–PP652 5 PP671–PP699 5 PP701–PP733 5 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 55 of 198 PP771–PP779 5 PP801–PP806 5 PP807 10 PP808 5 PP821–PP827 5 PP831–PP848 5 PP851–PP852 5 PP861–PP875 5 PP876–PP877 6 PP891–PP899 5 PP901–PP936 5 PP946–PP948 5 PP951–PP952 5 PP961–PP967 5 PP981–PP991 5 PP993 5 PQ001–PQ016 5 PQ026–PQ041 5 PQ051–PQ092 5 PQ101–PQ188 5 PQ189 10 PQ190 5 PQ191 10 PQ192–PQ199 5 PQ201–PQ202 5 PQ221–PQ237 5 PQ241–PQ243 5 PQ251–PQ267 5 PQ281–PQ299 5 PQ301–PQ303 5 PQ304 10 PQ305–PQ307 5 PQ331 10 PQ332 5 PQ341–PQ344 5 PQ345–PQ348 6 PQ361–PQ371 5 PQ372–PQ373 6 PQ391–PQ395 6 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 56 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PQ401–PQ413 5 PQ414–PQ415 6 PQ416 8 PQ417–PQ418 6 PQ421 5 PQ431 5 PQ432–PQ438 6 PQ447–PQ448 6 PQ451 6 PQ454 6 PQ471–PQ474 5 PQ475 6 PQ479–PQ481 5 PQ486–PQ487 5 PQ491–PQ493 5 PQ771–PQ772 5 PQ791–PQ793 5 PQ801–PQ805 5 PQ931–PQ934 5 PQ935 6 PQ951 6 PQ971–PQ997 6 PR001–PR005 6 PR006 9 PR007–PR017 6 PR021–PR022 6 PR023 9 PR024–PR034 6 PR041–PR045 6 PR061–PR072 6 PR077–PR082 6 PR091–PR092 6 PR096 6 PR101 6 PR121–PR122 6 PR131–PR132 6 PR141–PR143 6 PR161–PR172 6 PR181 6 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 57 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PS601–PS620 5 PS621–PS630 6 PS631 5 PS636–PS638 5 PS641–PS644 5 PS651–PS657 5 PS666–PS669 5 PS691–PS692 5 PS701–PS703 5 PS704–PS706 6 PS751–PS778 5 PS779–PS799 6 PS811 6 PS836–PS837 5 PS841–PS844 5 PS845–PS846 6 PS851–PS852 5 PS856 5 PS861–PS863 6 PS866–PS868 6 PS871–PS874 6 PS896–PS897 6 PS901–PS941 6 PS956–PS957 6 PS961–PS963 6 PS971–PS978 6 PT001–PT012 5 PT013–PT015 6 PT021 5 PT022 10 PT023–PT029 5 PT030–PT031 6 PT041–PT064 5 PT101 10 PT102–PT105 5 PT121–PT125 5 PT126–PT138 6 PT146–PT148 5 PT161–PT170 5 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 58 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PT181–PT188 5 PT211 10 PT212–PT220 5 PT295 10 PT301–PT309 5 PT331–PT360 5 PT381–PT399 5 PT401–PT438 5 PT501–PT514 5 PT515–PT517 6 PT561–PT565 5 PT581–PT584 5 PT585–PT586 6 PT611–PT621 5 PT641–PT643 5 PT644 6 PT651–PT656 5 PT671–PT672 5 PT681–PT682 6 PT683 9 PT684–PT685 6 PT701–PT703 5 PT716–PT717 6 PT721–PT725 6 PT801–PT818 5 PT819–PT825 6 PT826–PT828 5 PT829–PT834 6 PT851 5 PT852–PT854 6 PT871–PT886 6 PT901–PT930 6 PT971–PT973 6 PT981–PT985 6 PT996 6 PU001–PU025 5 PU301 6 PU311–PU313 6 PV001–PV031 7 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 59 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PV032 11 PV033–PV037 7 PV038 11 PV039–PV055 7 PV201–PV203 7 PV204–PV209 8 PV226–PV229 8 PV231–PV237 7 PV271–PV272 7 PV281–PV284 7 PV285–PV287 8 PV296 8 PV301–PV302 8 PV351 8 PV356–PV357 8 PW001–PW029 7 PW030 11 PW031–PW054 7 PW061–PW062 7 PW063 11 PW064–PW068 7 PW072 7 PW086–PW088 8 PW091–PW094 7 PW101–PW102 7 PW106 7 PW111–PW120 7 PW156–PW157 7 PW161–PW167 7 PW168–PW171 8 PW201–PW249 7 PW250–PW252 8 PW261–PW262 7 PW263–PW264 8 PW265–PW268 7 PW271–PW276 8 PW278 7 PW281–PW288 7 PW289–PW292 8 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 60 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PW293 7 PW296 7 PW301–PW327 7 PW401 7 PW402–PW408 8 PW411–PW418 8 PW421–PW424 8 PW431–PW435 8 PW441–PW450 8 PW461–PW467 7 PW501–PW502 7 PW503 11 PW504 7 PW511–PW517 7 PW518 11 PW519–PW520 7 PW521–PW522 8 PW524–PW525 8 PW526–PW527 7 PW528–PW530 8 PW531–PW547 7 PW548–PW550 8 PW556–PW557 7 PW561–PW562 7 PW563 11 PW564 7 PW571–PW572 7 PW573 11 PW574–PW576 7 PW591–PW596 7 PW611–PW622 7 PW631 7 PW632 11 PW633–PW636 7 PW637 8 PW661–PW662 7 PW681–PW683 7 PW701–PW702 7 PW711–PW717 7 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 61 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

PW741–PW742 7 PW761 7 PW771 7 PW831 8 PW851–PW856 8 PX071 1 PX701 1 PY001–PY008 1 PY021 1 PY022 2 PY031 1 PY036–PY037 1 PY046–PY047 1 PY048 2 PY051–PY053 2 PY056–PY057 3 PY101–PY103 2 PY111–PY113 2 PY131–PY135 2 PY141–PY143 2 PY151–PY154 2 PY156–PY157 2 PY161–PY162 2 PY166 2 PY191 2 PY201 2 PY221–PY222 2 PY231 2 PY241–PY244 2 PY270–PY275 2 PY281 2 PY286 2 PY301–PY304 1 PY321–PY323 1 PY341–PY346 1 PY361–PY362 1 PY381 1 PY401 2 PY409–PY410 4 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 62 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2. Spares Affected
None. **B. Concurrent Requirements**
None.
**C. Reason** The changes shown in this service bulletin will decrease the probability of cracks in the frame at STA 727 where Stringer (S)-18A is attached. This area is a primary structural element. Operation with cracks in the frame will decrease the structural integrity of this area. Unscheduled downtime can be necessary to replace a frame that has a crack. Cracks in the S-18A chord are not a safety concern. Several operators have reported numerous cracks on multiple airplanes in the STA 727 frame outboard chord, where the S-18A outboard chord is attached. The cracks ranged from 0.016 inches, to a severed chord. Cracks initiate common to the 3 fastener holes or close vicinity to the fastener holes and on the forward edge of the frame outboard chords. For the fastener holes susceptible to cracking, several elongated holes were also found. Airplanes have accumulated between 20,000 - 85,000 flight-cycles and 27,000 - 74,000 flight hours. Previous revisions of this service bulletin inspected for cracks on airplanes with 7075-T6 frame outboard chords (Line Number 1-999) only. Since the release of Rev 1, seven operators have reported cracks in 7075-T73 chords with 20,000 - 52,000 flight-cycles. As a result of these new findings, this revision of the service bulletin expands the effectivity to include airplanes with 7075-T73 frame outboard chords. The cracks were caused by fatigue; for line number 1-999 airplanes (7075-T6 frame outboard chord), fretting of adjacent parts contributed to the initiation of the fatigue damage. Three operators have reported four cracks in the radius of the 65-46547-9 Auxiliary Chord on three airplanes. 1.00 inch cracks were reported. Airplanes have accumulated between 46,000 - 85,000 flight-cycles and 41,000 - 64,000 flight hours. PY411 2 PY421–PY422 2 PY441 2 PY451 2 PY461–PY462 2 PY463 4 PY591–PY595 4 PY611–PY612 2 PY621 2 PY631 2 PY651 2 PY671 2 PY672 3 PY721 4 PY741 2 **Variable Group**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 63 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

Several operators have reported numerous cracks on multiple aircraft in the S-18A outboard chord common to the fastener locations just aft of STA 727. Airplanes have accumulated between 30,000 - 76,000 flight-cycles and 32,000 - 65,000 flight hours. One operator found one crack on one airplane in the S-18A chord, forward of STA 727 in the lower fastener row. The aircraft had 68,000 flight-cycles and 71,000 flight hours. Cracks have been found in S-18A chord sections at STA 727 of a thickness of 0.33 inches or less. The cracks were caused by fatigue. Four operators have reported four cracks on three aircraft with a "T" profile S-18A outboard chord. The vertical flange of the chord has cracked at the base, at the vertical flange run-out, near STA 727. These cracks can grow along the base of the vertical flange in the radius. These cracks have been associated with S-18A outboard chord installation pre-loads. Boeing Service Related Problem (SRP) 737-SRP-53-0162 is related to this service bulletin. Boeing Supplemental Structural Inspection Document D6-37089, Section 8.2, SSI Number F.29, is related to this service bulletin. Boeing Structural Item Interim Advisory (SIIA) 737-131 is related to this service bulletin. Boeing Structural Item Interim Advisory (SIIA) 737-44, 737-60, 737-74, 737-194, 737-274 impact the area of this bulletin but are not related. Federal Aviation Administration (FAA) Airworthiness Directive AD 95-12-17, is related to this service bulletin. The FAA is considering additional rule making that will make the compliance tasks and times given in Revision 2 of this Service Bulletin mandatory. Revision 1 was sent to add a S-18A outer chord repair. In addition, instructions were added, to trim the "Time Limited Repair" parts, to eliminate interference with fasteners. Revision 2 is sent to revise inspections, repairs, modifications and parts fabrication and to expand the airplane effectivity to cover all 737-100/200/300/400/500 series airplanes. Additional inspections are added to address new cracks found in the STA 727 outboard chord frame, STA 727 frame auxiliary chord and the stringer S-18A outboard chord. Instructions are added to modify the STA 727 frame time-limited repair into a permanent repair. Instructions are added to install a preventive modification for the S-18A outboard chord. Changes to this revision include: — Planning Information - The service history information relating to the new cracks is updated. All references are updated to reflect the inclusion of 737-300/400/500 series airplanes into the effectivity. — Material Information - New top kits are added to this service bulletin revision. — Accomplishment Instructions - Instructions are added to do new inspections, repairs and modifications. — Figures 1, 2, 3, 4, 5 and 6 are deleted. — Figures 7, 8, 9, 10, 11, 12, 13, 14, 16, 21, 22 and 24 are added to show new inspections. — Figure 15 is added to show access for the Time-limited repair. — Figure 17 is added to show the fabrication of parts for the Time-limited repair. — Figure 18 is added to show the installation of the Time-limited repair. — Figure 19 is added to show the removal of the Time-limited repair. — Figures 20 is added to show fabrication of the Time-limited repair replacement parts. — Figures 23 is added to show installation of the Shear Beam Repair. — Appendix A is revised to show the new compliance data.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 64 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

As part of a service bulletin validation program, the inspection, frame chord replacement, and preventive modification was completed on airplane PG576 before the initial release of this bulletin. **D. Description** The airplane effectivity is divided in 11 groups because of differences in airplane configuration. Do the inspections that follow at the times given in the Compliance section. Do an external (wheel well) ultrasonic inspection of the STA 727 frame outboard chord at S-18A. Do an external (wheel well) HFEC inspection of the STA 727 frame outboard chord at S-18A. Do a detailed inspection for loose fasteners common to the four holes of the STA 727 frame outboard chord, forward flange at S-18A. Do an open hole eddy current inspection for cracks and a detailed inspection for hole elongation in stringer S-18A. Do these inspections as shown in PART 1 of the Accomplishment Instructions at the times given in the Compliance section. As part of the accomplishment of this Service Bulletin, a frame chord replacement may be required. Boeing Service Bulletin 737-53-1088 Revision 1, dated May 25, 2006 in conjunction with this service bulletin provides instructions on the STA 727 frame outboard chord replacement. Boeing Service Bulletin 737-53-1088 Revision 1, dated May 25, 2006 replaces the STA 727 frame outboard chord in two parts, an upper and lower outboard chord segment. Only the upper STA 727 frame outboard chord segment replacement is required to satisfy the requirements of this service bulletin.
**NOTE:** Boeing recommends that the STA 727 frame outboard chord preventive modification be installed with the replaced STA 727 frame outboard chord. Operators may install the STA 727 frame outboard chord modification at a later time, however inspections may be required and increased installation costs will be incurred. Boeing also recommends replacing both chord segments at the same time. Replacing both chord segments at the same time will reduce inspection requirements and task hours required to perform the STA 727 frame outboard chord replacement. If cracks are found in the STA 727 frame outboard chord, replace the frame outboard chord and optionally add the preventive modification, or install the time-limited frame chord repair as shown in this service bulletin before any more flights or ask Boeing for repair data. If the preventive modification is installed on a new or crack free existing STA 727 frame outboard chord where the final edge margins are equal to or greater than 1.7D, then the modification is permanent and inspection requirements are terminated. If the preventive modification is installed on a new or crack free existing STA 727 frame outboard chord where the final edge margins are equal to or greater than 1.5D but less than 1.7D, then do a one-time HFEC hole inspection as shown in PART 8 of the Accomplishment Instructions at the times given in the Compliance section. If a new or crack free existing STA 727 frame outboard chord is installed without the preventive modification then perform inspections as shown in PART 1 of the Accomplishment Instructions at the times given in the Compliance section. As an option to the STA 727 frame outboard chord replacement, a time-limited repair can be fabricated and installed. A time-limited repair can be used to repair cracks that extend from the forward edge of the STA 727 frame outboard chord, or from the forward fastener hole, but do not extend past the second fastener hole aft on the forward flange. The time-limited repair angle replaces the forward splice angle of the STA 727 frame outboard chord if a chord replacement kit has been previously installed per Boeing Service Bulletin 737-53-1088.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 65 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

**NOTE:** The time-limited repair is intended to provide an option if a replacement chord is not available in a timely manner. Boeing recommends that a replacement chord be used whenever possible. The time-limited repair will result in additional work and future chord replacement. Within 4500 flight cycles after the time-limited repair was installed, remove the repair and perform a STA 727 frame outboard chord replacement using additional instructions provided in the accomplishment instructions and optionally add the preventive modification as previously described, including an evaluation of the chord’s condition. If no cracks are found in the STA 727 frame outboard chord, then continue inspections as shown in the accomplishment instructions or optionally add the preventive modification as shown in this service bulletin.
**NOTE:** Boeing recommends that the stringer S-18A outboard chord preventive modification be installed when the STA 727 frame outboard chord preventive modification is installed. To convert a modification with inspection requirements to a permanent modification, ask Boeing for repair instructions.
**NOTE:** This conversion will likely use a STA 727 frame outboard chord replacement with the installation of a modification strap. Do an internal (cargo hold) detailed and eddy current inspection of the STA 727 frame auxiliary chord for cracks in the radius, between stringer S-17 and S-23 (end of chord) per PART 1 of the Accomplishment Instructions at times given in the compliance section. If cracks are found, repair before further flight. Contact Boeing for repair data.
**NOTE:** A local repair will be provided to address the STA 727 frame auxiliary chord cracks. Report airplane flight-cycles, crack length, location and growth direction to Boeing for any size cracks in the STA 727 frame auxiliary chord. Provide photographs if possible. If no cracks are found, and a permanent frame chord modification has not been installed, continue inspections as shown in PART 1 of the Accomplishment Instructions at times given in the Compliance section. If no cracks are found, repeat auxiliary chord inspections until the frame chord is replaced with 7075-T73 and modified per PART 6 of the Accomplishment Instructions. Do an external detailed inspection of the S-18A outboard chord at STA 727 for cracks. Do an external surface HFEC inspection of the S-18A outboard chord at STA 727 for cracks. Do a surface eddy current inspection on airplanes that have a "T" profile on the stringer outboard chord. Inspect the run-out of the vertical flange across the run-out face and the radii on both sides of the flange from the run-out to two inches forward. Perform these inspections per PART 2 of the Accomplishment Instructions at times given in the Compliance section. If cracks are found in the S-18A outboard chord, install the S-18A outboard chord permanent repair as shown in this service bulletin before further flight or ask Boeing for repair instructions. Inspection requirements for S-18A outboard chord are terminated once the S-18A chord is repaired.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 66 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

If no cracks are found, continue inspections as shown in PART 2 Accomplishment Instructions. Optionally install the S-18A outboard chord preventive modification. The S-18A outboard chord preventive modification is permanent and inspection requirements for the S-18A outboard chord are terminated.
**NOTE:** Boeing recommends that the S-18A outboard chord preventive modification be installed when the STA 727 frame outboard chord preventive modification is installed. More work is necessary for operators that have replaced the chord as shown in the initial release of Service Bulletin 737-53-1088. Refer to Paragraph 1.E., Compliance of this service bulletin. Airplanes modified or repaired per a previous issue require additional inspections.
**NOTE:** 1. The changes given in Boeing Service Bulletin 737-53A1039, "Fuselage - Skin Lap Joint Inspection and Repair" can be made on applicable airplanes before or during the changes given in this service bulletin. 2. The changes given in Boeing Service Bulletin 737-53-1066, "Fuselage - Stringer 18A Shear Beam Inspection, Repair and Modification", can be made on applicable airplanes before or during the changes given in this service bulletin. 3. The changes given in Boeing Service Bulletin 737-53-1076, "Fuselage - Circumferential Butt Splices and Bonded Doublers Inspection, Repair and Modification", can be made on applicable airplanes before or during the changes given in this service bulletin. 4. The changes given in Boeing Service Bulletin 737-53-1077, "Fuselage - Skin Inspection, Repair, and Modification Aft of Body Station 727 Between Stringer S-18 and S-21", can be made on applicable airplanes before or during the changes given in this service bulletin. 5. The changes given in Boeing Service Bulletin 737-53-1089, "Fuselage - Skin Cracks at Stringer 17 Inspection and Preventive Modification", can be made on applicable airplanes before or during the changes given in this service bulletin. 6. The changes given in Boeing Service Bulletin 737-53-1124, "Fuselage - Bonded Doublers (Tear Straps) - Inspection and Repair - For Delamination above Stringer 26 Between Stations 259 and 1016", can be made on applicable airplanes before or during the changes given in this service bulletin. PLEASE SEND A REPORT OF YOUR INSPECTION PROGRAM. ALSO, SEND THE INSPECTION RESULTS WHEN EACH INSPECTION IS COMPLETE. REFER TO THE FLIGHT SAFETY SECTION IN THE ADDENDUM.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 67 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT E. Compliance**  This bulletin has a Flight Safety Inspection Program that is the minimum necessary to keep the structural integrity of the STA 727 frame outboard chord. Table 1 inspection of the S-18A outboard chord is recommended as an economic inspection to find cracks prior to causing extensive damage needing a costly repair. Table 2 through 5 inspections of the STA 727 frame and auxiliary chord are required inspections to maintain safety of flight. Group 1-6, 9 and 10: Table 1 - Inspection for cracks in S-18A Outboard Chord with a thickness of 0.33 inches or less (Recommended Economic Inspection)

**Condition Action Threshold (which ever occurs**  **later) Repeat Interval**  **(Not to Exceed Flight Cycles)**  **Terminating action for** 

**Repeat Inspection**  **Total Airplane Flight Cycles**  **Airplane Flight Cycles**  No previous inspections Detailed Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 2 - Economic Inspection Program 27,000 5,000 after the date of this Service Bulletin Revision 2 5,000 Repair or modification of the S-18A Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 5 - S-18A Outboard Chord Repair or Paragraph 3.B., PART 7 - S-18A Outboard Chord Preventive Modification Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 2 - Economic Inspection Program 42,000 20,000 after the date of this Service Bulletin Revision 2 15,000

Inspected as given in a previous release of this Service Bulletin Detailed Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 2 - Economic Inspection Program - At next repeat interval as given in this service bulletin, Revision 1 or original issue, or within 5,000 after Revision 2 release, whichever is sooner. 5,000 Repair or modification of the S-18A Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 5 - S-18A Outboard Chord Repair or Paragraph 3.B., PART 7 - S-18A Outboard Chord Preventive Modification Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 2 - Economic Inspection Program - At next repeat interval as given in this service bulletin, Revision 1 or original issue, or within 20,000 after Revision 2 release, whichever is sooner. 15,000June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 68 of 198 Groups 1-11 Configuration 4: Table 2 - Inspection for cracks in STA 727 Frame Outboard Chord for airplanes with original production frame chord and without the STA 727 Frame Modification Installed (Required minimum for safety)

**Condition Action Threshold (which ever occurs**  **later) Repeat Interval**  **(Not to Exceed Flight Cycles)**  **Terminating action for** 

**Repeat Inspection**  **Total Airplane Flight Cycles**  **Airplane Flight Cycles**  No previous inspections Ultrasonic and surface HFEC Inspections as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program 27,000 5,000 after the date of this Service Bulletin Revision 2 5,000 Modification of the STA 727 Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 6 - STA 727 Frame Outboard Chord Preventive Modification Open hole Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program 27,000 10,000 after the date of this Service Bulletin Revision 2 15,000

Inspected as given in a previous release of this Service Bulletin Ultrasonic and surface HFEC Inspections as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program - At next repeat interval as given in this service bulletin, Revision 1 or original issue, or within 5,000 after Revision 2 release, whichever is sooner. 5,000 Modification of the STA 727 Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 6 - STA 727 Frame Outboard Chord Preventive Modification Open hole Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program - At next repeat interval as given in this service bulletin, Revision 1 or original issue, or within 10,000 after Revision 2 release, whichever is sooner. 15,000June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 69 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** Groups 1-11 Configuration 1: Table 3 - Inspection for cracks in the STA 727 Frame Outboard Chord for airplanes with the Outboard Chord replaced without the Modification of the STA 727 Frame Outboard Chord accomplished. (Required minimum for safety)

**Condition Action Threshold (which ever occurs**  **later)**
**Repeat Interval (Not to Exceed**  **Flight Cycles) Terminating**  **action for Repeat Inspection**  **Total Airplane Flight Cycles**  **After Chord Replacement**  **Airplane Flight Cycles** 

No previous inspections Ultrasonic, LFEC and edge HFEC Inspections as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program 27,000 5,000 after the date of this Service Bulletin Revision 2 5,000 Modification of the STA 727 Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 6 - STA 727 Frame Outboard Chord Preventive Modification Open hole Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program 27,000 10,000 after the date of this Service Bulletin Revision 2 15,000

Inspected as given in a previous release of this Service Bulletin Ultrasonic, LFEC and edge HFEC Inspections as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program - At next repeat interval as given in this service bulletin, Revision 1 or original issue, or within 5,000 after Revision 2 release, whichever is sooner. 5,000 Modification of the STA 727 Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 6 - STA 727 Frame Outboard Chord Preventive Modification
Open hole Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program - At next repeat interval as given in this service bulletin, Revision 1 or original issue, or within 10,000 after Revision 2 release, whichever is sooner. 15,000June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 70 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** Table 4 - "One-Time" Follow On Inspection for cracks in STA 727 Frame Outboard Chord at S-18A for airplanes with the Outboard Chord Interim modification accomplished (Edge Margin less than 1.7D but equal to or greater than 1.5). (Required minimum for Safety).

**Condition Action Threshold** 

**Repeat Interval (Not to Exceed**  **Flight Cycles) Lowest Airplane**  **Flight Cycles after the STA 727 frame** 

**outboard chord modification was** 

**accomplished Highest Airplane**  **Flight Cycles after the STA 727 frame** 

**outboard chord modification was** 

**accomplished** Each location where the fastener edge margin in the STA 727 Frame Outboard Chord forward flange is equal to or greater than 1.5D and less than 1.7D Open Hole Eddy Current as shown in Accomplishment Instructions, Paragraph 3.B., PART 8 - One Time Inspection of STA 727 Frame Outboard Chord Interim Modification. 50,000 60,000 None

Groups 1-3, Configurations 1, 3 and 4; Group 4-11, Configurations 1 and 4: Table 5 - Inspection for cracks in STA 727 Auxiliary Chord on Airplanes without the STA 727 outboard chord modification accomplished or with 7075-T6 Frames. (Required minimum for Safety)

**Action Threshold (whichever occurs later)** 
**Repeat Interval (Not to Exceed**  **Flight Cycles) Terminating action for**  **Repeat Inspection (a) Total**  **Airplane Flight Cycles**  **Airplane Flight Cycles after the**  **date of this Service Bulletin Revision 2**  Detailed Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program 27,000 5,000 15,000 Modification of the STA 727 Outboard Chord as shown in Accomplishment Instructions, Paragraph 3.B., PART 6 - STA 727 Frame Outboard Chord Preventive Modification and complete chord replacement as shown in Accomplishment Instructions Paragraph 3.B., Part 3 - STA 727 Frame Outboard Chord Repair. (b) Eddy Current Inspection as shown in Accomplishment Instructions, Paragraph 3.B., PART 1 - Flight Safety Inspection Program 27,000 5,000 15,000

(a) Groups 1-11, Configuration 1 - Airplane Flight Cycles After Frame Chord Replacement (b) Accomplishment of the terminating actions does not prevent cracks in the auxiliary chord but mitigates the safety concern related to the STA 727 frame outboard chord. Inspections of the auxiliary chord after completion of the terminating actions are optional.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 71 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

Federal Aviation Administration (FAA) Airworthiness Directive AD 95-12-17, is related to this service bulletin. The FAA is considering additional rule making that will make the compliance tasks and times given in Revision 2 of this Service Bulletin mandatory. **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. This service bulletin has been approved by the FAA. In addition, the Manager of the FAA Seattle Aircraft Certification Office approves the compliance and accomplishment instructions (i.e. compliance times, inspection or modification) defined in this service bulletin as an alternative method of compliance (AMOC) to the requirements of paragraph (a), (b), (c), (d), (e), (f) and (g) of AD 95-12-17. All provisions of AD 95-12-17 that are not specifically referenced in the above statement remain fully applicable and must be complied with. As part of this latest revision, inspections of the outboard chord of stringer S-18A are no longer required. The FAA is considering further rule making that would mandate the recommendations included in Revision 2 of this Service Bulletin. The compliance information provided in Appendix A, Table 1, of this service bulletin, Revision 2, are approved as an alternative method of compliance to paragraph (b) and (c) of Airworthiness Directive (AD) 98-11-04 R1 for the inspections of Structurally Significant Item F-29 of Supplemental Structural Inspection Document, D6-37089. This AMOC only applies to the areas inspected per this service bulletin, Revision 2, and to those airplanes identified in this service bulletin, Revision 2. All provisions of 98-11-04 R1 that are not specifically referenced in the above statements remain fully applicable and must be complied with. If operators choose this AMOC, then they must revise their FAA approved maintenance or inspection program with these alternative inspections. Table 6: STA 727 Frame Outboard Chord Time-Limited Repai r

**Condition Action Compliance Time**  **(Not to Exceed Flight Cycles from the Time of**  **Installation of the Repair)** STA 727 Frame Outboard Chord Time-Limited Repair installed Replace the Time-Limited Repair as shown in Accomplishment Instructions, Paragraph 3.B., Part 9 -Replacement of the TimeLimited Repair 4,500June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 72 of 198 **G. Manpower** The data below shows an estimate of the man-hours necessary to do the inspection, repair, and preventive modification for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator man-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 make the parts — Time to find the tools.

**PART 1 - Flight Safety Inspection Program**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 2 2 1 Figure 7 2 2.10 1.05 Figure 8 1 1 1 Figure 9 1 0.75 0.75 Figure 11 2 1.75 0.87 Figure 12 2 1.75 0.87 Figure 24 2 1.75 0.87 Close Access 2 2 1 TOTAL FOR EACH AIRPLANE 13.10 7.41 Group 1, 2, 3, 4, 5, 6, 9 and 10 **PART 2 - Economic Inspection Program**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 2 2 1 Figure 13 2 1.50 0.75 Figure 14 2 1.50 0.75 Close Access 2 2 1 TOTAL FOR EACH AIRPLANE 7 3.5
**PART 3 - STA 727 Frame Outboard Chord Repair**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 5 5 1 TOTAL FOR EACH AIRPLANE 5 1June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 73 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT PART 4 - STA 727 Frame Outboard Chord Time-Limited Repair** 

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 5 11.50 2.30 Inspection 2 1 0.50 Figure 15 2 8 4 Figure 16 1 1 1 Figure 17 (a) - - - Figure 18 4 30 7.50 Close Access 5 11.50 2.30 TOTAL FOR EACH AIRPLANE 63 17.60 (a) Time to make parts not included. Group 1, 2, 3, 4, 5, 6, and 9 **PART 5 - S-18A Outboard Chord Repair**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 5 11.50 2.30 Figure 21 4 26 6.50 Close Access 5 11.50 2.30 TOTAL FOR EACH AIRPLANE 49 11.10

**PART 6 - STA 727 Frame Outboard Chord Preventive Modification**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 5 11.50 2.30 Inspection 2 2 1 Figure 7 2 2.10 1.05 Figure 8 1 1 1 Figure 9 1 0.75 0.75 Figure 10 2 5 2.50 Figure 22 1 0.25 0.25 Close Access 5 11.50 2.30 TOTAL FOR EACH AIRPLANE 34.10 11.15 Group 1, 2, 3, 4, 5, 6, and 9 **PART 7 - S-18A Outboard Chord Preventive Modification**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 2 2 1 Close Access 2 2 1 TOTAL FOR EACH AIRPLANE 4 2June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 74 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

**H. Weight and Balance Changes**

**I. Electrical Load Data** Not applicable

**PART 8 - One-Time Inspection of the STA 727 Frame Outboard Chord Interim Modification** 

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 2 2 1 Figure 10 2 5 2.50 Close Access 2 2 1 TOTAL FOR EACH AIRPLANE 9 4.50
**PART 9 - Replacement of the Time-Limited Repair**

**Task Number of**  **Persons Task-Hours Elapsed Hours** Access 2 6.50 3.25 Figure 19 4 10 2 Figure 20 (a) - - - Figure 23 4 30 7.50 Close Access 2 6.50 3.25 TOTAL FOR EACH AIRPLANE 53 16 (a) Time to make parts not included.

**Task Change in Weight (Pounds)**  **Change in Moment (Pound-Inches)**  STA 727 Frame Preventive Modification Kit: 65C37277-1, -2, -3, -4, -5, -6, -7, -8. +8 +5,800
STA 727 Frame Time Limited Repair +6 +4,360 Time Limited Repair Modification (Shear Beam Repair) None None

S-18A Preventive Modification Kit: 65C38491-1, -2. +4 +2,900

STA 727 Frame and S-18A Preventive Modification Combination Kit: 65C37277-17, -18, -19, -20, -21, -22. +10 +7,270

STA 727 Frame and S-18A Preventive Modification Combination Kit: 65C37277-23, -24, -25, -26. +7.8 +5,670
S-18A Chord Repair: Repair Kit 65C37565-5, -6, -7, -8 +6.4 +4,650 S-18A Chord Repair: Repair Kit 65C38642-1, -2, -3, -4, -5, -6 +13.4 +9,740
S-18A Chord Repair: Repair Kit 65C38642-7, -8, -9, -10 +10 +7,270June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 75 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**J. References** 1. Existing Data: a. 737-100/200 Maintenance Manual (AMM) Subjects 25-52-51, 25-52-123, 25-52-131, 25-52-141, 26-21-11, 27-51-141, 27-51-261, 53-23-1, 53-51-21 b. 737-300/400/500 Maintenance Manual (AMM) Subject 25-52-51, 25-52-73, 25-52-81, 25-52-91, 26-21-11, 27-51-32, 27-51-67, 53-23-12, 53-51-21 c. 737-100/200 Structural Repair Manual (SRM) Subjects 51-10-6, 51-20-1, 51-50-1 d. 737-300 Structural Repair Manual (SRM) Subject 51-10-02, 51-30-01, 51-50-02 e. 737-400 Structural Repair Manual (SRM) Subject 51-10-02, 51-30-01, 51-50-02 f. 737-500 Structural Repair Manual (SRM) Subject 51-10-02, 51-30-01, 51-50-02 g. 737 Nondestructive Test (NDT) Manual D6-37239, Part 4, Subject 51-40-00, Figure 1 h. 737 Nondestructive Test (NDT) Manual D6-37239, Part 4, Subject 53-10-01 i. 737 Nondestructive Test (NDT) Manual D6-37239, Part 6, Subject 51-00-00, Figures 4, 16 and 23 j. 737 Nondestructive Test (NDT) Manual D6-37239, Part 6, Subject 53-30-00, Figure 5 k. Boeing Standard Overhaul Practices Manual (SOPM) Subject 20-41-02, 20-43-03 l. Service Related Problem (SRP) 737-SRP-53-0162 m. 737 Structural Item Interim Advisory (SIIA) 737-131, 737-44, 737-60, 737-74, 737-194, 737-274 n. 737 Supplemental Structural Inspection Document (SSID) D6-37089, Section 8.2, SSI Number F.29 o. Boeing Service Bulletin 737-53-1088, “Fuselage - Station Number 727 Bulkhead - Outboard Chord Inspection and Replacement” p. Boeing Service Bulletin 737-53A1039, "Fuselage - Skin Lap Joint Inspection and Repair" q. Boeing Service Bulletin 737-53-1066, "Fuselage - Stringer 18A Shear Beam Inspection, Repair and Modification" r. Boeing Service Bulletin 737-53-1076, "Fuselage - Circumferential Butt Splices and Bonded Doublers Inspection, Repair and Modification" s. Boeing Service Bulletin 737-53-1077, "Fuselage - Skin Inspection, Repair, and Modification Aft of Body Station 727 Between Stringer S-18 and S-21" t. Boeing Service Bulletin 737-53-1089, "Fuselage - Skin Cracks at Stringer 17 Inspection and Preventive Modification"June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 76 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** u. Boeing Service Bulletin 737-53-1124, "Fuselage - Bonded Doublers (Tear Straps) - Inspection and Repair - For Delamination above Stringer 26 Between Stations 259 and 1016" v. Boeing Service Bulletin 737-53-1170, "Fuselage - Stringer 18A Web at BS 727- Inspection, Repair and Preventive Change" w. Boeing Service Bulletin 737-53-1179, "Fuselage - Bonded Skin Doublers (Tear Straps) - Delamination Inspection and Repair" x. FAA Airworthiness Directive 03-14-06, Amendment 39-13225 y. FAA Airworthiness Directive 95-12-17, Amendment 39-9268 z. FAA Airworthiness Directive 88-22-11, Amendment 39-6432 aa. FAA Airworthiness Directive 89-09-03, Amendment 39-6184 ab. FAA Airworthiness Directive 91-08-12, Amendment 39-6967 ac. FAA Airworthiness Directive 92-25-09, Amendment 39-8424 ad. FAA Airworthiness Directive 98-11-04, Amendment 39-10984 ae. Boeing Drawing 65C36009 2. Data supplied with this Service Bulletin: a. Drawings: **Drawing Number Title Sheet DCN ADCN** 65C38491-1 (a) S-18A Preventive Modification KPL A - 65C38491-2 (a) KPL A - 65C38491 (a) 1 - -June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 77 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

65C37277-17 (a) Strap Installation - Station 727 Bulkhead, S-18 to S-20, Preventive Modification (Top Kit) KPL A - 65C37277-18 (a) KPL A - 65C37277-19 (a) KPL A - 65C37277-20 (a) KPL A - 65C37277-21 (a) KPL A - 65C37277-22 (a) KPL A - 65C37277-23 (a) KPL A - 65C37277-24 (a) KPL A - 65C37277-25 (a) KPL A - 65C37277-26 (a) KPL A - 65C37277 PL - 3 (a) 1- - 2 (a) - - 3 (a) - - 4 (a) - - 5 (a) - - 6 (a) - - 65C38642-1 (a) Strap Installation - S-18A Outboard Chord Repair - Station 727 KPL A - 65C38642-2 (a) KPL A - 65C38642-3 (a) KPL A - 65C38642-4 (a) KPL A - 65C38642-5 (a) KPL A - 65C38642-6 (a) KPL A - 65C38642-7 (a) KPL A - 65C38642-8 (a) KPL A - 65C38642-9 (a) KPL A - 65C38642-10 (a) KPL A - 65C38642 (a) 1 - - 2- - 3- - 4- - 5- - 65C37565 (b) Strap Installation - S-18A Outboard Chord Repair - Station 727 PL - - 1- - (a) Sent with Revision 2. (b) Sent with Revision 1. **Drawing Number Title Sheet DCN ADCN**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 78 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

3. Installation Drawings Used in the Preparation of this Service Bulletin:

These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators.
**K. Publications Affected**

**L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts. **Drawing Number Title** 65-45771 Skin Panel Installation - S-10 to S-18A, STA 540 to STA 727 65-45774 Skin Panel Installation - S-14L to S-25L, STA 727 to STA 908 65-45775 Skin Panel Installation - S-14R to S-25R, STA 727 to STA 908 65-45776 Skin Panel Installation - S-25L to S-25R, STA 727 to STA 1016 65-46547 Bulkhead installation - STA 727 65-46877 Strap and Beam Installation - Stringer 18A, STA 639 to STA 747 65-48654 Frame Installation - Aft Wing/Body Fairing, STA 729.38

**Publication Chapter-Section** 737 Non-Destructive Test Manual Part 4 and Part 6 737-100/200 Structural Repair Manual 53-10-2 737-300 Structural Repair Manual 53-10-00 737-400 Structural Repair Manual 53-10-00 737-500 Structural Repair Manual 53-10-00June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 79 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the kits/parts shown in Paragraph 2.C., Parts Necessary For Each Airplane as shown below. If there is a limit to the quantity (QTY) of available kits/parts, a supply sequence is given by Spares. More kits/parts become available as shown in the Reorder Lead Time (ROLT). ROLT is calculated from the date Boeing gets the purchase order.
**Kit/Part Number**  **Name Date QTY ROLT**  **(weeks) Unit Price thru**  **Jan 31/06** 65C37277-1 Top Kit, Left Side - - 48 $6,836.00 65C37277-2 Top Kit, Right Side - - 48 $6,836.00 65C37277-3 Top Kit, Left Side - - 48 $6,567.00 65C37277-4 Top Kit, Right Side - - 48 $6,567.00 65C37277-5 Top Kit, Left Side - - 48 $6,583.00 65C37277-6 Top Kit, Right Side - - 48 $6,583.00 65C37277-7 Top Kit, Left Side Inactive for procurement 65C37277-8 Top Kit, Right Side Inactive for procurement 65C37565-1 Top Kit, Left Side Inactive for procurement 65C37565-2 Top Kit, Right Side Inactive for procurement 65C37565-3 Top Kit, Left Side Inactive for procurement 65C37565-4 Top Kit, Right Side Inactive for procurement 65C37565-5 Top Kit, Left Side - - 48 $5,357.00 65C37565-6 Top Kit, Right Side - - 48 $5,357.00 65C37565-7 Top Kit, Left Side - - 48 $4,937.00 65C37565-8 Top Kit, Right Side - - 48 $4,937.00 65C37277-17 Top Kit, Left Side March/21/06 5 48 $6,642.00 65C37277-18 Top Kit, Right Side March/21/06 5 48 $6,642.00 65C37277-19 Top Kit, Left Side March/21/06 10 48 $6,393.00 March/24/06 10 March/29/06 5 65C37277-20 Top Kit, Right Side March/21/06 10 48 $6,393.00 March/24/06 10 March/29/06 5 65C37277-21 Top Kit, Left Side March/21/06 1 48 $6,405.00 65C37277-22 Top Kit, Right Side March/21/06 1 48 $6,405.00 65C37277-23 Top Kit, Left Side March/21/06 1 48 $6,198.00 65C37277-24 Top Kit, Right Side March/21/06 1 48 $6,198.00 65C37277-25 Top Kit, Left Side March/21/06 1 48 $6,257.00 65C37277-26 Top Kit, Right Side March/21/06 1 48 $6,257.00 65C38491-1 Top Kit, Left Side - - 48 $3,545.00June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 80 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. After the Unit Price date, new price (and ROLT) data is applicable. Prices are in United States Dollars. Terms: Net 30 days. Send purchase orders and letters about the supply data to the Director of Spares and refer to this service bulletin number. **B. Industry Support Information** Boeing warranty remedies are not available for the inspection and /or repair procedures given in this service bulletin. 65C38491-2 Top Kit, Right Side - - 48 $3,545.00 65C38642-1 Top Kit, Left Side - - 48 $8,279.00 65C38642-2 Top Kit, Right Side - - 48 $8,279.00 65C38642-3 Top Kit, Left Side - - 48 $8,256.00 65C38642-4 Top Kit, Right Side - - 48 $8,256.00 65C38642-5 Top Kit, Left Side - - 48 $8,206.00 65C38642-6 Top Kit, Right Side - - 48 $8,308.00 65C38642-7 Top Kit, Left Side - - 48 $8,932.00 65C38642-8 Top Kit, Right Side - - 48 $8,932.00 65C38642-9 Top Kit, Left Side - - 48 $8,493.00 65C38642-10 Top Kit, Right Side - - 48 $8,493.00 65C38643-1 Shear Beam Web, Left Side - - 48 $519.00
65C38643-2 Shear Beam Web, Right Side - - 48 $519.00
69-78347-1 Shear Beam Web, Left Side - - 48 $519.00
69-78347-2 Shear Beam Web, Right Side - - 48 $519.00 **Kit/Part Number**  **Name Date QTY ROLT**  **(weeks) Unit Price thru**  **Jan 31/06**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 81 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT C. Parts Necessary For Each Airplane** 
1. Kits/Parts: **Usage Kit Number Effectivity Kit Action Remarks** STA 727 Frame Preventive Modification (without S-18A Preventive Modification) 65C37277-1 (Left Side) Group 1 (a) Install external strap for Frame Preventive Modification (1) Concurrent incorporation of 65C38491-1/-2 (add S-18A Preventive Modification) recommended. (2) If S-18A Chord Repair is needed, see 65C38642. (Note 65C37565 repair kits are also satisfactory for usage, however they are not compatible with 65C33722 Frame replacement kit). S-18A Chord is 0.20 inch thick with early frames. 65C37277-2 (Right Side) 65C37277-3 (Left Side) Group 1 (b) 65C37277-4 (Right Side) 65C37277-5 (Left Side) Group 2 65C37277-6 (Right Side)

S-18A Chord Preventive Modification 65C38491-1 (Left Side) Group 1 and 2 Install external strap for S-18A Chord Preventive Modification (1) For use with Frame Preventive Modification 65C37277-1 through -6. (2) For airplanes that have incorporated 65C37277-( ), see flag notes on 65C38491-( ) for fastener information. S-18A Chord is 0.20 inch thick. 65C38491-2 (Right Side)

STA 727 Frame and S-18A Chord Preventive Modification Combination 65C37277-17 (Left Side) Group 3 and 4 Install external straps for Frame Preventive Modification and S-18A Chord Preventive Modification Kit includes both Frame and S-18A Preventive Modification Strap. S-18A Chord is 0.33 thick, early skin panels and early fairing panels. 65C37277-18 (Right Side)

65C37277-19 (Left Side) Group 5 and 10 Kit includes both Frame and S-18A Preventive Modification Strap. S-18A Chord is 0.33 inch thick, later skin panels and early fairing panels. 65C37277-20 (Right Side)

65C37277-21 (Left Side) Group 6 and 9 (c) Kit includes both Frame and S-18A Preventive Modification Strap. S-18A Chord is 0.33 inch thick, later skin panels and later fairing panels. 65C37277-22 (Right Side)

STA 727 Frame Preventive Modification 65C37277-23 (Left Side) Group 7 and 11 Install external straps for Frame Preventive Modification Kit includes Frame Preventive Modification only. S-18A Chord is 0.40 or 0.45 inch thick, later skin panels and early fairing panels. 65C37277-24 (Right Side)

65C37277-25 (Left Side) Group 8 and 9 (d) Kit includes Frame Preventive Modification only. S-18A Chord is 0.40 or 0.45 inch thick, later skin panels and later fairing panels. 65C37277-26 (Right Side)June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 82 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

S-18A Chord Repair 65C37565-5 (Left Side) Group 1 (b) Install external strap for S-18A Chord repair Not compatible with 65C33722 Frame replacement. See 65C38642-7/-8 or - 9/-10. 65C37565-1 through -4 are used without 65C37277-1 through -6 installed (obsolete). Superseded by 65C38642-7/-8 or-9/-10. 65C37565-5 through -8 are used with 65C37277-1 through -6 installed. S-18A Chord is 0.20 inch thick. 65C37565-6 (Right Side) 65C37565-7 (Left Side) Group 2 65C37565-8 (Right Side)

S-18A Chord Repair 65C38642-7 (Left Side) Group 1 (b) Install external strap for Frame Modification and S-18A Chord Repair. Kit includes S-18A Chord Repair and Frame Preventive Modification straps (Tee S-18A Chord). S-18A Chord is 0.20 inch thick. 65C38642-8 (Right Side)

S-18A Chord Repair 65C38642-9 (Left Side) Group 2 Install external strap for Frame Modification and S-18A Chord Repair. Kit includes S-18A Chord Repair and Frame Preventive Modification straps (Flat S-18A Chord). S-18A Chord is 0.20 inch thick. 65C38642-10 (Right Side)

S-18A Chord Repair 65C38642-5 (Left Side) Group 3 and 4 Install external strap for Frame Modification and S-18A Chord Repair. Kit includes S-18A Chord Repair and Frame Preventive Modification straps. S-18A Chord is 0.33 inch thick, early skin panels and early fairings. 65C38642-6 (Right Side)

S-18A Chord Repair 65C38642-1 (Left Side) Group 5 and 10 Install external strap for Frame Modification and S-18A Chord Repair. Kit includes S-18A Chord Repair and Frame Preventive Modification straps. S-18A Chord is 0.33 inch thick, later skin panels and early fairings. 65C38642-2 (Right Side) **Usage Kit Number Effectivity Kit Action Remarks**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 83 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. S-18A Chord Repair 65C38642-3 (Left Side) Group 6 and 9 (c) Install external strap for Frame Modification and S-18A Chord Repair Kit includes S-18A Chord Repair and Frame Preventive Modification straps. S-18A Chord is 0.33 inch thick, later skin panels and later fairings. 65C38642-4 (Right Side)

(a) For Group 1 Airplanes, Line Number 1-23 only. (b) For Group 1 Airplanes, Line Number 24-310 only. (c) This kit is only applicable to one side of Group 9 airplanes where the S-18A Chord thickness is 0.33inches. (d) This kit is only applicable to one side of Group 9 airplanes where the S-18A Chord thickness is 0.40 or 0.45 inches.

Group 1and 2 **Kit 65C37277 - STA 727 Frame Preventive Modifi cation (Without S-18A Preventive Modification)** 

**New Part Number QTY** 

**Name Notes -6 -5 -4 -3 -2 -1**  65C37277-1 . . . . . - PREVENTIVE MOD KIT - LEFT SIDE (a)

65C37277-2 . . . . - . PREVENTIVE MOD KIT - RIGHT SIDE (a)

65C37277-3 . . . - . . PREVENTIVE MOD KIT - LEFT SIDE (b)

65C37277-4 . . - . . . PREVENTIVE MOD KIT - RIGHT SIDE (b)

65C37277-5 . - . . . . PREVENTIVE MOD KIT - LEFT SIDE (c)

65C37277-6 - . . . . . PREVENTIVE MOD KIT - RIGHT SIDE (c)

65C37277-11 1 1 1 1 1 1 FILLER - TAPERED 65C37277-12 . . . . 1 1 FASTENER ASSY 65C37277-13 . . 1 1 . . FASTENER ASSY 65C37277-14 1 1 . . . . FASTENER ASSY 65-48654-10 2 2 2 2 2 2 FILLER - TAPERED 65-48654-14 1 1 1 1 1 1 FILLER - FLAT 69-78767-3 . 1 . 1 . . ATTACH ANGLE 69-78767-4 1 . 1 . . . ATTACH ANGLE **Usage Kit Number Effectivity Kit Action Remarks**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 84 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

69-78767-5 . . . . . 1 ATTACH ANGLE 69-78767-6 . . . . 1 . ATTACH ANGLE 69-78768-2 1 1 1 1 . . WEB 69-78768-3 . . . . 1 1 WEB 69-78769-1 . 1 1 . . STIFFENER 69-78769-2 1 . 1 . . . STIFFENER 69-78769-3 . . . . . 1 STIFFENER 69-78769-4 . . . . 1 . STIFFENER 69-78769-5 . 1 . 1 . 1 ANGLE 69-78769-6 1 . 1 . 1 . ANGLE 69-78770-1 . 1 . 1 . 1 STRAP-EXTERNAL 69-78770-2 1 . 1 . 1 . STRAP-EXTERNAL 69-78773-1 1 1 1 1 . . FILLER - FLAT 69-78773-2 . . . . 1 1 FILLER - FLAT 69-78773-3 . . . . 1 1 FILLER - TAPERED 69-78773-4 . . . . 1 1 FILLER - TAPERED 69-78773-5 . . . . 1 1 FILLER - TAPERED 69-78773-6 1 1 1 1 . . FILLER - TAPERED 69-78773-7 1 1 1 1 . . FILLER - TAPERED 69-78773-8 1 1 1 1 . . FILLER - TAPERED 69-78773-10 1 1 1 1 . . SHIM - LAMINATED BACF3F008W011NG 1 1 1 1 1 1 FILLER - FLAT BACF3F023L083AG . . . . 2 2 FILLER - FLAT (a) For Group 1 airplanes, Line numbers 1 - 23 only. (b) For Group 1 airplanes, Line numbers 24 - 310 only. (c) For Group 2 airplanes. Group 1and 2 **Kit 65C37277 - STA 727 Frame Preventive Modifi cation (Without S-18A Preventive Modification)** 

**New Part Number QTY** 

**Name Notes -6 -5 -4 -3 -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 85 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** Group 3, 4, 5, 6, 9 and 10 **Kit 65C37277 - STA 727 Frame and S-18A Preventive Modification Combination**

**New Part Number QTY**  **Name Notes -22 -21 -20 -19 -18 -17**  65C37277-17 . . . . . - STA 727 FRAME AND S-18A MOD KIT (a)

65C37277-18 . . . . - . STA 727 FRAME AND S-18A MOD KIT (a)

65C37277-19 . . . - . . STA 727 FRAME AND S-18A MOD KIT (b)

65C37277-20 . . - . . . STA 727 FRAME AND S-18A MOD KIT (b)

65C37277-21 . - . . . . STA 727 FRAME AND S-18A MOD KIT (c) (d)

65C37277-22 - . . . . . STA 727 FRAME AND S-18A MOD KIT (c) (d)

65-48654-82 2 2 2 2 2 2 FILLER 65-48654-84 3 3 3 3 3 3 FILLER 65C37277-11 1 1 1 1 1 1 FILLER-TAPERED 65C38496-1 1 1 1 1 1 1 STRAP S-18A OUTBD CHORD MOD, STA 727 DETAIL. 69-78767-7 . . . 1 . 1 ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78767-8 . . 1 . 1 . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78767-9 . 1 . . . . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78768-4 . . 1 1 1 1 WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78768-5 1 1 . . . . WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-5 . . . 1 . 1 ANGLE 69-78769-6 . . 1 . 1 . ANGLE 69-78769-7 . 1 . . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 86 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

69-78769-8 1 . . . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-9 . . . 1 . 1 STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78770-3 . 1 . 1 . 1 STRAP-EXTERNAL, STA 727 69-78770-4 1 . 1 . 1 . STRAP-EXTERNAL, STA 727 69-78773-1 . . . . 1 1 FILLER-FLAT 69-78773-6 1 1 1 1 . . FILLER-TAPERED 69-78773-7 . . . . 1 1 FILLER-TAPERED 69-78773-9 . . . . 1 1 FILLER 69-78767-10 1 . . . . . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-10 . . 1 . 1 . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-11 . 1 . . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-12 1 . . . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78773-10 . . . . 1 1 SHIM,LAMINATED 69-78773-11 1 1 1 1 . . FILLER-DETAILS 69-78773-12 1 1 1 1 . . FILLER DETAILS 69-78773-13 . . . . 1 1 FILLER DETAILS 69-78773-14 1 1 1 1 . . FILLER-DETAILS 69-78773-15 1 1 1 1 . . FILLER-DETAILS 69-78773-16 1 1 1 1 1 1 FILLER DETAILS BACB30MB10A16 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MB10A17 1 1 1 1 3 3 BOLT, PROTRUDING HD (e) Group 3, 4, 5, 6, 9 and 10 **Kit 65C37277 - STA 727 Frame and S-18A Preventive Modification Combination**

**New Part Number QTY**  **Name Notes -22 -21 -20 -19 -18 -17** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 87 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30MB10A18 2 2 2 2 . . BOLT, PROTRUDING HD (e)
BACB30MB10A19 2 2 2 2 2 2 BOLT, HEX DRIVE (e) BACB30MY8K10Y 3 3 3 3 2 2 BOLT, PROTRUDING HD (e)
BACB30MY8K11X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K11Y 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K12Y 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MY8K13Y 2 2 2 2 2 2 BOLT, PROTRUDING HD (e)
BACB30MY8K14X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K14Y 8 8 8 8 8 8 BOLT, PROTRUDING HD (e)
BACB30MY8K15Y 7 7 7 7 7 7 BOLT, PROTRUDING HD (e)
BACB30MY8K16X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K16Y 7 7 7 7 7 7 BOLT, PROTRUDING HD (e)
BACB30MY8K17Y 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MY8K18Y 6 6 6 6 6 6 BOLT, PROTRUDING HD (e)
BACB30MY8K20Y 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K6X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K7X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K7Y 25 25 25 25 25 25 BOLT, PROTRUDING HD (e)
BACB30MY8K8X 6 6 6 6 6 6 BOLT, PROTRUDING HD (e)
BACB30MY8K8Y 9 9 9 9 9 9 BOLT, PROTRUDING HD (e)
BACB30MY8K9Y 4 4 4 4 4 4 BOLT, PROTRUDING HD (e) Group 3, 4, 5, 6, 9 and 10 **Kit 65C37277 - STA 727 Frame and S-18A Preventive Modification Combination**

**New Part Number QTY**  **Name Notes -22 -21 -20 -19 -18 -17** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 88 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30NX6K3 7 7 7 7 7 7 BOLT, PROTRUDING HD (e)
BACB30NX6K4 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30NX6K4X 9 9 9 9 9 9 BOLT, PROTRUDING HD (e)
BACB30NX6K5X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30NX8K7 5 5 5 5 5 5 BOLT, HEX DRIVE (e) BACB30YP6K5 2 2 2 2 2 2 BOLT, 100 DEG HEX DR (e)
BACB30YP8K5 1 1 1 1 1 1 BOLT, 100 DEG HEX DR (e)

BACC30BH10 8 8 8 8 8 8 COLLAR BACC30BH6 10 10 10 10 10 10 COLLAR BACC30BH8 5 5 5 5 5 5 COLLAR BACC30BL6 2 2 2 2 2 2 COLLAR BACC30BL8 1 1 1 1 1 1 COLLAR BACC30M6 10 10 10 10 10 10 COLLAR BACC30M8 11 11 11 11 12 12 COLLAR BACC30R8 86 86 86 86 86 86 COLLAR BACF3F009N010NN 1 1 1 1 1 1 FILLER, FLAT. BACF3T01E07-10 1 1 1 1 1 1 TAPERED FILLER BACF3T03R34-10 1 1 1 1 1 1 FILLER, TAPERED BACF3T04R26-10 1 1 1 1 1 1 FILLER, TAPERED. BACR15BB6D6C 45 45 45 45 45 45 RIVET, UNIVERSAL HD (e)
BACR15BB6D7C 7 7 7 7 7 7 RIVET, UNIVERSAL HD (e)
BACS40R010B046F . . . . 1 1 SHIM, LAMINATED BACS40R010B054F 1 1 1 1 1 1 SHIM, LAMINATED BACS40R021B097F 1 1 1 1 . . SHIM, LAMINATED BACW10BN31AP 10 10 10 10 10 10 WASHER, PLAIN BACW10BN3AP 12 12 12 12 12 12 WASHER BACW10BN41AP 10 10 10 10 10 10 WASHER, COUNTERSUNK, OVERSIZE Group 3, 4, 5, 6, 9 and 10 **Kit 65C37277 - STA 727 Frame and S-18A Preventive Modification Combination**

**New Part Number QTY**  **Name Notes -22 -21 -20 -19 -18 -17** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 89 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACW10BN42AP 86 86 86 86 86 86 WASHER, COUNTERSUNK, OVERSIZE BACW10BN4AP 6 6 6 6 6 6 WASHER, PLAIN BACW10BN5AP 8 8 8 8 8 8 WASHER, COUNTERSUNK, OVERSIZEBACW10CA104CC 39 39 39 39 39 39 WASHER, SELFALIGNBACW10CA104CV 38 38 38 38 38 38 WASHER, SELFALIGNBACW10CA104PV 1 1 1 1 1 1 WASHER, SELFALIGN BACW10CA5CC 8 8 8 8 8 8 WASHER BACW10CA5CV 8 8 8 8 8 8 WASHER (a) For Group 3 and 4 airplanes. (b) For Group 5 and 10 airplanes. (c) For Group 6 and 9 airplanes. (d) This kit is only applicable to one side of Group 9 airplanes where the S-18A Chord thickness is 0.33inches. (e) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Boeing Document D-590 and Boeing Drawing 65-88700 are used to determine the part numbers used as substitutes. Group 7, 8, 9 and 11 **Kit 65C37277 - STA 727 Frame Preventive Modification**

**New Part Number QTY**  **Name Notes -26 -25 -24 -23**  65C37277-23 . . . - STA 727 FRAME PREVENTIVE MODIFICATION (a) 65C37277-24 . . - . STA 727 FRAME PREVENTIVE MODIFICATION (a) 65C37277-25 . - . . STA 727 FRAME PREVENTIVE MODIFICATION (b) (c) 65C37277-26 - . . . STA 727 FRAME PREVENTIVE MODIFICATION (b) (c) 65-48654-82 2 2 2 2 FILLER 65-48654-84 3 3 3 3 FILLER 65C37277-11 1 1 1 1 FILLER-TAPERED 69-78767-7 . . . 1 ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 Group 3, 4, 5, 6, 9 and 10 **Kit 65C37277 - STA 727 Frame and S-18A Preventive Modification Combination**

**New Part Number QTY**  **Name Notes -22 -21 -20 -19 -18 -17** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 90 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

69-78767-8 . . 1 . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78767-9 . 1 . . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78768-4 . . 1 1 WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78768-5 1 1 . . WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-5 . . . 1 ANGLE 69-78769-6 . . 1 . ANGLE 69-78769-7 . 1 . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-8 1 . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-9 . . . 1 STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78770-3 . 1 . 1 STRAP-EXTERNAL, STA 727 69-78770-4 1 . 1 . STRAP-EXTERNAL, STA 727 69-78773-6 1 1 1 1 FILLER-TAPERED 69-78767-10 1 . . . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-10 . . 1 . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-11 . 1 . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-12 1 . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38 69-78773-11 1 1 1 1 FILLER-DETAILS 69-78773-12 1 1 1 1 FILLER DETAILS 69-78773-14 1 1 1 1 FILLER-DETAILS 69-78773-15 1 1 1 1 FILLER-DETAILS 69-78773-16 1 1 1 1 FILLER DETAILS BACB30MB10A16 2 2 2 2 BOLT, PROT RUDING HD (d) BACB30MB10A17 2 2 2 2 BOLT, PROT RUDING HD (d) BACB30MB10A18 2 2 2 2 BOLT, PROT RUDING HD (d) BACB30MB10A19 2 2 2 2 BOLT, HEX DRIVE (d) BACB30MY8K10Y 3 3 3 3 BOLT, PROT RUDING HD (d) BACB30MY8K11X 1 1 1 1 BOLT, PROT RUDING HD (d) Group 7, 8, 9 and 11 **Kit 65C37277 - STA 727 Frame Preventive Modification**

**New Part Number QTY**  **Name Notes -26 -25 -24 -23** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 91 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30MY8K11Y 3 3 3 3 BOLT, PROT RUDING HD (d) BACB30MY8K12Y 4 4 4 4 BOLT, PROT RUDING HD (d) BACB30MY8K13Y 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30MY8K14X 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30MY8K14Y 6 6 6 6 BOLT, PROT RUDING HD (d) BACB30MY8K15Y 6 6 6 6 BOLT, PROT RUDING HD (d) BACB30MY8K16X 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30MY8K16Y 8 8 8 8 BOLT, PROT RUDING HD (d) BACB30MY8K17Y 5 5 5 5 BOLT, PROT RUDING HD (d) BACB30MY8K18Y 6 6 6 6 BOLT, PROT RUDING HD (d) BACB30MY8K20Y 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30MY8K6X 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30MY8K7X 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30MY8K7Y 23 23 23 23 BOLT, PROTRUDING HD (d) BACB30MY8K8X 6 6 6 6 BOLT, PROT RUDING HD (d) BACB30MY8K8Y 8 8 8 8 BOLT, PROT RUDING HD (d) BACB30MY8K9Y 4 4 4 4 BOLT, PROT RUDING HD (d) BACB30NX6K3 7 7 7 7 BOLT, PROT RUDING HD (d) BACB30NX6K4 3 3 3 3 BOLT, PROT RUDING HD (d) BACB30NX6K4X 9 9 9 9 BOLT, PROT RUDING HD (d) BACB30NX6K5X 1 1 1 1 BOLT, PROT RUDING HD (d) BACB30NX8K7 5 5 5 5 BOLT, HEX DRIVE (d) BACB30YP6K5 2 2 2 2 BOLT, 100 DEG HEX DR (d) BACB30YP8K5 1 1 1 1 BOLT, 100 DEG HEX DR (d) BACC30BH10 8 8 8 8 COLLAR BACC30BH6 10 10 10 10 COLLAR BACC30BH8 5 5 5 5 COLLAR BACC30BL6 2 2 2 2 COLLAR BACC30BL8 1 1 1 1 COLLAR BACC30M6 10 10 10 10 COLLAR BACC30M8 12 12 12 12 COLLAR BACC30R8 86 86 86 86 COLLAR BACF3F009N010NN 1 1 1 1 FILLER, FLAT. BACF3F010G025NN 2 2 2 2 FILLER BACF3T01E07-10 1 1 1 1 TAPERED FILLER BACF3T03R34-10 1 1 1 1 FILLER, TAPERED Group 7, 8, 9 and 11 **Kit 65C37277 - STA 727 Frame Preventive Modification**

**New Part Number QTY**  **Name Notes -26 -25 -24 -23** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 92 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACF3T04R26-10 1 1 1 1 FILLER, TAPERED. BACR15BB6D6C 45 45 45 45 RIVET, UNIVERSAL HD (d) BACR15BB6D7C 7 7 7 7 RIVET, UNIVERSAL HD (d) BACS40R010B054F 1 1 1 1 SHIM, LAMINATED BACS40R021B097F 1 1 1 1 SHIM, LAMINATED BACW10BN31AP 10 10 10 10 WASHER, PLAIN BACW10BN3AP 12 12 12 12 WASHER BACW10BN41AP 10 10 10 10 WASHER, COUNTERSUNK, OVERSIZE BACW10BN42AP 86 86 86 86 WASHER, COUNTERSUNK, OVERSIZE BACW10BN4AP 6 6 6 6 WASHER, PLAIN BACW10BN5AP 8 8 8 8 WASHER, COUNTERSUNK, OVERSIZE BACW10CA104CC 39 39 39 39 WASHER, SELF-ALIGN BACW10CA104CV 38 38 38 38 WASHER, SELF-ALIGN BACW10CA104PV 1 1 1 1 WASHER, SELF-ALIGN BACW10CA5CC 8 8 8 8 WASHER BACW10CA5CV 8 8 8 8 WASHER (a) For Group 7 and 11 airplanes. (b) For Group 8 and 9 airplanes. (c) This kit is only applicable to one side of Group 9 airplanes where the S-18A Chord thickness is 0.40 or 0.45 inches. (d) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Boeing Document D-590 and Boeing Drawing 65-88700 are used to determine the part numbers used as substitutes. Group 1 and 2 **Kit 65C37565 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -8 -7 -6 -5**  65C37565-5 . . . - S-18A REPAIR KIT - LEFT SIDE (a) 65C37565-6 . . - . S-18A REPAIR KIT - RIGHT SIDE (a) 65C37565-7 . - . . S-18A REPAIR KIT - LEFT SIDE (b) 65C37565-8 - . . . S-18A REPAIR KIT - RIGHT SIDE (b) 65C37565-17 1 1 1 1 FASTENER KIT 65C37566-10 1 1 1 1 FILLER 65C37566-2 1 1 1 1 STRAP 65C37566-3 1 1 1 1 STRAP Group 7, 8, 9 and 11 **Kit 65C37277 - STA 727 Frame Preventive Modification**

**New Part Number QTY**  **Name Notes -26 -25 -24 -23** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 93 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

65C37566-4 1 1 1 1 STRAP 65C37566-5 . . . 1 STRAP 65C37566-6 . . 1 . STRAP 65C37566-7 . 1 . . STRAP 65C37566-8 1 . . . STRAP 65C37566-9 1 1 1 1 FILLER 69-87822-1 . 1 . 1 SPLICE ANGLE 69-87822-2 1 . 1 . SPLICE ANGLE BACF3F008J017NN 1 1 1 1 FILLER BACF3F016J018NN 1 1 1 1 FILLER BACS40R023B027P 1 1 1 1 SHIM, LAMINATED 65C37565-10 1 . 1 . STIFFENER 65C37565-11 . 1 . 1 ATTACH ANGLE 65C37565-12 1 . 1 . ATTACH ANGLE 65C37565-13 . 1 . 1 ATTACH ANGLE 65C37565-14 1 . 1 . ATTACH ANGLE 65C37565-15 1 1 1 1 WEB 65C37565-9 . 1 . 1 STIFFENER (a) For Group 1 airplanes, Line numbers 24 - 310 only. (b) For Group 2 airplanes. Group 1 and 2 **Kit 65C38491 - S-18A Chord Preventive Modification**

**New Part Number QTY**  **Name Notes -2 -1**  65C38491-1 . - S-18A PREVENTIVE MOD 65C38491-2 - . S-18A PREVENTIVE MOD 65-46877-31 1 1 FILLER-TAPERED 65-48654-82 2 2 FILLER 65-48654-84 3 3 FILLER 65C38496-1 1 1 STRAP S-18A OUTBD CHORD MOD, STA 727 DETAIL. 69-78767-7 . 1 ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78767-8 1 . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 Group 1 and 2 **Kit 65C37565 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -8 -7 -6 -5** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 94 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

69-78768-4 1 1 WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-9 . 1 STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-10 1 . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 BACB30MB10A14 2 2 BOLT, PROTRUDING HD (a) BACB30MB10A15 2 2 BOLT, PROTRUDING HD (a) BACB30MB10A16 4 4 BOLT, PROTRUDING HD (a) BACB30MB10A17 4 4 BOLT, PROTRUDING HD (a) BACB30MB10A18 2 2 BOLT, PROTRUDING HD (a) BACB30MB10A19 2 2 BOLT, HEX DRIVE (a) BACB30MC10A14 2 2 BOLT, PROTRUDING HD (a) BACB30MC10A15 2 2 BOLT, PROTRUDING HD (a) BACB30MC10A16 4 4 BOLT, PROTRUDING HD (a) BACB30MC10A17 4 4 BOLT, PROTRUDING HD (a) BACB30MC10A18 2 2 BOLT, PROTRUDING HD (a) BACB30MC10A19 2 2 BOLT, HEX DRIVE (a) BACB30MY8K10X 1 1 BOLT, PROTRUDING HD (a) BACB30MY8K10Y 2 2 BOLT, PROTRUDING HD (a) BACB30MY8K11X 2 2 BOLT, PROTRUDING HD (a) BACB30MY8K11Y 7 7 BOLT, PROTRUDING HD (a) BACB30MY8K12X 1 1 BOLT, PROTRUDING HD (a) BACB30MY8K12Y 11 11 BOLT, PROTRUDING HD (a) BACB30MY8K13Y 7 7 BOLT, PROTRUDING HD (a) BACB30MY8K14Y 5 5 BOLT, PROTRUDING HD (a) BACB30MY8K15Y 5 5 BOLT, PROTRUDING HD (a) BACB30MY8K16Y 2 2 BOLT, PROTRUDING HD (a) BACB30MY8K17Y 2 2 BOLT, PROTRUDING HD (a) BACB30MY8K18Y 1 1 BOLT, PROTRUDING HD (a) BACB30MY8K7X 5 5 BOLT, PROTRUDING HD (a) BACB30MY8K7Y 12 12 BOLT, PROTRUDING HD (a) BACB30MY8K8X 1 1 BOLT, PROTRUDING HD (a) BACB30MY8K8Y 1 1 BOLT, PROTRUDING HD (a) BACB30MY8K9X 6 6 BOLT, PROTRUDING HD (a) BACB30MY8K9Y 13 13 BOLT, PROTRUDING HD (a) Group 1 and 2 **Kit 65C38491 - S-18A Chord Preventive Modification**

**New Part Number QTY**  **Name Notes -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 95 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30NX6K3 7 7 BOLT, PROTRUDING HD (a) BACB30NX6K4 4 4 BOLT, PROTRUDING HD (a) BACB30NX6K4X 9 9 BOLT, PROTRUDING HD (a) BACC30BH10 8 8 COLLAR BACC30BH6 11 11 COLLAR BACC30M6 9 9 COLLAR BACC30M8 9 9 COLLAR BACC30R8 37 37 COLLAR BACF3F010N027NN 1 1 FILLER BACF3T01E07-10 1 1 TAPERED FILLER BACF3T03R34-10 1 1 FILLER, TAPERED BACF3T04R26-10 1 1 FILLER, TAPERED. BACR15BB6D6C 40 40 RIVET, UNIVERSAL HD (a) BACR15BB8D5C 2 2 RIVET, UNIVERSAL HD (a) BACS40R010B027F 1 1 SHIM, LAMINATED BACS40R010E045F 1 1 SHIM, LAMINATED BACS40R010E055F 1 1 SHIM, LAMINATED BACW10BN31AP 9 9 WASHER, PLAIN BACW10BN3AP 9 9 WASHER BACW10BN41AP 9 9 WASHER, COUNTERSUNK, OVERSIZE BACW10BN42AP 25 25 WASHER, COUNTERSUNK, OVERSIZE BACW10BN5AP 8 8 WASHER, COUNTERSUNK, OVERSIZE BACW10CA104CC 13 13 WASHER, SELF-ALIGN BACW10CA104CV 13 13 WASHER, SELF-ALIGN BACW10CA5CC 8 8 WASHER BACW10CA5CV 8 8 WASHER (a) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Boeing Document D-590 and Boeing Drawing 65-88700 are used to determine the part numbers used as substitutes. Group 1 and 2 **Kit 65C38491 - S-18A Chord Preventive Modification**

**New Part Number QTY**  **Name Notes -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 96 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** Group 3, 4, 5, 6, 9 and 10 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -6 -5 -4 -3 -2 -1**  65C38642-1 . . . . . - S-18A REPAIR (a) 65C38642-2 . . . . - . S-18A REPAIR (a) 65C38642-3 . . . - . . S-18A REPAIR (b) (c) 65C38642-4 . . - . . . S-18A REPAIR (b) (c) 65C38642-5 . - . . . . S-18A REPAIR (d) 65C38642-6 - . . . . . S-18A REPAIR (d) 65-48654-84 3 3 3 3 3 3 FILLER 65C37277-11 1 1 1 1 1 1 FILLER-TAPERED 65C37566-3 . . 1 1 1 1 STRAP 65C37566-12 1 1 1 1 1 1 STRAP S-18A OUTBD CHORD REPAIR, STA 727, KIT 65C37566-15 . 1 . 1 . 1 STRAP S-18A OUTBD CHORD REPAIR, STA 727, KIT 65C37566-16 1 . 1 . 1 . STRAP S-18A OUTBD CHORD REPAIR, STA 727, KIT 65C37566-17 1 1 . . . . STRAP S-18A OUTBD CHORD REPAIR, STA 727, KIT 65C37566-18 1 1 1 1 1 1 STRAP S-18A OUTBD CHORD REPAIR, STA 727, KIT 69-78768-6 1 1 . . 1 1 WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78768-7 . . 1 1 . . WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-5 . 1 . . . 1 ANGLE 69-78769-6 1 . . . 1 . ANGLE 69-78769-7 . . . 1 . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.38June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 97 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

69-78769-8 . . 1 . . . DETAILS - AFT WING BODY FAIRING, STA 727 + 2.3869-78770-3 . 1 . 1 . 1 STRAPEXTERNAL, STA 72769-78770-4 1 . 1 . 1 . STRAPEXTERNAL, STA 727 69-78773-1 1 1 . . . . FILLER-FLAT 69-78773-7 1 1 . . . . FILLER-TAPERED 69-78773-9 1 1 . . . . FILLER 69-78767-11 . 1 . 1 . 1 ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78767-12 1 . 1 . 1 . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-13 . 1 . . . 1 STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-14 1 . . . 1 . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-15 . . . 1 . . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-16 . . 1 . . . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78773-11 . . 1 1 1 1 FILLER-DETAILS 69-78773-12 . . 1 1 1 1 FILLER DETAILS 69-78773-14 . . 1 1 1 1 FILLER-DETAILS 69-78773-15 . . 1 1 1 1 FILLER-DETAILS 69-78773-16 1 1 1 1 1 1 FILLER DETAILS Group 3, 4, 5, 6, 9 and 10 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -6 -5 -4 -3 -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 98 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30MB10A17 2 2 2 2 2 2 BOLT, PROTRUDING HD (e)
BACB30MB10A18 4 4 4 4 4 4 BOLT, PROTRUDING HD (e)
BACB30MB10A20 2 2 2 2 2 2 BOLT, PROTRUDING HD (e)
BACB30MY8K10Y 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MY8K11X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K12Y 2 2 2 2 2 2 BOLT, PROTRUDING HD (e)
BACB30MY8K14X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K14Y 12 12 12 12 12 12 BOLT, PROTRUDING HD (e)
BACB30MY8K15Y 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MY8K16X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K16Y 11 11 11 11 11 11 BOLT, PROTRUDING HD (e)
BACB30MY8K17Y 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MY8K18Y 6 6 6 6 6 6 BOLT, PROTRUDING HD (e)
BACB30MY8K21Y 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K5Y 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30MY8K6X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K7X 1 1 3 3 1 1 BOLT, PROTRUDING HD (e)
BACB30MY8K7Y 23 23 23 23 23 23 BOLT, PROTRUDING HD (e)
BACB30MY8K8X 6 6 6 6 6 6 BOLT, PROTRUDING HD (e)
BACB30MY8K8Y 9 9 9 9 9 9 BOLT, PROTRUDING HD (e) Group 3, 4, 5, 6, 9 and 10 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -6 -5 -4 -3 -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 99 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30MY8K9Y 2 2 2 2 2 2 BOLT, PROTRUDING HD (e)
BACB30NX6K3 7 7 7 7 7 7 BOLT, PROTRUDING HD (e)
BACB30NX6K4 3 3 3 3 3 3 BOLT, PROTRUDING HD (e)
BACB30NX6K4X 9 9 9 9 9 9 BOLT, PROTRUDING HD (e)
BACB30NX6K5X 1 1 1 1 1 1 BOLT, PROTRUDING HD (e)
BACB30NX8K7 5 5 5 5 5 5 BOLT, HEX DRIVE (e) BACB30YP6K5 2 2 2 2 2 2 BOLT, 100 DEG HEX DR (e)
BACB30YP8K5 1 1 1 1 1 1 BOLT, 100 DEG HEX DR (e)

BACC30BH10 8 8 8 8 8 8 COLLAR BACC30BH6 10 10 10 10 10 10 COLLAR BACC30BH8 5 5 5 5 5 5 COLLAR BACC30BL6 2 2 2 2 2 2 COLLAR BACC30BL8 1 1 1 1 1 1 COLLAR BACC30M6 10 10 10 10 10 10 COLLAR BACC30M8 11 11 11 11 11 11 COLLAR BACC30R8 86 86 86 86 86 86 COLLAR BACF3F009N010NN . . 1 1 1 1 FILLER, FLAT. BACF3F009P010NN 1 1 . . . . FILLER BACF3F010A030BN 1 1 . . . . FILLER, FLAT BACF3F024A166BN 1 1 . . . . FILLER, FLAT BACF3T01F08-10B 3 3 3 3 3 3 FILLER BACF3T01T36-10 1 1 1 1 1 1 FILLER, TAPERED. BACF3T01T38-10 1 1 1 1 1 1 FILLER, TAPERED. BACF3T02F12-10 1 1 1 1 1 1 FILLER, TAPERED BACR15BB6D6C 40 40 40 40 40 40 RIVET, UNIVERSAL HD (e)
BACR15BB6D7C 7 7 7 7 7 7 RIVET, UNIVERSAL HD (e)
BACR15BB8AD5C 2 2 2 2 2 2 RIVET, UNIVERSAL HD (e) Group 3, 4, 5, 6, 9 and 10 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -6 -5 -4 -3 -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 100 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACS40R010A025P 1 1 1 1 1 1 SHIM, LAMINATED BACW10BN31AP 10 10 10 10 10 10 WASHER, PLAIN BACW10BN3AP 12 12 12 12 12 12 WASHER BACW10BN41AP 10 10 10 10 10 10 WASHER, COUNTERSUNK, OVERSIZE BACW10BN42AP 86 86 86 86 86 86 WASHER, COUNTERSUNK, OVERSIZE BACW10BN4AP 6 6 6 6 6 6 WASHER, PLAIN BACW10BN5AP 8 8 8 8 8 8 WASHER, COUNTERSUNK, OVERSIZEBACW10CA104CC 19 19 19 19 19 19 WASHER, SELFALIGNBACW10CA104CV 18 18 18 18 18 18 WASHER, SELFALIGNBACW10CA104PV 1 1 1 1 1 1 WASHER, SELFALIGN BACW10CA5CC 8 8 8 8 8 8 WASHERBACW10CA5PV 8 8 8 8 8 8 WASHER, SELFALIGN (a) For Group 5 and 10 airplanes. (b) For Group 6 airplanes. (c) For Group 9 airplanes where the S-18A Chord thickness is 0.33 inches. (d) For Group 3 and 4 airplanes. (e) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Boeing Document D-590 and Boeing Drawing 65-88700 are used to determine the part numbers used as substitutes. Group 1 and 2 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -10 -9 -8 -7**  65C38642-7 . . . - S-18A REPAIR (a) 65C38642-8 . . - . S-18A REPAIR (a) 65C38642-9 . - . . S-18A REPAIR (b) 65C38642-10 - . . . S-18A REPAIR (b) Group 3, 4, 5, 6, 9 and 10 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -6 -5 -4 -3 -2 -1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 101 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

65-48654-82 2 2 2 2 FILLER 65-48654-84 3 3 3 3 FILLER 65C37277-11 1 1 1 1 FILLER-TAPERED 65C37566-2 1 1 1 1 STRAP 65C37566-4 1 1 1 1 STRAP 65C37566-5 . . . 1 STRAP 65C37566-6 . . 1 . STRAP 65C37566-7 . 1 . . STRAP 65C37566-8 1 . . . STRAP 65C37566-17 1 1 1 1 STRAP S-18A OUTBD CHORD REPAIR, STA 727, KIT 69-78767-7 . 1 . 1 ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78767-8 1 . 1 . ATTACH ANGLE - AFT WING BODY FAIRING, STA 727 + 2.38 69-78768-4 1 1 1 1 WEB - AFT WING BODY FAIRING, STA 727 + 2.38 69-78769-5 . 1 . 1 ANGLE 69-78769-6 1 . 1 . ANGLE 69-78769-9 . 1 . 1 STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.3869-78770-3 . 1 . 1 STRAPEXTERNAL, STA 72769-78770-4 1 . 1 . STRAPEXTERNAL, STA 727 69-78773-1 1 1 1 1 FILLER-FLAT 69-78773-7 1 1 1 1 FILLER-TAPERED 69-78773-9 1 1 1 1 FILLER Group 1 and 2 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -10 -9 -8 -7** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 102 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

69-78769-10 1 . 1 . STIFFENER - AFT WING BODY FAIRING, STA 727 + 2.38 69-78773-16 1 1 1 1 FILLER DETAILS BACB30MB10A16 2 2 2 2 BOLT, PROTRUDING HD (c)
BACB30MB10A17 4 4 4 4 BOLT, PROTRUDING HD (c)
BACB30MB10A19 1 1 2 2 BOLT, HEX DRIVE (c) BACB30MB10A20 1 1 . . BOLT, PROTRUDING HD (c)
BACB30MY8K10Y . . 8 8 BOLT, PROTRUDING HD (c)
BACB30MY8K11X 1 1 2 2 BOLT, PROTRUDING HD (c)
BACB30MY8K11Y 1 1 4 4 BOLT, PROTRUDING HD (c)
BACB30MY8K12X . . 1 1 BOLT, PROTRUDING HD (c)
BACB30MY8K12Y 4 4 12 12 BOLT, PROTRUDING HD (c)
BACB30MY8K13Y 4 4 8 8 BOLT, PROTRUDING HD (c)
BACB30MY8K14X 1 1 . . BOLT, PROTRUDING HD (c)
BACB30MY8K14Y 12 12 4 4 BOLT, PROTRUDING HD (c)
BACB30MY8K15Y 5 5 2 2 BOLT, PROTRUDING HD (c)
BACB30MY8K16X 1 1 . . BOLT, PROTRUDING HD (c)
BACB30MY8K16Y 8 8 . . BOLT, PROTRUDING HD (c)
BACB30MY8K17Y 3 3 . . BOLT, PROTRUDING HD (c)
BACB30MY8K19Y 1 1 1 1 BOLT, PROTRUDING HD (c)
BACB30MY8K5Y 3 3 3 3 BOLT, PROTRUDING HD (c) Group 1 and 2 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -10 -9 -8 -7** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 103 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACB30MY8K6X 1 1 1 1 BOLT, PROTRUDING HD (c)
BACB30MY8K7X 5 5 1 1 BOLT, PROTRUDING HD (c)
BACB30MY8K7Y 28 28 28 28 BOLT, PROTRUDING HD (c)
BACB30MY8K8X 6 6 6 6 BOLT, PROTRUDING HD (c)
BACB30MY8K8Y 6 6 6 6 BOLT, PROTRUDING HD (c)
BACB30MY8K9Y 4 4 3 3 BOLT, PROTRUDING HD (c)
BACB30NX6K3 7 7 7 7 BOLT, PROTRUDING HD (c)
BACB30NX6K4 3 3 3 3 BOLT, PROTRUDING HD (c)
BACB30NX6K4X 9 9 9 9 BOLT, PROTRUDING HD (c)
BACB30NX6K5X 1 1 1 1 BOLT, PROTRUDING HD (c)
BACB30NX8K7 5 5 5 5 BOLT, HEX DRIVE (c) BACB30YP6K5 2 2 2 2 BOLT, 100 DEG HEX DR (c)
BACB30YP8K5 1 1 1 1 BOLT, 100 DEG HEX DR (c)

BACC30BH10 8 8 8 8 COLLAR BACC30BH6 10 10 10 10 COLLAR BACC30BH8 5 5 5 5 COLLAR BACC30BL6 2 2 2 2 COLLAR BACC30BL8 1 1 1 1 COLLAR BACC30M6 10 10 10 10 COLLAR BACC30M8 11 11 11 11 COLLAR BACC30R8 86 86 86 86 COLLAR BACF3F009P010NN 1 1 1 1 FILLER BACF3F010A030BN 1 1 1 1 FILLER, FLAT BACF3F024A166BN 1 1 1 1 FILLER, FLAT BACF3T01R30-10 1 1 1 1 FILLER, TAPERED. BACF3T01R38-10 1 1 1 1 FILLER, TAPERED BACF3T02F12-10 1 1 1 1 FILLER, TAPERED Group 1 and 2 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -10 -9 -8 -7** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 104 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

BACR15BB6D6C 40 40 40 40 RIVET, UNIVERSAL HD (c)
BACR15BB6D7C 7 7 7 7 RIVET, UNIVERSAL HD (c)
BACR15BB8AD5C 2 2 2 2 RIVET, UNIVERSAL HD (c)
BACW10BN31AP 10 10 10 10 WASHER, PLAIN BACW10BN3AP 12 12 12 12 WASHER BACW10BN41AP 10 10 10 10 WASHER, COUNTERSUNK, OVERSIZE BACW10BN42AP 86 86 86 86 WASHER, COUNTERSUNK, OVERSIZE BACW10BN4AP 6 6 6 6 WASHER, PLAIN BACW10BN5AP 8 8 8 8 WASHER, COUNTERSUNK, OVERSIZEBACW10CA104CC 25 25 25 25 WASHER, SELFALIGNBACW10CA104CV 24 24 24 24 WASHER, SELFALIGNBACW10CA104PV 1 1 1 1 WASHER, SELFALIGN BACW10CA5CC 8 8 8 8 WASHERBACW10CA5PV 8 8 8 8 WASHER, SELFALIGN (a) For Group 1 airplanes. (b) For Group 2 airplanes. (c) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. Boeing Document D-590 and Boeing Drawing 65-88700 are used to determine the part numbers used as substitutes. Group 1 and 2 **Kit 65C38642 - S-18A Chord Repair**

**New Part Number QTY**  **Name Notes -10 -9 -8 -7** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 105 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2. Parts and Materials Supplied by the Operator: a. Parts and Materials Supplied by the Operator for the STA 727 Frame Outboard Chord Time-Limited Repair: The table that follows shows the parts necessary at each installation. Groups 1 and 2, Configurations 1 and 4: **Part 65C38643**

**New Part Number QTY Name Notes** 65C38643-1 1 Shear Beam Web, Left Side (a) (b) (c) 65C38643-2 1 Shear Beam Web, Right Side (a) (b) (c) (a) Discard the existing part. (b) This part is not used in production. (c) This part is required for the replacement of the STA 727 Frame Outboard Chord Time-Limited Repair. Groups 3 through 9, Configurations 1 and 4: **Part 69-78347**

**New Part Number QTY Name Notes** 69-78347-1 1 Shear Beam Web, Left Side (a) (b) (c) 69-78347-2 1 Shear Beam Web, Right Side (a) (b) (c) (a) Discard the existing part. (b) This part is not used in production. (c) This part is required for the replacement of the STA 727 Frame Outboard Chord Time-Limited Repair.

**Part Number / Specification QTY Name Notes** BMS 5-95 Type I or II, Class B1/2 or B2. 16 Ounces Sealant (a)
BMS 10-11, Type 1 16 Ounces Primer (a) Type 2, Class A 8 Ounces Chemical Conversion Coating (b) AND10134-2008 x 20.8 inches, 7075-T6 or equivalent 1 Frame Repair Angle
1.25 x 4.25 x 0.032 inch 1 Shim A (c) 1.25 x 6 x 0.18 inch 1 Repair Strap (c) 1.2 x 1.4 x 0.14 inch 1 Filler A (c) (d) 8.2 x 1.4 x 0.202 inch 1 Filler B (c) (e) 8.2 x 4.25 x 0.15 inch 1 Shear Beam Repair Angle (f) 2.1 x 11.4 x 0.18 inch 1 Shim B (c)June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 106 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

1.2 x 8.7 x 0.18 inch 1 Shim C (c) 6.9 x 1.9 x 0.09 inch 1 Filler (Tapered) (c) BACB30MB8A( ) 70 Bolt (g) (h) (i) (m) BACB30FN8A( ) 1 Bolt (g) (i) (k) BACC30BH8 70 Collar (j) (m) BACC30M8 1 Collar (l) BACR15BA6D( )C 8 Rivet (g) (i) BACR15BB6D( )C OR BACR15FT6D( )C 8 Rivet (g) (i)

BACB30ZB4-6 3 Bolt (g) (n) BACB30ZB4-7 2 Bolt (g) (n) BACB30ZB4-8 1 Bolt (g) (n) NAS1149D0463H 4 Washer NAS679A4W 4 Nut (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to Boeing Standard Overhaul Practices Manual 20-43-03 or 737 Structural Repair Manual, Chapter 51, for material sources. (c) Fabricate from 7075-T6 Aluminum Alloy Sheet as shown in Figure 17. (d) If shear beam flange thickness is 0.125 inches, make Filler A 0.125 inch thick. (e) If shear beam thickness is 0.125 inches, make Filler B 0.217 inch thick. (f) Fabricate from 7075-T0 Aluminum Alloy Sheet as shown in Figure 17. (g) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (h) If 1/64 oversize is required, use BACB30MC( )A( ) bolts. If 1/32 oversize is required, use BACB30MD( )A( ) bolts. (i) Fastener length determined on installation. (j) If a 1/32 oversize bolt is required, use BACC30AC( ) collar. (k) If 1/64 oversize is required, use BACB30FQ( )A( ) bolts. If 1/32 oversize is required, use BACB30KF( )A( ) bolts. (l) If a 1/32 oversize bolt is required, use BACC30R( ) collar. (m) There are more parts than are required. (n) A total of 4 BACB30ZB4-( ) bolts are required for installation. **Part Number / Specification QTY Name Notes**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 107 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** b. Parts and Materials Supplied by the Operator for the replacement of the STA 727 Frame Outboard Chord Time-Limited Repair: The table that follows shows the parts necessary at each installation. **Part Number / Specification QTY Name Notes** BMS 5-95 Type I or II, Class B1/2 or B2. 16 Ounces Sealant (a)
BMS 10-11, Type 1 16 Ounces Primer (a) Type 2, Class A 8 Ounces Chemical Conversion Coating (b) 1.2 x 1.4 x inch 1 Filler A (c) (d) 1 x 6 x 0.15 inch 1 Filler B (c) (e) BACB30MB8A( ) 60 Bolt (f) (g) (h) (l) BACB30FN8A( ) 1 Bolt (f) (j) (k) BACC30BH8 60 Collar (i) (l) BACC30M8 1 Collar (k) BACR15BA6D( )C 8 Rivet (f) (h) BACR15BB6D( )C OR BACR15FT6D( )C 8 Rivet (f) (h)

BACB30ZB4-6 3 Bolt (f) (m) BACB30ZB4-7 2 Bolt (f) (m) BACB30ZB4-8 1 Bolt (f) (m) NAS1149D0463H 4 Washer NAS679A4W 4 Nut (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to Boeing Standard Overhaul Practices Manual 20-43-03 or 737 Structural Repair Manual, Chapter 51, for material sources. (c) Fabricate from 7075-T6 Aluminum Alloy Sheet as shown in Figure 20. (d) Thickness to match existing WL 190 stiffener. Target thickness is 0.156 or 0.125 inches. (e) Part is longer than required. (f) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (g) If 1/64 oversize is required, use BACB30MC( )A( ) bolts. If 1/32 oversize is required, use BACB30MD( )A( ) bolts. (h) Fastener length determined on installation. (i) If a 1/32 oversize bolt is required, use BACC30AC( ) collar. (j) If 1/64 oversize is required, use BACB30FQ( )A( ) bolts. If 1/32 oversize is required, use BACB30KF( )A( ) bolts. (k) If a 1/32 oversize bolt is required, use BACC30R( ) collar. (l) There are more parts than are required. (m) A total of 4 BACB30ZB4-( ) bolts are required for installation.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 108 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** c. Parts and Materials Supplied by the Operator for the replacement of fasteners after open hole HFEC inspection (Figure 10): The table that follows shows the parts necessary for each airplane.

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. Also, maintenance and overhaul tools in manuals shown in Paragraph I.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available. **Part Number / Specification QTY Name Notes** BMS 5-95 Type I or II, Class B1/2 or B2. 2 Ounces Sealant (a)
BACB30MB8A( ) (Steel) OR BACB30NX8K( ) (Titanium) 8 Bolt (b) (c) (d) (e)

BACC30BH8 8 Collar (f) (a) See the Qualified Products List at the end of the Boeing Material Specification (BMS) for supplier data. (b) Refer to 737 Structural Repair Manual Chapter 51 for alternative fasteners. (c) Steel bolts only - If 1/64 oversize is required, use BACB30MC8A( ) bolts. If 1/32 oversize is required, use BACB30MD8A( ) bolts. If 3/64 oversize is required, use BACB30ME8A( ) bolts. (d) Titanium bolts only - If 1/64 oversize is required, use BACB30NX8K( )X bolts. If 1/32 oversize is required, use BACB30NX8K( )Y bolts. (e) Fastener length determined on installation. (f) If a 1/32 oversize bolt is required, use BACC30AC8 collar. If a 3/64 oversize bolt is required use BACC30U8 collar (for steel bolts only).June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 109 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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. Unless shown differently, these dimensions and tolerances are used: — Linear dimensions are in inches — Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch. — Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch — Angular tolerance is plus or minus 2 degrees — Hole dimensions for standard solid rivets are given in 737 Structural Repair Manual, Chapter 51 — Torque limits to tighten nuts and bolts are given in 737 Structural Repair Manual, Chapter 51 — Edge margins for fasteners are given in 737 Structural Repair Manual, Chapter 51 4. For approved fastener substitutions, refer to 737 Structural Repair Manual, Chapter 51 or refer to Boeing D-590 Supersession List for standard parts. 5. If the length of fasteners specified in this service bulletin do not meet the installation standards, fasteners of the same specification, or an approved substitute, one grip length longer or shorter may be used. 6. Fastener installation is given in 737 Structural Repair Manual Chapter 51. Hex drive bolts and lock bolts may be oversized by up to 1/32 inch diameter, unless stated otherwise, while maintaining edge margin requirements. 7. All Hex drive bolts, lock bolts and bolts unless otherwise specified shall be installed wet with BMS5-95. Rivets shall be installed dry. Install hex drive bolts, lock bolts and bolts in transition fit holes or close ream fit holes for steel parts. 8. Shim all gaps greater than 0.01 inch up to a max of 0.04 inch prior to fastener installation unless otherwise stated. 9. 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.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 110 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** 10. 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.
**B. WORK INSTRUCTIONS**
**PART 1 - FLIGHT SAFETY INSPECTION PROGRAM**

1. **Access** Groups 1 through 3, Configurations 1, 3 and 4; Groups 4 through 11, Configurations 1 and 4: a. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation.
b. Get access to the inboard side of the frame at STA 727 from inside the wheel well. On the left side, at the operators option for more access, disconnect the connectors for the gauge and the detonator on the aft fire bottle as given in 737-100/200 AMM 26-21-11 or 737-300/ 400/500 AMM 26-21-11.

2. **Auxiliary Chord Inspection** Groups 1 through 3, Configurations 1, 3 and 4; Groups 4 through 11, Configurations 1 and 4: Do the inspection that follows at the threshold specified in Paragraph 1.E., Compliance, Table 5. a. Groups 1 through 3, Configuration 3: Do the internal detailed inspection and eddy current inspection of the STA 727 auxiliary chord radius shown in Figure 11. b. Groups 1 through 3, Configuration 4: Do the internal detailed inspection and eddy current inspection of the STA 727 auxiliary chord radius shown in Figure 12. c. Groups 1 through 3, Configuration 1; Groups 4 through 11, Configurations 1 and 4: Do the internal detailed inspection and eddy current inspection of the STA 727 auxiliary chord radius shown in Figure 24. d. If cracks are found, repair before further flight. Contact Boeing for repair data.
**NOTE:** A local repair will be provided to address the STA 727 frame auxiliary chord cracks.

3. **STA 727 Frame Outboard Chord Inspection** Groups 1 through 11, Configurations 1 and 4: Do the inspections that follow at the thresholds specified in Paragraph 1.E., Compliance, Table 2 or 3 as applicable. a. Do the external ultrasonic inspection of the STA 727 frame outboard chord forward flange as shown in Figure 7.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 111 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** b. Groups 1 through 11, Configuration 1: Do the external (wheel well) eddy current inspection of the replaced STA 727 frame outboard chord forward flange shown in Figure 8. c. Groups 1 through 11, Configuration 4: Do the external (wheel well) surface HFEC inspection of the STA 727 frame outboard chord forward flange as shown in Figure 9.
**CAUTION:** MAKE SURE FASTENER HOLES ARE ROUND BEFORE PERFORMING THE FIGURE 10 INSPECTIONS. d. Do the open hole eddy current inspection of the STA 727 frame outboard chord forward flange shown in Figure 10.
**NOTE:** The inspection provided in Figure 10 inspects for cracks in the aluminum STA 727 frame chord. Inspection of steel parts with this inspection procedure may produce false positive crack indications. This service bulletin does not require the inspection of the steel repair doubler used for short edge margin repair for Group 10 and Group 11 airplane.
**NOTE:** When performing the open hole eddy current inspections of the STA 727 frame outboard chord shown in Figure 10, it is recommended to minimize the growth of the fastener hole diameter when inspecting the hole or installing a fastener. Larger fastener holes may impact future inspections and the accomplishment of PART 6 - STA 727 Frame Outboard Chord Preventive Modification.
**CAUTION:** THE PART 4 - STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR IS LIMITED TO CRACKS THAT EXTEND FROM THE FORWARD EDGE OF THE CHORD, OR FROM THE FASTENER HOLE, BUT DO NOT EXTEND PAST THE SECOND FASTENER HOLE AFT. CRACKS NOT MEETING THIS DESCRIPTION MUST BE REPAIRED BY PART 3 - STA 727 FRAME OUTBOARD CHORD REPAIR. e. If cracks are found, repair before further flight as shown in PART 3 - STA 727 Frame Outboard Chord Repair or PART 4 - STA 727 Frame Outboard Chord Time-Limited Repair. If the repairs shown in PART 3 or PART 4 cannot be installed, contact Boeing for repair data. If a PART 3 repair is installed, inspections are still required per Compliance Table 3. If a PART 3 repair is installed along with a PART 6 modification, an inspection may be required per Compliance Table 4. If a PART 4 repair is installed then replacement is required per Compliance Table 6. Refer to Paragraph 1.E., Compliance, Table 3 or 4 or 6 as applicable. (1) Groups 1 through 9, Configurations 1 and 4: Repair as shown in PART 3 - STA 727 Frame Outboard Chord Repair or PART 4 - STA 727 Frame Outboard Chord Time-Limited Repair. If the repairs shown in PART 3 or PART 4 cannot be installed, contact Boeing for repair data. If a PART 3 repair is installed, inspections are still required per Compliance Table 3. If a PART 3 repair is installed along with a PART 6 modification, an inspection may be required per Compliance Table 4. If a PART 4 repair is installed then replacement is required per Compliance Table 6. Refer to Paragraph 1.E., Compliance, Table 3 or 4 or 6 as applicable. (2) Groups 10 and 11, Configurations 1 and 4: Contact Boeing for repair data.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 112 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** f. Groups 1 through 9, Configurations 1 and 4: If no cracks are found, put the airplane back to a serviceable condition or modify as shown in PART 6 - STA 727 Frame Outboard Chord Preventive Modification. If the modification is not installed, repeat the PART 1 inspections at the time specified in Paragraph 1.E., Compliance, Table 2 or 3 as applicable. If a STA 727 frame outboard chord interim modification is installed, do the inspections in PART 8 - STA 727 Frame Outboard Chord Interim Modification at the time specified in Paragraph 1.E., Compliance, Table 4. If a STA 727 frame outboard chord permanent modification is installed, inspections of the STA 727 frame outboard chord are terminated. g. Groups 10 and 11, Configurations 1 and 4: If no cracks are found, put the airplane back to a serviceable condition or contact Boeing for instructions to install a STA 727 Frame Outboard Chord Preventive Modification. If the modification is not installed, repeat the PART 1 inspections at the time specified in Paragraph 1.E., Compliance, Table 2 or 3 as applicable.

4. **Close Access** Groups 1 through 3, Configurations 1, 3 and 4, Groups 4 through 11, Configurations 1 and 4: a. If disconnected in Step 1. b, install the connectors for the gauge and the detonator on the aft fire bottle as given in 737-100/200 AMM 26-21-11 or 737-300/400/500 AMM 26-21-11. b. If removed in Step 1. a, install the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. c. Return the airplane to a serviceable condition.
**PART 2 - ECONOMIC INSPECTION PROGRAM**

1. **Access** Groups 1 through 6, 9 and 10:
**NOTE:** This inspection program looks for cracks in the stringer (S)-18A outboard chord where the chord thickness is 0.20 or 0.33 inches thick at STA 727. Group 9: This inspection program applies to one side of the airplane only where the S-18A Outboard Chord has a thickness of 0.33 inch at STA 727. The S-18A Outboard Chord is 0.33 inch thick on the left side of line numbers 2938 and 2940 and on the right side of line number 2942. a. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation.
b. Get access to the inboard side of the frame at STA 727 from inside the wheel well. On the left side, at the operators option for more access, disconnect the connectors for the gauge and the detonator on the aft fire bottle as given in 737-100/200 AMM 26-21-11 or 737-300/ 400/500 AMM 26-21-11.

2. **Stringer 18A Outboard Chord Inspection**June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 113 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** Group 1 through 6, 9 and 10: Do the inspections that follow at the thresholds specified in the Compliance section. a. Group 1: Do the external Detailed Inspection and the Eddy Current Inspection of the S-18A outboard chord as shown in Figure 13. b. Group 2; Group 3; Group 4; Group 5; Group 6; Group 9; Group 10: Do the external Detailed Inspection and the Eddy Current Inspection of the S-18A outboard chord as shown in Figure 14. c. Group 1; Group 2; Group 3; Group 4; Group 5; Group 6; Group 9: If cracks are found, repair before further flight as shown in PART 5 - S-18A Outboard Chord Repair. If the repairs shown in PART 5 cannot be installed, contact Boeing for repair data. If a S-18A repair is installed, S-18A outboard chord inspections are terminated. d. Group 10: If cracks are found, repair before further flight. Contact Boeing for repair data. e. Group 1; Group 2; Group 3; Group 4; Group 5; Group 6; Group 9: If no cracks are found, put the airplane back to a serviceable condition or modify as shown in PART 7 - S-18A Outboard Chord Preventive Modification. If the S-18A outboard chord modification is not installed, repeat the PART 2 inspections at the time specified in Paragraph 1.E., Compliance, Table 1. If a S-18A outboard chord modification is installed, inspections of the S-18A outboard chord are terminated. f. Group 10: If no cracks are found, put the airplane back to a serviceable condition or contact Boeing to install a S-18A Outboard Chord Preventive Modification. If the S-18A outboard chord modification is not installed, repeat the PART 2 inspections at the time specified in Paragraph 1.E., Compliance, Table 1.

3. **Close Access** Groups 1 through 6, 9 and 10: a. If disconnected in Step 1. b, install the connectors for the gauge and the detonator on the aft fire bottle as given in 737-100/200 AMM 26-21-11 or 737-300/400/500 AMM 26-21-11. b. If removed in Step 1. a, install the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. c. Return the airplane to a serviceable condition.
**PART 3 - STA 727 FRAME OUTBOARD CHORD REPAIR**

1. **Prepare Airplane For Maintenance** Groups 1-9
**NOTE:** STA 727 Frame Outboard Chord Repair is not available for Groups 10 and 11, contact Boeing for repair data. a. Support the airplane in the jig position as given in 737-100/200 SRM 51-50-1 or 737-300 SRM 51-50-02 or 737-400 SRM 51-50-02 or 737-500 SRM 51-50-02. If support cradles are used, do not install the cradle at STA 727 to allow access for repair.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 114 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2. **STA 727 Frame Outboard Chord Repair** a. As of the release date of Revision 2 of this service bulletin, replace the STA 727 frame outboard chord as given in Boeing Service Bulletin 737-53-1088 Revision 1, dated May 25, 2006. If the frame outboard chord was replaced and modified as given in the initial release of Boeing Service Bulletin 737-53-1088, no more work is necessary.
**NOTE:** 1. When performing the PART 3 - STA 727 frame outboard chord repair, it is recommended to keep expansion of the fastener holes common to the S-18A outboard chord to a minimum. Larger diameter fastener holes may impact future inspections and the accomplishment of PART 6 - STA 727 Frame Outboard Chord Preventive Modification. 2. Boeing recommends that the PART 6 - STA 727 frame outboard chord preventive modification and PART 7 - S-18A outboard chord preventive modification be installed with the replaced STA 727 frame outboard chord. Operators may install the PART 6 - STA 727 frame outboard chord preventive modification and PART 7 - S-18A outboard chord preventive modification at a later time, however inspections may be required and increased installation costs will be incurred. 3. The PART 3 - STA 727 frame outboard chord repair can be accomplished at the same time on both the left and right sides of the airplane. 4. If the Part 6 - STA 727 Frame Outboard Chord Preventive Modification, or the Part 5 - S-18A Outboard Chord Repair or the Part 7 - S-18A Outboard Chord Preventive Modification is being accomplished at the same time as a STA 727 frame outboard chord replacement using instructions from Boeing Service Bulletin 737-53-1088 Revision 1, dated May 25, 2006, use the fasteners as specified in this service bulletin at common locations.
**PART 4 - STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR**

1. **Prepare Airplane For Maintenance**
**NOTE:** The Time-Limited Repair is intended to provide the operator with options if a replacement chord is not available in a timely manner. Boeing recommends that a replacement chord be used whenever possible. The Time-Limited Repair will result in additional work and future chord replacement.
**CAUTION:** THE INSTALLATION OF THIS TIME-LIMITED REPAIR USES NESTED ANGLES AND PLATES THAT MAY RESULT IN LOW EDGE MARGINS AND INSUFFICIENT RADIUS CLEARANCE FOR FASTENER INSTALLATIONS. CHECK EXISTING FASTENER LOCATIONS PRIOR TO PROCEEDING WITHJune 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 115 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
THIS INSTALLATION.
THE PART 4 - STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR IS LIMITED TO CRACKS THAT EXTEND FROM THE FORWARD EDGE OF THE CHORD, OR FROM THE FASTENER HOLE, BUT DO NOT EXTEND PAST THE SECOND FASTENER HOLE AFT. THE EXTENT OF THE CRACK WILL NOT BE KNOWN UNTIL AFTER THE EXISTING STRUCTURE IS TRIMMED OR REMOVED. CRACKS NOT MEETING THIS DESCRIPTION MUST BE REPAIRED BY PART 3 - STA 727 FRAME OUTBOARD CHORD REPAIR. FOR AIRPLANES WITH A SHEAR BEAM REPAIRED PER S/B 737-53-1170, THE FRAME CHORD MUST BE REPAIRED USING PART 3 - STA 727 FRAME OUTBOARD CHORD REPAIR. a. If a repair was previously installed per drawing 65C36009 to address short edge margins along S-18A and the existing repair is common to STA 727, contact Boeing for repair data. b. Support the airplane in the jig position as given in 737-100/200 SRM 51-50-1 or 737-300 SRM 51-50-02 or 737-400 SRM 51-50-02 or 737-500 SRM 51-50-02. If support cradles are used, do not install the cradle at STA 727 to allow access for repair. c. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation. d. Remove the following equipment from the wheel well and cargo compartments as necessary for access to the STA 727 Frame Outboard Chord.

2. **Stringer 18A and STA 727 Outboard Chord Inspection** a. Do a General Visual Inspection to identify the quantity of fasteners attaching the stringer S-18A to the STA 727 frame outboard chord forward flange. If four fasteners are identified then proceed with the time-limited repair. If less than four fasteners are identified, contact Boeing for repair data. b. Do a Detailed Inspection of the exposed STA 727 outboard chord forward flange for corrosion. **Equipment 737-100/-200 AMM Subject 737-300/-400/-500 AMM Subject** Wing-to-Body Fairing 53-51-21 53-51-21 Fire Extinguisher Bottles 26-21-11 26-21-11 Cargo Liner 25-52-123 25-52-73 Cargo Floor Panel 25-52-51 25-52-51 Cargo Bulkhead Panel 25-52-131 25-52-81 Auxiliary Fuel Tank (if installed) 53-23-1 53-23-12 Insulation Blankets 25-52-141 25-52-91 Flap Right Angle Gearbox 27-51-261 27-51-67June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 116 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** (1) If corrosion is found, remove the corrosion as shown in 737-100/200 SRM 51-10-6 or 737-300 SRM 51-10-02 or 737-400 SRM 51-10-02 or 737-500 SRM 51-10-02. c. On the forward side of the bulkhead at STA 727, locate the horizontal stiffener at approximately Water Line (WL) 190. Trim the horizontal stiffener and S-18A shear beam web as shown in Figure 15 to allow for the installation of the repair angle.
**NOTE:** 1. Boeing Service Bulletin 737-53-1066 and 737-53-1170 provide a repair or a preventive modification that installs sheet aluminum components common to the S-18A shear beam and the horizontal stiffener at approximately WL 190. 2. This repair is limited to cracks that extend from the forward edge of the chord, or from the forward fastener hole, but do not extend past the second fastener hole aft. The extent of the crack will not be known until after existing structure is trimmed or removed. Cracks not meeting this description must be repaired by PART 3 - STA 727 Frame Outboard Chord Repair. d. Do a High Frequency Eddy Current (HFEC) inspection of the inboard surface of the STA 727 frame chord to determine the location of the end of the crack as shown in Figure 16. As an option to trimming the shear beam flange, remove the shear beam web from approximately STA 711 to STA 727 to provide access to the inboard surface of the STA 727 frame outboard chord forward flange.
**NOTE:** The shear beam web removal option will allow inspection of the frame chord without trimming the shear beam. If the STA 727 frame chord outboard flange is cracked beyond allowable limits for the time-limited repair, this option will allow re-use of the shear beam web with a STA 727 frame chord replacement. (1) If the crack extends from the forward edge of the chord, or from the forward fastener hole, but does not extend past the second fastener hole aft, then stop drill the crack using the procedure given in 737-100/200 SRM 51-10-1 or 737-300 SRM 51-10-02 or 737-400 SRM 51-10-02 or 737-500 SRM 51-10-02. Use 737 NDT Part 6 51-00-00 Figure 16 for open hole inspections using the 0.020 notch standard. If the crack is contained within a fastener hole in the STA 727 frame outboard chord, the fastener hole is the stop drill hole, otherwise drill a new hole in the STA 727 frame outboard chord only, as described in the SRM. Existing fastener holes acting as a stop drill hole or a new stop drill hole must be inspected and have an insurance cut as described in the SRM. Contact Boeing if a new stop drill hole location is less than 1.2 stop drill hole diameters from existing holes. For both new and existing holes do the stop drill and insurance cut in the STA 727 frame outboard chord only.
**NOTE:** Do the stop drill and insurance cut of holes in the STA 727 frame outboard chord from the wheel well side. Protect the structure on the exit side of the hole from potential drill damage. (2) If the crack or stop drill hole extends past the second fastener hole aft of the forward edge of the chord, do PART 3 - STA 727 Frame Outboard Chord Repair. If the shear beam was optionally removed, reinstall it using the same size and type fasteners as removed unless stated differently in this service bulletin. Install hex drive and lock bolt fasteners in transition fit holes using BMS5-95.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 117 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** e. Make the repair parts as shown in Figure 17. f. Install the repair parts as shown in Figure 18. If the shear beam web was removed, reinstall the shear beam web using the same size and type fasteners as were removed. Install hex drive and lock bolt fasteners in transition fit holes with BMS5-95. Reinstall fasteners common to the repair parts as shown in Figure 18.
**NOTE:** 1. The repair angle replaces the forward splice angle of the STA 727 frame outboard chord if a chord replacement kit has been previously installed per Boeing Service Bulletin 737-53-1088. Use the existing fastener locations common to the area previously covered by the forward splice angle. Replace fasteners with the same size and type. Install hex drive and lock bolt fasteners in transition fit holes with BMS5-95. Install fasteners in new locations as shown in Figure 18. 2. When performing the STA 727 frame outboard chord Time-Limited repair, it is recommended to keep expansion of the fastener holes common to the S-18A outboard chord to a minimum. Larger diameter fastener holes may impact future inspections and the accomplishment of PART 6 - STA 727 Frame Outboard Chord Preventive Modification.

3. **Close Access** a. Install the equipment in the wheel well and cargo hold that was removed for access. b. At the time specified in Paragraph 1.E. Compliance Table 6, replace the STA 727 frame outboard chord as shown in PART 9: Replacement of the Time-limited Repair. c. Put the airplane back to a serviceable condition.
**PART 5 - STRINGER 18A OUTBOARD CHORD REPAIR**

1. **Prepare Airplane For Maintenance** Groups 1 through 6 and Group 9:
**NOTE:** Group 9: This repair only applies to one side of the airplane only where the S-18A Outboard Chord has a thickness of 0.33 inch at STA 727.
**NOTE:** S-18A repair is not available for Groups 10 and 11, contact Boeing for repair data. a. Support the airplane in the jig position as given in 737-100/200 SRM 51-50-1 or 737-300 SRM 51-50-02 or 737-400 SRM 51-50-02 or 737-500 SRM 51-50-02. If support cradles are used, do not install the cradle at STA 727 to allow access for repair. b. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 118 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** c. Remove the following equipment from the wheel well and cargo compartments as necessary for access to the STA 727 Frame Outboard Chord.

2. **Stringer 18A Outboard Chord Inspection** a. Do the inspection as shown in Figure 21 to identify the quantity of fasteners in the aft end of the S-18A outboard chord aft of the STA 727 frame outboard chord aft flange. If there are less than 15 fasteners in a single row, contact Boeing for repair data. b. Do the S-18A outboard chord repair as shown in drawing 65C38642.
**NOTE:** 1. Revision 1 and earlier versions of this service bulletin previously installed the S-18A outboard chord repair as shown in drawing 65C37565. Drawing 65C37565 is now superseded by drawing 65C38642. 2. When performing the PART 5 - S-18A Outboard Chord Repair, it is recommended to keep expansion of the fastener holes common to STA 727 frame outboard chord to a minimum when installing fasteners. Larger fastener hole diameters may impact future inspections and the accomplishment of PART 6 - STA 727 Frame Outboard Chord Preventive Modification. 3. Drawing 65C38642 provides repair procedures for airplanes with and without the PART 6 - STA 727 frame outboard chord preventive modification installed. 4. The S-18A repair parts can be purchased as a repair kit 65C38642, refer to Paragraph 2.A., Material - Price and Availability, or, as an option, the S-18A repair parts can be made by the operator. Refer to Drawing 65C38642. 5. The stringer S-18A repair installs new structure to replace most of the STA 727 fairing support structure that was removed.
3. **Close Access** a. Install the equipment that was removed for access. b. Put the airplane back to a serviceable condition. **Equipment 737-100/-200 AMM Subject 737-300/-400/-500 AMM Subject** Wing-to-Body Fairing 53-51-21 53-51-21 Fire Extinguisher Bottles 26-21-11 26-21-11 Cargo Liner 25-52-123 25-52-73 Cargo Floor Panel 25-52-51 25-52-51 Cargo Bulkhead Panel 25-52-131 25-52-81 Auxiliary Fuel Tank (if installed) 53-23-1 53-23-12 Insulation Blankets 25-52-141 25-52-91 Flap Right Angle Gearbox 27-51-261 27-51-67June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 119 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

**PART 6 - STA 727 FRAME OUTBOARD CHORD PREVENTIVE MODIFICATION**

1. **Access** Group 1 through 9
**NOTE:** 1. STA 727 frame outboard chord preventive modification is not available for Groups 10 and 11, contact Boeing for repair data. 2. When the Part 6 - STA 727 Frame Outboard Chord Preventive Modification, or the Part 5 - S-18A Outboard Chord Repair or the Part 7 - S-18A Outboard Chord Preventive Modification is being accomplished at the same time as a STA 727 frame outboard chord replacement using instructions from Boeing Service Bulletin 737-53-1088 Revision 1, dated May 25, 2006, use the fasteners as specified in this service bulletin at common locations. 3. These instructions provide a STA 727 frame outboard chord modification option to address specific edge margin conditions that result in follow-on inspections. 4. Boeing recommends that the PART 7 - S-18A outboard chord preventive modification be installed with the PART 6 - STA 727 frame outboard chord preventive modification. a. If a repair was previously installed per drawing 65C36009 to address short edge margins along S-18A and the existing repair is common to the locations to be impacted by the Part 6 Modification, contact Boeing for repair data. b. Support the airplane in the jig position as given in 737-100/200 SRM 51-50-1 or 737-300 SRM 51-50-02 or 737-400 SRM 51-50-02 or 737-500 SRM 51-50-02. If support cradles are used, do not install the cradle at STA 727 to allow access for the modification. c. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation. d. Remove the following equipment from the wheel well and cargo compartment as necessary for access to the STA 727 Frame Outboard Chord and the inboard side of S-18A between STA 709 and STA 727. **Equipment 737-100/-200 AMM Subject**  **737-300/-400/-500 AMM Subject**  Wing-to-Body Fairing 53-51-21 53-51-21 Fire Extinguisher Bottles 26-21-11 26-21-11 Cargo Liner 25-52-123 25-52-73 Cargo Floor Panel 25-52-51 25-52-51 Cargo Bulkhead Panel 25-52-131 25-52-81June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 120 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2. **STA 727 Frame Outboard Chord Forward and Aft Flange Inspection** a. Do a General Visual Inspection to identify the quantity of fasteners attaching the S-18A stringer to the STA 727 frame outboard chord forward flange. If four fasteners are identified then proceed with the preventive modification. If less than four fasteners are identified, contact Boeing for repair data. b. Do the inspection as shown in Figure 21 to identify the quantity of fasteners in the aft end of the S-18A outboard chord aft of the STA 727 frame outboard chord aft flange. If there are less than 15 fasteners in a single row, contact Boeing for repair data. c. Do a Detailed Inspection of the exposed STA 727 outboard chord forward flange for corrosion. (1) If corrosion is found, remove the corrosion as shown in 737-100/200 SRM 51-10-6 or 737-300 SRM 51-10-02 or 737-400 SRM 51-10-02 or 737-500 SRM 51-10-02.
**NOTE:** A corrosion inspection is not required when a STA 727 frame outboard chord is replaced and the STA 727 frame outboard chord preventive modification is installed at the same time. d. Remove fasteners as required for modification. e. Inspect for disbonding of the doublers from the skins of both the forward and aft skin panels using 737 NDT Manual Part 4, 51-40-00 Figure 1. Inspect the area that will be covered by the STA 727 frame outboard chord preventive modification strap. If disbonding is identified contact Boeing for repair data before further flight. f. Evaluate the existing condition of the fastener holes in the STA 727 frame outboard chord at the intersection of the S-18A outboard chord as shown below. (1) Measure the edge margin and inspect fastener holes for roundness at fastener locations in the STA 727 frame outboard chord forward flange common to the S-18A outboard chord as shown in Figure 22. (2) Do an open hole HFEC inspection of the 4 fastener holes in the STA 727 frame outboard chord forward flange as shown in Figure 10 using a 0.020 notch standard.
**NOTE:** The use of 0.02 inch notch standards in the open hole inspection may give false crack indications if holes are not clean or round. The holes can be oversized for clean-up within the limitations of tables 1 and 2 provided the appropriate insurance cut and edge margins are obtained. (3) Do an external ultrasonic inspection of the STA 727 frame outboard chord forward flange as shown in Figure 7. Auxiliary Fuel Tank (if installed) 53-23-1 53-23-11 Insulation Blankets 25-52-141 25-52-91 Flap Right Angle Gearbox 27-51-261 27-51-67 **Equipment 737-100/-200 AMM Subject**  **737-300/-400/-500 AMM Subject** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 121 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** (4) Groups 1 through 9, Configuration 4: From the wheel well, do a surface HFEC inspection of the STA 727 frame outboard chord forward flange as shown in Figure 9. (5) Groups 1 through 9, Configuration 1: From the wheel well, do the eddy current inspections (LFEC and HFEC) of the STA 727 frame outboard chord forward flange as shown in Figure 8. g. If cracks are found, repair before further flight as shown in PART 3 - STA 727 Frame Outboard Chord Repair or PART 4 - STA 727 Frame Outboard Chord Time-Limited Repair. If the repairs shown in PART 3 or PART 4 cannot be installed, contact Boeing for repair data. If a PART 3 or PART 4 repair is installed, inspections are still required. Refer to Paragraph 1.E., Compliance. h. If no cracks are found, then determine if a permanent modification, interim modification or a frame replacement should be accomplished. If the Edge Margin after insurance cut is 1.7 or greater (Table 1), then install a permanent modification. If the Edge Margin after insurance cut is less than 1.7 but greater than or equal to 1.5 (Table 2), then install an interim modification. If the edge margin is less than 1.5 then replace the 727 frame chord.
**NOTE:** 1. If the interim modification is installed, then a one-time post modification inspection will be required in accordance with Paragraph 1.E. Compliance, Table 4. 2. The chord replacement as given in this service bulletin installs a chord with extra edge material on the forward flange at stringer 18A. i. Install the applicable STA 727 frame outboard chord modification. Use drawing 65C37277 and the minimum fastener size required to meet the installation requirements specified in Table 1 or Table 2. Table 3 provides titanium fasteners and associated collars as equivalent to the steel fasteners provided in Table 1 or Table 2.
**NOTE:** 1. Make sure proper insurance cuts are taken as shown in Tables 1 and 2, after the HFEC hole probe inspection shows no crack indications. 2. Use repair washers as directed by drawing 65C37277 where existing countersink locations are covered by the modification strap. Table 1: Permanent Modification (Edge Margin greater than 1.7D) (a) **Starting Hole Size (Nominal +**  **Oversize) Minimum**  **Starting Edge Margin**  **(1.7D Final) Hole Diameter**  **Range for Hole Probe Inspection**  **(b) Final Close**  **Ream Hole Size For Insurance**  **Cut Fastener** 

1/4 0.53 0.2495 - 0.2661 0.3120 - 0.3130 BACB30MB10A* + BACC30BH10 1/4 + 1/64 0.53 0.2651 - 0.2661 0.3120 - 0.3130 BACB30MB10A* + BACC30BH10 1/4 + 1/32 0.56 0.2807 - 0.2817 0.3276 - 0.3286 BACB30MC10A* + BACC30BH10June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 122 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

1/4 + 3/64 0.58 0.2963 - 0.2973 0.3432 - 0.3442 BACB30MD10A* + BACC30AC10 5/16 0.61 0.312 - 0.313 0.3589 - 0.3599 BACB30ME10A* + BACC30U10 (a) Used on production or replaced STA 727 frame outboard chords. (b) 737 NDT Part 6, 51-00-00 Figure 16 with 0.020 notch standard.
Table 2: Interim Modif ication With Follow-on Inspections (Edge Margin greater than 1.5D but less than 1.7D) (a) **Starting Hole Size (Nominal +**  **Oversize) Minimum**  **Starting Edge Margin**  **(1.5D Final) Hole Diameter**  **Range for Hole Probe Inspection**  **(b) Final Close**  **Ream Hole Size For Insurance**  **Cut Fastener** 

1/4 0.47 0.2495 - 0.2661 0.3120 - 0.3130 BACB30MB10A* + BACC30BH10 1/4 + 1/64 0.47 0.2651 - 0.2661 0.3120 - 0.3130 BACB30MB10A* + BACC30BH10 1/4 + 1/32 0.49 0.2807 - 0.2817 0.3276 - 0.3286 BACB30MC10A* + BACC30BH10 1/4 + 3/64 0.52 0.2963 - 0.2973 0.3432 - 0.3442 BACB30MD10A* + BACC30AC10 5/16 0.54 0.312 - 0.313 0.3589 - 0.3599 BACB30ME10A* + BACC30U10 (a) Used on production or replaced STA 727 frame outboard chords. (b) 737 NDT Part 6, 51-00-00 Figure 16 with 0.020 notch standard.

Tab le 3: Titanium Equivalent Fasteners and Collars **Steel Fasteners + Collar**  **Titanium Fasteners + Collar**  BACB30MB*A* + BACC30BH* BACB30NX*K* + BACC30BH* BACB30MC*A* + BACC30BH* BACB30NX*K*X + BACC30BH* BACB30MD*A* + BACC30AC* BACB30NX*K*Y + BACC30AC* Table 1: Permanent Modification (Edge Margin greater than 1.7D) (a) **Starting Hole Size (Nominal +**  **Oversize) Minimum**  **Starting Edge Margin**  **(1.7D Final) Hole Diameter**  **Range for Hole Probe Inspection**  **(b) Final Close**  **Ream Hole Size For Insurance**  **Cut Fastener** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 123 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

**NOTE:** 1. Service Bulletin 737-53-1077 installs a repair patch at STA 727 and S-18A. If the repair patch is installed, then the 69-78773-10 filler is not needed. If necessary, install an additional filler forward of STA 727 to match the thickness of the repair patch. If necessary, also use a tapered filler forward of STA 727, same as the 69-78773-7 tapered filler, but with the thickness increased to match the repair patch. Keep the same taper ratio. 2. The preventive modification installs new structure to replace most of the STA 727 fairing support structure that was removed.
3. **Close Access** a. Install the equipment that was removed for access. b. Put the airplane back to a serviceable condition.
**PART 7 - STRINGER 18A OUTBOARD CHORD PREVENTIVE MODIFICATION** 

1. **Access** Group 1; Group 2; Group 3; Group 4; Group 5; Group 6; Group 9:
**NOTE:** 1. S-18A outboard chord preventive modification is not available for Groups 10 and 11, contact Boeing for repair data. 2. Boeing recommends that the PART 7 - S-18A outboard chord preventive modification be installed with the PART 6 - STA 727 frame outboard chord preventive modification. 3. Group 9: The PART 7 - S-18A outboard chord preventive modification only applies to one side of the airplane only where the S-18A Outboard Chord has a thickness of 0.33 inch at STA 727. a. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation. b. Remove the Wing-to-Body Fairings as necessary for access to the S-18A Outboard Chord as given in 737-100/200/300/400/500 AMM 53-51-21.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 124 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2. **Preventive Modification** a. Do the inspection as shown in Figure 21 to identify the quantity of fasteners in the aft end of the S-18A outboard chord aft of the STA 727 frame outboard chord aft flange. If there are less than 15 fasteners in a single row, contact Boeing for repair data. b. Group 1; Group 2: Do the S-18A outboard chord modification as specified in drawing 65C38491-1/-2.
**NOTE:** 1. The stringer S-18A preventive modification installs new structure to replace most of the STA 727 fairing support structure that was removed. 2. When performing the PART 7 - S-18A Outboard Chord Preventive Modification, it is recommended to keep expansion of the fastener holes common to the STA 727 frame outboard chord to a minimum when installing fasteners. Larger fastener hole diameters may impact future inspections and the accomplishment of PART 6 - STA 727 Frame Outboard Chord Preventive Modification. c. Group 3; Group 4; Group 5; Group 6; Group 9: Do the S-18A outboard chord modification as specified in drawing 65C37277.
**NOTE:** 1. The stringer S-18A preventive modification installs new structure to replace most of the STA 727 fairing support structure that was removed. 2. When performing the PART 7 - S-18A Outboard Chord Preventive Modification, it is recommended to keep expansion of the fastener holes common to the STA 727 frame outboard chord to a minimum when installing fasteners. Larger fastener hole diameters may impact future inspections and the accomplishment of PART 6 - STA 727 Frame Outboard Chord Preventive Modification.

3. **Close Access** a. Install the equipment that was removed for access. b. Put the airplane back to a serviceable condition.
**PART 8 - ONE TIME INSPECTION OF THE STA 727 FRAME OUTBOARD CHORD INTERIM MODIFICATION** 

1. **Access** a. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation.June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 125 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
b. Get access to the inboard side of the frame at STA 727 from inside the wheel well. On the left side, at the operators option for more access, disconnect the connectors for the gauge and the detonator on the aft fire bottle as given in 737-100/200 AMM 26-21-11 or 737-300/ 400/500 AMM 26-21-11.

2. **STA 727 Frame Outboard Chord Inspection** a. Do the inspections that follow at the thresholds specified in paragraph 1.E., Compliance, Table 4. b. At each fastener location with a frame chord edge margin greater than or equal to 1.5D and less than 1.7D do a one-time HFEC hole probe inspection of the STA 727 frame outboard chord as shown Figure 10. c. Replace hex drive fasteners and collars with the same size and type. If necessary, use 1/64 inch oversize. Install hex drive fasteners in a close ream fit at these locations with steel parts. Install wet with BMS5-95.
**NOTE:** Do not exceed 3/8 fastener diameter. If final edge margin with replacement fasteners will be less than 1.5D, contact Boeing.
3. **Close Access** a. Install and reconnect the equipment in the wheel well that was removed or disconnected for access. b. Put the airplane back to a serviceable condition.
**PART 9 - REPLACMENT OF THE TIME-LIMITED REPAIR**

1. **Access**
**NOTE:** Boeing recommends that the PART 6 - STA 727 frame outboard chord preventive modification and PART 7 - S-18A outboard chord preventive modification be installed at the same time as the PART 3 - STA 727 frame outboard chord replacement. Operators may do the PART 6 - STA 727 frame outboard chord preventive modification and PART 7 - S-18A outboard chord preventive modification at a later time, however inspections may be required and increased installation costs will be incurred. a. Fully extend the trailing edge flaps. Get access to the outboard side of the frame at STA 727 through the opening in the flap fairing. At the operators option, for more access, remove the fairing for the inboard track of the inboard flap as given in 737-100/200 AMM 27-51-141 or 737-300/400/500 AMM 27-51-32. Keep the fairing and all fasteners for installation. b. Remove the following equipment from the wheel well and cargo compartment as necessary for access to the STA 727 Frame Outboard Chord. **Equipment 737-100/-200 AMM Subject 737-300/-400/-500 AMM Subject** Wing-to-Body Fairing 53-51-21 53-51-21 Fire Extinguisher Bottles 26-21-11 26-21-11 Cargo Liner 25-52-123 25-52-73June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 126 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

2. **Removal of the Time Limited Repair** a. Remove the Time-Limited Repair as shown in Figure 19. b. Make new parts for the shear beam repair as shown in the Figure 20. c. Install PART 3 - STA 727 Frame Outboard Chord Repair using Figure 23 to remove and install a new S-18A shear beam web. Remove and replace the shear beam web aft section from approximately STA 711 to STA 727. Use the same size and type fasteners as removed. Install fasteners common to both the STA 727 frame outboard chord and the shear beam web at frame chord installation per instructions provided in Part 3. (1) Groups 1 and 2, Configurations 1 and 4: Replace the shear beam web using the new part 65C38643-1/-2. (2) Groups 3 through 9, Configurations 1 and 4: Replace the shear beam web using the new part 69-78347-1/-2. (3) For Airplane Line Number 3, contact Boeing for repair instructions.
3. **Close Access** a. Install the equipment that was removed for access. b. Put the airplane back to a serviceable condition. Cargo Floor Panel 25-52-51 25-52-51 Cargo Bulkhead Panel 25-52-131 25-52-81 Auxiliary Fuel Tank (if installed) 53-23-1 53-23-11 Insulation Blankets 25-52-141 25-52-91 Flap Right Angle Gearbox 27-51-261 27-51-67 **Equipment 737-100/-200 AMM Subject 737-300/-400/-500 AMM Subject FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 2**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 127 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 1: THIS FIGURE WAS DELETED AT REVISION 2**



### NOTE: REVISION 2 REMOVED FIGURE 1D39061

**(SHEET 1 OF 1) FIGURE 2: THIS FIGURE**  **WAS DELETED AT REVISION 2** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 128 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 2: THIS FIGURE WAS DELETED AT REVISION 2**



### NOTE: REVISION 2 REMOVED FIGURE 2D41118

**(SHEET 1 OF 1) FIGURE 3: THIS FIGURE WAS DELETED AT REVISION 2**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 129 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 3: THIS FIGURE WAS DELETED AT REVISION 2**



### NOTE: REVISION 2 REMOVED FIGURE 3D39063

**(SHEET 1 OF 1) FIGURE 4: THIS FIGURE**  **WAS DELETED AT REVISION 2** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 130 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 4: THIS FIGURE WAS DELETED AT REVISION 2**



### NOTE: REVISION 2 REMOVED FIGURE 4J74437

**(SHEET 1 OF 1) FIGURE 5: THIS FIGURE WAS DELETED AT REVISION 2**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 131 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 5: THIS FIGURE WAS DELETED AT REVISION 2**



### NOTE: REVISION 2 REMOVED FIGURE 5D39065

**(SHEET 1 OF 1) FIGURE 6: THIS FIGURE**  **WAS DELETED AT REVISION 2** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 132 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 6: THIS FIGURE WAS DELETED AT REVISION 2**



### NOTE: REVISION 2 REMOVED FIGURE 6D39067

**(SHEET 1 OF 1) FIGURE 7: EXTERNAL ULTRASONIC INSPECTION OF THE STA 727 FRAME OUTBOARD CHORD**  **FORWARD FLANGE - GROUPS 1 THROUGH 11, CONFIGURATIONS 1 AND 4.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 133 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 7: EXTERNAL ULTRASONIC INSPECTION OF THE STA 727 FRAME OUTBOARD CHORD FORWARD FLANGE - GROUPS 1 THRO**  **UGH 11, CONFIGURAT IONS 1 AND 4.** 

(WING-TO-BODY FAIRING NOT SHOWN) RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SEE AD39072

**(SHEET 1 OF 3) FIGURE 7: EXTERNAL ULTRASONIC INSPEC**  **TION OF THE STA 727 FRAME OUTBOARD CHORD FORWARD FLANGE - GROUPS 1 THROUG**  **H 11, CONFIGURATIONS 1 AND 4.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 134 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

INBD FWD STA 727 STA 727

FLANGE FORWARD FRAME SKIN AFT SKIN FORWARD

AREA INSPECTION SEE B



### A

BD40369 A FLAT STRAP) STRINGER 18A IS THE OUTER CHORD OF (ON MOST AIRPLANES STRINGER 18A

CRACK TYPICAL

VIEW LOOKING INBOARD STRUCTURE NOT SHOWN FOR CLARITY) (STRINGER 18A AND FAIRING SUPPORT 1

**(SHEET 2 OF 3) FIGURE 7: EXTERNAL ULTRASONIC INSPECTION OF THE STA 727 FRAME OUTBOARD CHORD**  **FORWARD FLANGE - GROUPS 1 THROUGH 11, CONFIGURATIONS 1 AND 4.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 135 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Frame Chord Forward Flange External Ultrasonic 737 NDT Part 4 Subject 53-10-01 (a) (b) For cracks
(a) An External Inspection is done from outside the airplane in the wheel well area. (b) Cracks can also be found between fasteners.

**(SHEET 3 OF 3) FIGURE 8: EDDY CURRENT INSPECTION - GROUPS 1 THROUGH 11, CONFIGURATION 1.**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 136 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT FIGURE 8: EDDY CURRENT INSPECTION - GROUPS 1 THROUGH 11, CONFIGURATION 1.** 

727 STA

FWD

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) VIEW FROM INSIDE THE WHEEL WELL SEE A 1D39253 SPLICE STRAP. OUTBOARD CHORD STATION 727 FRAME

INSPECTION DETAIL LOCATIONS AND EDGE FOR POSSIBLE CRACK FWD FLANGE OUTBOARD CHORD STA 727 FRAME

PANEL FWD SKIN

CHORD OUTBOARD S-18A

BEAM SHEAR

S-18A

SKIN PANEL OF FWD LOWER EDGE SPLICE ANGLE OUTBOARD CHORD

STA 727 FRAME WEB BULKHEAD

STA 727

INBD AREA INSPECTION

**(SHEET 1 OF 2) FIGURE 8: EDDY CURRENT INSPECTION**  **- GROUPS 1 THROUGH 11, CONFIGURATION 1.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 137 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.
**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Frame Chord Forward Flange External Low Frequency Eddy Current (LFEC) (a) 737 NDT Part 6 Subject 53-30-00 Figure 5 (b) (c) For cracks

2 Inspect Frame Chord Forward Flange Forward Edge External High Frequency Eddy Current (HFEC) 737 NDT Part 6 Subject 51-00-00

Figure 4 or 23 (b) For cracks

(a) Use Reference Standard ANDT1053. (b) The Inspection is done from outside the airplane in the wheel well area. (c) Cracks can also be found between fasteners. 727 STA

FWD


### A 2D39254 SPLICE STRAP OUTBOARD CHORD STA 727 FRAME OUTBOARD CHORD STA 727 FRAME

OUTBOARD CHORD IN STA 727 FRAME TYPICAL CRACK

INBD SPLICE ANGLE OUTBOARD CHORD STA 727 FRAME AREA INSPECTION

**(SHEET 2 OF 2) FIGURE 9: SURFACE HFEC INSPECTION**  **- GROUPS 1 THROUGH 11, CONFIGURATION 4.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 138 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 9: SURFACE HFEC INSPECTION - GROUPS 1 THROUGH 11**  **, CONFIGURATION 4.**

727 STA

FWD INBD
(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) VIEW FROM INSIDE THE WHEEL WELL 1D39258 FORWARD FLANGE OUTBD CHORD STA 727 FRAME

SKIN PANEL FORWARD

CHORD OUTBD S-18A

BEAM SHEAR

S-18A

SKIN PANEL OF FORWARD LOWER EDGE UPRIGHT FLANGE OUTBD CHORD STA 727 FRAME

WEB BULKHEAD STA 727

CHORD FRAME OUTBD THE STA 727 LOCATION IN POSSIBLE CRACK AREA INSPECTION

**(SHEET 1 OF 2) FIGURE 9: SURFACE HFEC INSPECTION**  **- GROUPS 1 THROUGH 11, CONFIGURATION 4.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 139 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Frame Chord Forward Flange HFEC 737 NDT Part 6 Subject 51-00-00, Figure 4 or Figure 23 (a) (b) For cracks

(a) An External Inspection is done from outside the airplane in the wheel well area. (b) Cracks can also be found between fasteners.

**(SHEET 2 OF 2) FIGURE 10: OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE STA 727**  **OUTBOARD CHORD FORWARD FLANGE** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 140 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT FIGURE 10: OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE STA 727**  **OUTBOARD CHORD FORWARD FLANGE**

(WING-TO-BODY FAIRING NOT SHOWN) RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SEE AD39073

**(SHEET 1 OF 3) FIGURE 10: OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE STA 727**  **OUTBOARD CHORD FORWARD FLANGE** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 141 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

INBD FWD STA 727 STA 727

FLANGE FRAME FWD B SEE

3 

### A

B 3

FWD UP 2 1

2

1D40617 A FLAT STRAP) STRINGER 18A IS THE OUTER CHORD OF (ON MOST AIRPLANES STRINGER 18A

TYPICAL CRACK FWD SKIN AFT SKIN

STRUCTURE NOT SHOWN FOR CLARITY) (STRINGER 18A AND FAIRING SUPPORT

**(SHEET 2 OF 3) FIGURE 10: OPEN HOLE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE STA 727**  **OUTBOARD CHORD FORWARD FLANGE** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 142 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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.
**STEP TASK NAME IDENTIFICATION QTY MORE DATA CAUTION:**  MAKE SURE THE FASTENER HOLES AR E ROUND BEFORE PERFORMING THE HFEC OPEN HOLE INSPECTIONS. LOOSE FASTENERS MAY INDICATE HOLES THAT ARE NOT ROUND. MINIMIZE THE AMOUNT OF FASTENER HOLE REAMING USED TO CLEAN-UP HOLES FOR HFEC OPEN HOLES INSPECTIONS. LARGER FASTENER HOLES MAY IMPACT FUTURE INSPECTIONS AND THE ACCOMPLISHMENT OF PART 6 - STA 727 FRAME OUTBOARD CHORD PREVENTIVE MODIFICATION. 1 Remove Fastener - 4 2 Inspect Fastener Holes HFEC 4 (a) (b) For cracks as given in 737 NDT Part 6 Subject 51-00-00 Figure 16 3 Install Bolt - 4 (c) (d) (e) See Fastener Table 1 or 2. Collar - 4 (a) Use a 0.030 notch standard for inspection and repeat inspection program (b) Use a 0.020 notch standard for modification inspection requirements (c) Only necessary if no cracks are found and the PART 6 - STA 727 frame outboard chord preventive modification is not done before further flight. (d) Grip length to be determined on installation. (e) Use the replacement fasteners identified in Table 1 or Table 2. Select the correct fastener diameter that provides the smallest diameter required for a transition fit for all aluminum parts or a close ream fit for stack-ups that contain steel parts. Select the grip length that matches the removed fastener. Install wet using BMS5-95. Do not exceed 5/16 diameter
**Table 1: Stainless Steel Replacement Fasteners Bolt Collar**  Nominal BACB30MB*A* BACC30BH* 1/64 OverSize BACB30MC*A* BACC30BH* 1/32 OverSize BACB30MD*A* BACC30AC* 3/64 OverSize BACB30ME*A* BACC30U*
**Table 2: Alternate - Titanium Replacement Fasteners Bolt Collar**  Nominal BACB30NX*K* BACC30BH* 1/64 OverSize BACB30NX*K*X BACC30BH* 1/32 OverSize BACB30NX*K*Y BACC30AC* 3/64 OverSize - -

**(SHEET 3 OF 3) FIGURE 11: AUXILIARY CHORD INSPECTION**  **- GROUPS 1 THROUGH 3, CONFIGURATION 3.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 143 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 11: AUXILIARY CHORD INSPECTION - GROUPS 1 THROUGH 3, CONFIGURATION 3.** 

CHORD AUXILIARY

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) VIEW FROM INSIDE REAR CARGO BAY CRACK TYPICAL 727 STA 540 STA

STA 727

1 2 STA 727

BL 0 S-25 S-20 S-18 S-17

S-19

S-21

S-22

S-23

S-24

S-26 S-27



### A A SEED39431 FWD SPLICE SKIN LAP

SKIN AREA INSPECTION

CHORD AUXILIARY CHORD FRAME AFT SKIN

WEB BULKHEAD

**(SHEET 1 OF 2) FIGURE 11: AUXILIARY CHORD INSPECTION**  **- GROUPS 1 THROUGH 3, CONFIGURATION 3.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 144 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Auxiliary Chord Radius Detailed Inspection - For cracks
2 Inspect Auxiliary Chord Radius High Frequency Eddy Current (HFEC) 737 NDT Part 6 Subject 51-00-00 Figure 23 (a) For cracks

(a) 737 NDT Part 6 Subject 51-00-00 Figure 4 is an alternative procedure

**(SHEET 2 OF 2) FIGURE 12: AUXILIARY CHORD INSPECTION - GROUPS 1 THROUGH 3, CONFIGURATION 4.**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 145 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 12: AUXILIARY CHORD INSPECTION - GROUPS 1 THROUGH 3, CONFIGURATION 4.** 

CRACK TYPICAL (LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) VIEW FROM INSIDE REAR CARGO BAY 727 STA 540 STA

STA 727

1 2 STA 727

BL 0 S-25 S-20 S-18 S-17

S-19

S-21

S-22

S-23

S-24

S-26 S-27



### A A SEEJ23072 FWD SPLICE SKIN LAP

SKIN AREA INSPECTION

CHORD AUXILIARY

CHORD AUXILIARY CHORD FRAME AFT SKIN

WEB BULKHEAD

**(SHEET 1 OF 2) FIGURE 12: AUXILIARY CHORD INSPECTION**  **- GROUPS 1 THROUGH 3, CONFIGURATION 4.** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 146 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Auxiliary Chord Radius Detailed Inspection - For cracks
2 Inspect Auxiliary Chord Radius High Frequency Eddy Current (HFEC) 737 NDT Part 6 Subject 51-00-00 Figure 23 (a) For cracks

(a) 737 NDT Part 6 Subject 51-00-00 Figure 4 is an alternative procedure

**(SHEET 2 OF 2) FIGURE 13: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT**  **(HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUP 1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 147 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 13: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUP 1** 

(WING-TO-BODY FAIRING NOT SHOWN) RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SEE AD39074

**(SHEET 1 OF 3) FIGURE 13: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT**  **(HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUP 1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 148 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

INBD FWD AFT SKIN FWD SKIN

STRUCTURE SUPPORT FAIRING

AREA INSPECTION STA 727 STA 727

B SEE



### B 1 2 

### AD40618 STRINGER 18A

CRACK TYPICAL

18A STRINGER

**(SHEET 2 OF 3) FIGURE 13: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT**  **(HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUP 1** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 149 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Stringer Chord Detailed Inspection - For cracks
2 Inspect Stringer Chord HFEC 737 NDT Part 6 Subject 51-00-00 Figure 23 (a) For cracks

(a) 737 NDT Part 6 Subject 51-00-00 Figure 4 is an alternative procedure

**(SHEET 3 OF 3) FIGURE 14: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT**  **(HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUPS 2, 3, 4, 5, 6, 9 AND 10** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 150 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 14: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUPS 2, 3, 4, 5, 6, 9 AND 10** 

(WING-TO-BODY FAIRING NOT SHOWN) RIGHT SIDE OPPOSITE LEFT SIDE SHOWN SEE AD39075

**(SHEET 1 OF 3) FIGURE 14: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT**  **(HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUPS 2, 3, 4, 5, 6, 9 AND 10** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 151 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

INBD FWD AFT SKIN FWD SKIN

STRUCTURE SUPPORT FAIRING

AREA INSPECTION STA 727 STA 727

B SEE



### B 1 2 

### A

FWD UPD41124 STRINGER 18A

CRACK TYPICAL STRINGER 18A

**(SHEET 2 OF 3) FIGURE 14: EXTERNAL DETAILED INSPECTION AND SURFACE HIGH FREQUENCY EDDY CURRENT**  **(HFEC) INSPECTION OF THE S-18A OUTBOARD CHORD - GROUPS 2, 3, 4, 5, 6, 9 AND 10** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 152 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Stringer Chord Detailed Inspection - For cracks
2 Inspect Stringer Chord HFEC 737 NDT Part 6 Subject 51-00-00 Figure 23 (a) For cracks

(a) 737 NDT Part 6 Subject 51-00-00 Figure 4 is an alternative procedure

**(SHEET 3 OF 3) FIGURE 15: PREPARATION FOR THE STA 7**  **27 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 153 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 15: PREPARATION FOR THE STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR** 

SUPPORT FITTING FLAP TRACK

S-26

END OF CHORD S-25

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) 

### STA 727 - BULKHEAD S-22

S-24 S-23 S-20 S-18A S-17

0 BL BL 0 STA 727

S-27 BEAM SHEAR S-18A SEE AD39440 FWD INBD

**(SHEET 1 OF 7) FIGURE 15: PREPARATION FOR THE STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 154 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

SHOWN RIGHT SIDE SIMILAR) AFT SKIN NOT SHOWN (LEFT SIDE VIEW LOOKING AFT STA 727 BULKHEAD WEB OUTBOARD CHORD STA 727 FRAME

CHORD OUTBOARD S-18A

BEAM SHEAR S-18A FORWARD SKIN

S-18A

A A B

B MEASUREMENT CLEARANCE

INBD 2

5

6
S-20 WL 190



### A 2D39444

**(SHEET 2 OF 7) FIGURE 15: PREPARATION FOR THE STA 7**  **27 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 155 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

WEB BULKHEAD CHORD OUTBOARD FRAME CHORD

AUXILIARY AFT SKIN

STIFFENER HORIZONTAL

AIRPLANES ON SOME ANGLE ONLY OF JOGGLE FWD END

FWD SKIN FILLER TAPERED

AREA TRIMMED BEAM WEB SHEAR MEASUREMENT CLEARANCE

727 STA

C C

INBD

FWD 8 9

4 10

7 9 3D39455



### A-A

**(SHEET 3 OF 7) FIGURE 15: PREPARATION FOR THE STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 156 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

S-18A 1 727 STA

1

FWD UP 7 9 (6 LOCATIONS)

AND STOP DRILL

TYPICAL CRACK

CHORD FRAME OUTBOARDD40213



### B-B CHORD AUXILIARY

BULKHEAD WEB SHEAR BEAM

STIFFENER HORIZONTAL

CONFIGURATION SHEAR BEAM SHOWN IN TRIMMED HORIZONTAL STIFFENER AND MEASUREMENT CLEARANCE

**(SHEET 4 OF 7) FIGURE 15: PREPARATION FOR THE STA 7**  **27 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 157 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

S-18A 727 STA

FWD UP

CHORD FRAME OUTBOARD 4 3J66908 

### C-C CHORD AUXILIARY

BULKHEAD WEB SHEAR BEAM

STIFFENER HORIZONTAL

SHEAR BEAM SHOWN BEFORE TRIM HORIZONTAL STIFFENER AND MEASUREMENT CLEARANCE

MEASUREMENT CLEARANCE

**(SHEET 5 OF 7) FIGURE 15: PREPARATION FOR THE STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 158 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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.
**STEP TASK NAME IDENTIFICATION QTY MORE DATA**
1 Inspect Fastener Hole Distance - - (a) (e)

2 Inspect Fastener Hole Distance - - (a) (f)

3 Inspect Fastener Hole Distance - - (a) (g)
4 Inspect Edge Margin - - (a) (h)
5 Remove/ Keep Tee 65-48692-( ) 1 Remove and keep shims if installed.

6 Remove/ Keep Bracket 69-39436-( ) 1 Left Side. Remove and keep shims if installed. 69-39437-( ) 1 Right Side. Remove and keep shims if installed.

7 Cut Shear Beam Web - - (b) (c) Trim the aft part of the outboard vertical side to allow for the installation of the frame chord repair angle. Trim the forward end of the joggle. Remove attaching fasteners.

8 Cut Horizontal Stiffener - - (b) (c) Trim the outboard part of the vertical leg to allow for the installation of the frame chord repair angle. Remove attaching fasteners.

9 Apply Chemical Conversion Coating Type 2, Class A - (d) As given in SOPM 20-43-03.
Primer BMS 10-11, Type 1 - (d) 2 coats as given in SOPM 20-41-02. 10 Remove Tapered Filler 65-46877-( ) 1 (a) If the Time-Limited repair cannot be accomplished, replace the chord as shown in PART 3 - STA 727 Frame Outboard Chord Repair. (b) Maintain a 1.7D minimum edge margin and a 0.375 minimum radius. (c) Protect the remaining structure during trimming. (d) To all trimmed edges. (e) Make sure the replacement fastener collars can clear the radius of the nested frame chord repair angle. Fastener centerline to bulkhead web distance must be more than 0.58 inches to provide collar clearance.

**(SHEET 6 OF 7) FIGURE 15: PREPARATION FOR THE STA 7**  **27 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 159 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

(f) Make sure replacement fastener collars can clear the nested shear beam repair angle. Fastener centerline to shear beam web distance must be more than 0.36 inches to provide collar clearance. (g) Make sure replacement fastener collars can clear the repair strap. Fastener centerline to horizontal stiffener distance must be more than 0.39 inches to provide collar clearance. (h) The horizontal stiffener repair strap may reduce the available edge margin for the shear beam repair angle. Fastener centerline to the horizontal stiffener distance must be a minimum 0.43 inches to provide sufficient edge margin for installation of 1/4 inch diameter fastener into the shear beam repair angle. This distance must be a minimum 0.45 inches for a 1/4+1/64 oversize fastener. This distance must be a minimum 0.46 inches for a 1/4 + 1/32 oversize fastener.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 7 OF 7) FIGURE 16: TIME-LIMITED REPAIR - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPEC**  **TION FOR CRACK TIP LOCATION** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 160 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT FIGURE 16: TIME-LIMITED REPAIR - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC)**  **INSPECTION FOR CRACK TIP LOCATION**

SUPPORT FITTING FLAP TRACK

S-26

END OF CHORD S-25

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) 

### STA 727 - BULKHEAD S-22

S-24 S-23 S-20 S-18A S-17

0 BL BL 0 STA 727

S-27 BEAM SHEAR S-18A SEE AD39443 FWD INBD

**(SHEET 1 OF 3) FIGURE 16: TIME-LIMITED REPAIR - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPEC**  **TION FOR CRACK TIP LOCATION** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 161 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

RIGHT SIDE SIMILAR)

(LEFT SIDE SHOWN AFT SKIN NOT SHOWN

VIEW LOOKING AFT STA 727 BULKHEAD WEB OUTBOARD CHORD STA 727 FRAME

CHORD OUTBOARD S-18A

BEAM SHEAR S-18A SKIN FORWARD

S-18A 

### A

A

INBD S-20 WL 190



### AD40214

**(SHEET 2 OF 3) FIGURE 16: TIME-LIMITED REPAIR - SURFACE HIGH FREQUENCY EDDY CURRENT (HFEC) INSPEC**  **TION FOR CRACK TIP LOCATION** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 162 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure. 

### REPAIR INSPECTION

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Frame Chord Forward Flange HFEC 737 NDT Part 6 Subject 51-00-00 Figure 23 (a) Identify the location of the crack tip. (a) 737 NDT Part 6 Subject 51-00-00 Figure 4 is an alternative procedure. S-18A 727 STA

FWD UP TYPICAL CRACK

CHORD FRAME OUTBOARD 1 LENGTH CRACK MAXIMUMD40215



### A-A CHORD AUXILIARY

BULKHEAD WEB SHEAR BEAM

**(SHEET 3 OF 3) FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 163 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS**

A

A 10 1 10 1D40216


### A-A

**(SHEET 1 OF 5) FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 164 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

FLANGE, IF REQUIRED AREA OF EXTENDED 4.25

1.25 1.25 6.0

8.2

1.4 1.4 1.2

8.2 2 10 3

4 5

6

6 10

10 10

10

10 6 10D39079

**(SHEET 2 OF 5) FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 165 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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.

**STEP TASK NAME MATERIAL QTY MORE DATA** 1 Make Frame Repair Angle AND10134-2008 or equivalent x 20.8 inches. 7075-T0 1 (a) (k)
Cut Frame Repair Angle - 1 (p)
Bend Frame Repair Angle - 1 To match frame.

Heat Treat Frame Repair Angle - 1 Heat Treat to T6 condition.
2 Make Shim A 7075-T6 clad sheet 1 (a) (b) (j) 0.032 inch thick. 3 Make Repair Strap 7075-T6 clad sheet 1 (a) (j) 0.18 inch thick. 4 Make Filler A 7075-T6 clad sheet 1 (a) (c) 0.14 inch thick. 5 Make Filler B 7075-T6 clad sheet 1 (a) (d) 0.202 inch thick, tolerance +/- 0.01inches. 6 Make Shear Beam Repair Angle 4.25 X 8.2 inches 7075-T0 clad sheet 1 (a) (f) (g) (n) (q) 0.15 inch thick.
Bend Vertical Flange - 1 (e) (h) Heat Treat Shear Beam Repair Angle - 1 Heat Treat to T6 condition.
7 Make Shim B 7075-T6 clad sheet 1 (a) (l) 0.18 inch thick 2.1 11.4

8.7

1.2 7

8 10

10 6.9

1.6

0.01 0.01 0.09 9 10 1.9J77517

**(SHEET 3 OF 5) FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 166 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

8 Make Shim C 7075-T6 clad sheet 1 (a) (m) 0.18 inch thick 9 Make Filler (Tapered) 7075-T6 clad sheet 1 (a) (o) (r) 0.09 inch thick. 10 Apply Chemical Conversion Coating Type 2, Class A - (i) As given in SOPM 20-43-03.

Primer BMS 10-11, Type 1 - (i) 2 coats as given in SOPM 20-41-02. (a) Break sharp edges and remove burrs. (b) Airplanes where the Bulkhead Attachment Angle at WL 190 is 0.125 inch thick, make shim from 7075-T6 clad sheet, 0.063 inch thick. (c) Airplanes where the S-18A Shear Beam flange is 0.125 inch thick, make the Filler from 7075-T6 clad sheet, 0.125 inch thick. (d) Airplanes where the S-18A Shear Beam flange is 0.125 inch thick, make the shim from 7075-T6 clad sheet, 0.217 inch thick, tolerance +/- 0.01inches. (e) Refer to 737-100/200 SRM 51-20-1 or 737-300/400/500 SRM 51-30-01. Minimum bend radius of 0.44. (f) If required, extend the vertical flange aft, as illustrated on sheet 2 of this figure, to obtain a minimum fastener hole edge margin of 1.7D (g) If required, chamfer the vertical flange aft edge to 0.10 x 45 degrees to nest in the radius of the Step 1 frame repair angle. (h) Bend the vertical flange to fit with the Step 5 Filler B and Step 1 Frame Repair Angle on installation. (i) All fabricated parts. (j) These detailed parts have been sized to attach with five fasteners. Interference may occur with the most inboard fastener position. If required, these parts can be trimmed and installed using four fasteners. (k) If required, the inboard edge of the repair angle can be trimmed to prevent interference with fasteners common to the bulkhead inboard of the STA 727 frame chord. Maintain a minimum fastener hole edge margin of 1.7D. (l) Dimensions shown are typical. Use the Tee removed in Step 5 of Figure 15 as a template for the correct size and shape. (m) Dimensions shown are typical. Use the Bracket removed in Step 6 of Figure 15 as a template for the correct size and shape. (n) To provide the operator with additional edge margin in the horizontal flange and to maintain fastener spacing, the repair angle is fabricated 0.25 inch oversize. Trim a maximum of 0.25 inch locally as required. Maintain a minimum fastener hole edge margin of 1.7D. (o) Size the filler and the taper to fit in the gap between the shear beam and the shear beam repair angle. **STEP TASK NAME MATERIAL QTY MORE DATA**

**(SHEET 4 OF 5) FIGURE 17: MAKE THE TIME-LIMITED REPAIR PARTS**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 167 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

(p) Use the airplane to correctly size and trim the frame repair angle. Trim the upper end of the frame repair angle to install just below S-18. Provide a minimum 1.5D edge margin in the frame repair angle for the first row of fasteners below S-18 common to the skin. Trim the lower end of the frame repair angle providing a minimum 1.5D edge margin for the second fastener row below S-20 common to the frame inboard flange. Trim away the forward leg of the frame repair angle to match the STA 727 frame outboard chord trim. (q) For airplanes with angles installed in production in the center of the shear beam web, trim the inboard edge of the horizontal flange of the shear beam repair to accommodate the production angle. Maintain a 1.5D minimum edge margin. (r) For airplanes with angles installed in production in the center of the shear beam web, trim the inboard edge of the filler to accommodate the production angle. Maintain a 1.5D minimum edge margin. For airplanes without the angle installed in production, the filler shall be 1.9 inches wide. **STEP TASK NAME MATERIAL QTY MORE DATA**

**(SHEET 5 OF 5) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 168 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**

SUPPORT FITTING FLAP TRACK

S-26

END OF CHORD S-25

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) 

### STA 727 - BULKHEAD S-22

S-24 S-23 S-20 S-18A S-17

0 BL BL 0 STA 727

S-27 BEAM SHEAR S-18A SEE AD39441 FWD INBD

**(SHEET 1 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 169 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

REFERENCE FASTENER

FASTENER REMOVED EXISTING A A

B B

INBD

RIGHT SIDE SIMILAR)

(LEFT SIDE SHOWN AFT SKIN NOT SHOWN

VIEW LOOKING AFT 

### A CHORD OUTBOARD S-18A FRAME OUTBOARD CHORD

SKIN FORWARD

BULKHEAD WEB REPAIR ANGLE FRAME CHORD

REPAIR ANGLE SHEAR BEAM

REPAIR STRAP

TEE

BRACKETD40217 5 4

WL 190 S-18A

S-20

3 2 1

6 4 3 2 1 7 10 4 3 2 1

15 14 13 12 16 17

15 14 13 12 16 17 18

19 S-18

**(SHEET 2 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 170 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

FASTENER REMOVED EXISTING

NEW FASTENER AUXILIARY CHORD

AFT SKIN

BULKHEAD WEB

SOME AIRPLANES

ANGLE ONLY ON

SHEAR BEAM WEB FWD SKIN FRAME OUTBOARD CHORD

OUTBOARD FLANGE SHEAR BEAM REPAIR ANGLE FRAME CHORD

FILLER A

FILLER B

FWD INBD STA 727 1 2 3 4

1 2 3 4 5

1 2 3 4 8

1 2 3 4 9 1 2 3 4 10 1 2 3 4 7 6 SHIM A

REPAIR STRAP

REPAIR ANGLE SHEAR BEAMD40219



### A-A

**(SHEET 3 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 171 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

REFERENCE FASTENER REMOVED EXISTING FASTENER NEW FASTENER FWD FILLER A REPAIR ANGLE SHEAR BEAM

FILLER B

S-20 STA 727

S-18

S-18A
S-19 1 CHORD OUTBOARD

FWD SKIN

2 3 4 5

1 2 3 4 8 1 2 3 4 10 1 2 3 4 9

1 2 3 4 11 REPAIR ANGLE

FRAME CHORDD40226

VIEW LOOKING OUTBOARD 

### B-B CHORD AUXILIARY WEB BULKHEAD

SHEAR BEAM

FILLER (TAPERED)

**(SHEET 4 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 172 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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 a one side of the airplane.
**STEP TASK NAME IDENTIFICATION QTY MORE DATA CAUTION:**  WHEN PERFORMING THE REPLACEMENT OF THE STA 727 FRAME OUTBOARD CHORD TIME-LIMITED REPAIR IT IS DESIRABLE TO MINIMIZE THE GROWTH OF THE FASTENER HOLE DIAMETERS WHEN INSTALLING FASTENERS. LARGER FASTENER HOLES MAY IMPACT FUTURE INSPECTIONS AND THE ACCOMPLISHMENT OF PART 6 - STA 727 FRAME OUTBOARD CHORD PREVENTIVE MODIFICATION

1 Align Frame Chord Repair Angle - 1

Shim Shim A 1 Repair Strap - 1 Filler Filler A 1 Filler Filler B 1 Shear Beam Repair Angle - 1
Filler Filler (Tapered) 1

2 Drill Frame Chord Repair Angle - 1 (a) (b) (j)

Shim Shim A 1 Repair Strap - 1 Filler Filler A 1 Filler Filler B 1 Shear Beam Repair Angle - 1
Filler Filler (Tapered) 1

3 Remove Frame Chord Repair Angle - 1

Shim Shim A 1 Repair Strap - 1 Filler Filler A 1 Filler Filler B 1 Shear Beam Repair Angle - 1
Filler Filler (Tapered) 1

**(SHEET 5 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 173 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

4 Deburr Frame Chord Repair Angle - 1

Shim Shim A 1 Repair Strap - 1 Filler Filler A 1 Filler Filler B 1 Shear Beam Repair Angle - 1
Filler Filler (Tapered) 1
5 Install Frame Chord Repair Angle - 1 (c) (d) (e) (f) (g) (h) (k)
6 Install Shim Shim A 1 (c) (d) (e) (f) (h) (k) 7 Install Repair Strap - 1 (c) (d) (e) (f) (h) (k) 8 Install Filler Filler A 1 (c) (d) (e) (f) (h) (k) 9 Install Filler Filler B 1 (c) (d) (e) (f) (h) (k)
10 Install Shear Beam Repair Angle - 1 (c) (d) (e) (f) (g) (h) (k)
11 Install Filler Filler (Tapered) 1 (c) (d) (e) (f) (h) (k)

12 Cut Shim Shim B 1 (i) Shim Shim C 1 (i)

13 Apply Chemical Conversion Coating Type 2, Class A - To the bare edges as given in SOPM 20-43-03.
Primer BMS 10-11, Type 1 - 2 coats as given in SOPM 20-41-02.

14 Align (New) Shim B - 1 Shim C - 1 Align (Kept) Tee 65-48692-( ) 1 Bracket 69-39436-( ) 1 Left Side. 69-39437-( ) 1 Right Side.

15 Drill Shim B - 1 Shim C - 1 Tee 65-48692-( ) 1 Bracket 69-39436-( ) 1 Left Side. 69-39437-( ) 1 Right Side.

16 Remove Shim B - 1 Shim C - 1 Tee 65-48692-( ) 1 Bracket 69-39436-( ) 1 Left Side. 69-39437-( ) 1 Right Side. **STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 6 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 174 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

17 Deburr Shim B - 1 Shim C - 1 Tee 65-48692-( ) 1 Bracket 69-39436-( ) 1 Left Side. 69-39437-( ) 1 Right Side.

18 Install Shim Shim B 1 (c) (d) (e) (f) (h) (k) Install (Kept) Tee 65-48692-( ) 1 (l) (m) Removed in Step 5 of Figure 15.

19 Install Shim Shim C 1 (c) (d) (e) (f) (h) (k) Install (Kept) Bracket 69-39436-( ) 1 (l) (m) Left Side. Removed in Step 6 of Figure 15. 69-39437-( ) 1 (l) (m) Right Side. Removed in Step 6 of Figure 15. (a) Drill fastener holes matching the existing fastener hole nominal size, within a close ream tolerance. If necessary holes may be oversized by up to 3/64th, but should not exceed 0.2973 (1/4 + 3/64 oversize). (b) Maintain a 1.7D minimum edge margin. (c) Shim all gaps greater than 0.01 before fastener installation. (d) Install wet with sealant (Ref. BMS 5-95). (e) Replace protruding head hex drive or lock bolt fasteners in transition fit holes with the same size as removed. If necessary use up to 1/32 oversize. See Fastener Installation Table for replacement fastener and collar types. (f) Replace 100 degree countersunk hex drive or lock bolt fasteners in transition fit holes with the same size as removed. If necessary use up to 1/32 oversize. See Fastener Installation Table for replacement fastener and collar types. (g) For new fastener locations, install BACB30MB8A( ) and BACC30BH8 fasteners and collars. (h) Install hex drive fasteners and bolts wet with sealant (Ref. BMS 5-95). (i) Cut the outboard end of the shim so it will be flush with the frame chord repair angle. (j) Adjust fastener pattern common to the Shear Beam horizontal web to adapt to existing fastener pattern. Maintain 1.7D minimum edge margin. For new fastener locations, maintain 3D to 6D fastener spacing, staggered fastener pattern is acceptable. Use the same quantity of fasteners as indicated. (k) Replace rivets with the same size and type. (l) Common to the STA 727 frame outboard chord, replace hexdrive, lock bolts and bolts with the same type and smallest size to maintain a transition fit hole. Do not exceed 5/16 inch diameter for these fasteners. (m) Common to the STA 727 frame outboard chord, replace rivets with the same type and size rivets. Do not exceed 6/32 inch diameter rivet for replacement of a production 5/32 inch diameter rivet. Do not exceed 1/4 inch diameter rivet for replacement of a production 6/32 inch diameter rivet.

**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 7 OF 8) FIGURE 18: INSTALL THE TIME-LIMITED REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 175 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

**Fastener Installation Table Removed Existing**  **Fastener New Fastener and Collar**  **Existing Size 1/64 Oversize 1/32 Oversize** Protruding Head BACB30MB( )A( ) + BACC30BH( ) BACB30MC( )A( ) + BACC30BH( ) BACB30MD( )A( ) + BACC30AC( ) Countersunk BACB30FN( )A( ) + BACC30M( ) BACB30FQ( )A( ) + BACC30M( ) BACB30KF( )A( ) + BACC30R( ) None (New Fastener) BACB30MB8A( ) + BACC30BH8 - -

**(SHEET 8 OF 8) FIGURE 19: TIME-LIMITED REPAIR - REMOVAL**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 176 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 19: TIME-LIMITED REPAIR - REMOVAL**

SUPPORT FITTING FLAP TRACK

S-26

END OF CHORD S-25

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) 

### STA 727 - BULKHEAD S-22

S-24 S-23 S-20 S-18A S-17

0 BL BL 0 STA 727

S-27 BEAM SHEAR S-18A SEE AD40866 FWD INBD

**(SHEET 1 OF 5) FIGURE 19: TIME-LIMITED REPAIR - REMOVAL**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 177 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

A A

B B

INBD



### A CHORD OUTBOARD S-18A FRAME OUTBOARD CHORD

SKIN FORWARD

BULKHEAD WEB

RIGHT SIDE SIMILAR) (LEFT SIDE SHOWN AFT SKIN NOT SHOWN

VIEW LOOKING AFTD40867 4

2 1 8

WL 190 S-18A

S-20 3 5

**(SHEET 2 OF 5) FIGURE 19: TIME-LIMITED REPAIR - REMOVAL**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 178 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

AFT SKIN

BULKHEAD WEB

SOME AIRPLANES

ANGLE ONLY ON

SHEAR BEAM WEB FWD SKIN

OUTBOARD FLANGE SHEAR BEAM AUXILIARY CHORD

CHORD OUTBOARD FRAME

FWD INBD 3 4
STA 727

5 6 8

7 1 2 3 4 7 REPAIR STRAPD40868



### A-A

**(SHEET 3 OF 5) FIGURE 19: TIME-LIMITED REPAIR - REMOVAL**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 179 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

FWD 6
5 7

S-20 STA 727

S-18

S-18A
S-19 8 CHORD OUTBOARD

FWD SKIN

9D40869

VIEW LOOKING OUTBOARD 

### B-B CHORD AUXILIARY WEB BULKHEAD

SHEAR BEAM

**(SHEET 4 OF 5) FIGURE 19: TIME-LIMITED REPAIR - REMOVAL**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 180 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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.
**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

1 Remove/Keep Tee 65-48692-( ) 1 Remove Shim Shim B 1

2 Remove/Keep Bracket 69-39436-( ) 1 Left Side. 69-39437-( ) 1 Right Side. Remove Shim Shim C 1 3 Remove/Keep Repair Strap - 1 4 Remove Shim Shim A 1
5 Remove Shear Beam Repair Angle - 1

6 Remove Filler Filler B 1 7 Remove Filler Filler A 1
8 Remove Frame Chord Repair Angle - 1
9 Remove Filler Filler (Tapered) 1

**(SHEET 5 OF 5) FIGURE 20: MAKE THE REPLACEMENT PARTS TO REPLACE THE TIME-LIMITED REPAIR WITH A**  **NEW FRAME CHORD** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 181 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 20: MAKE THE REPLACEMENT PARTS TO REPLACE THE TIME-LIMITED REPAIR WITH A NEW FRAME CHORD** 

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.
**Note:** Make the repair parts as shown in the table that follows. The dimensions provided are target values, use existing parts as guides to make sure correct fit and a minimum fastener hole edge margin of 1.7D is obtained.
**STEP TASK NAME MATERIAL QTY MORE DATA** 1 Make Filler A 7075-T6 clad sheet. 1 (a) (b) Thickness to match existing WL 190 Horizontal Stiffener. Target thickness is 0.156 or 0.125 inches. 2 Make Filler B 7075-T6 bare. 1 (a) (c) 3 Apply Chemical Conversion Coating Type 2, Class A - (d) As given in SOPM 20-43-03.
Primer BMS 10-11, Type 1 - (d) 2 coats as given in SOPM 20-41-02. (a) Break sharp edges and remove burrs. 1 3 1.5

1.75

0.15

1.0

0.85 0.02

2 3D40872

**(SHEET 1 OF 2) FIGURE 20: MAKE THE REPLACEMENT PARTS TO REPLACE THE TIME-LIMITED REPAIR WITH A**  **NEW FRAME CHORD** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 182 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

(b) Trim the outboard end to match the contour of the frame. (c) Measure the length of the shear beam joggle gap. Size the length of the constant thickness section of the filler to fill the joggle gap. (d) All fabricated parts. **STEP TASK NAME MATERIAL QTY MORE DATA**

**(SHEET 2 OF 2) FIGURE 21: STRINGER S-18A OUTBOARD CHORD AFT FASTENERS - INSPECTION - GROUP 1, 2, 3,**  **4, 5, 6 AND 9** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 183 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT FIGURE 21: STRINGER S-18A OUTBOARD CHORD AFT FASTENERS - INSPECTION - GROUP 1, 2, 3, 4,**  **5, 6 AND 9**

LEFT SIDE SHOWN RIGHT SIDE OPPOSITE (WING-TO-BODY FAIRING NOT SHOWN) S-19 S-18A

S-20 S-17 STA 716 STA 709

727A (737-200/300/400/500) STA 747 (737-100) STA 727

S-18

SEE AD41498

**(SHEET 1 OF 2) FIGURE 21: STRINGER S-18A OUTBOARD CHORD AFT FASTENERS - INSPECTION - GROUP 1, 2, 3,**  **4, 5, 6 AND 9** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 184 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Fasteners General Visual Inspection - (a)
(a) Record the quantity of fasteners in the S-18A outboard chord aft of the STA 727 frame. CHORD OUTBOARD S-18A SKIN ASSEMBLY

PATTERN SHOWN TYPICAL FASTENER



### A FWD UP 1D40231

NOT SHOWN FOR CLARITY FAIRING SUPPORT STRUCTURE (737-100) 747 STA

(737-200/300/400/500) 727A STA

S-19 727 STA

**(SHEET 2 OF 2) FIGURE 22: STA 727 OUTBOARD CHORD FORWARD FLANGE AT STRINGER 18A - EVALUATION**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 185 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 22: STA 727 OUTBOARD CHORD FORW ARD FLANGE AT STRINGER 18A - EVALUATION** 



### A A STA 727

INBD

RIGHT SIDE SIMILAR LEFT SIDE SHOWN AFT SKIN NOT SHOWN S-20 S-18A WL 190

UP BULKHEAD SKIND39442

**(SHEET 1 OF 2) FIGURE 22: STA 727 OUTBOARD CHORD FORWARD FLANGE AT STRINGER 18A - EVALUATION**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 186 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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.
**STEP TASK NAME IDENTIFICATION QTY MORE DATA** 1 Measure Edge Margin - 2 (a) 2 Inspect Fastener Holes - 4 (b) (a) Measure the distance from the center of the fastener hole to the forward edge of the STA 727 frame outboard chord. (b) Make sure the fastener holes are round. S-18A 1

1 727 STA

2

FWD UPD39837



### A-A CHORD AUXILIARY BULKHEAD WEB

FORWARD EDGE FRAME CHORD

EDGE MARGIN

**(SHEET 2 OF 2) FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 187 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**

SUPPORT FITTING FLAP TRACK

S-26

END OF CHORD S-25

(LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) 

### STA 727 - BULKHEAD S-22

S-24 S-23 S-20 S-18A S-17

0 BL BL 0 STA 727

S-27 BEAM SHEAR S-18A SEE AD40884 FWD INBD

**(SHEET 1 OF 6) FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 188 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

AND FILLER A REPAIR STRAP

REFERENCE FASTENER REMOVED EXISTING FASTENER A A

B B

INBD

RIGHT SIDE SIMILAR)

(LEFT SIDE SHOWN AFT SKIN NOT SHOWN

VIEW LOOKING AFT 

### A CHORD OUTBOARD S-18A FRAME OUTBOARD CHORD

SKIN FORWARD

BULKHEAD WEB 1 2 3 4 5 6 7D40878 10 WL 190 S-18A

S-20 9

**(SHEET 2 OF 6) FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 189 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

AFT SKIN

BULKHEAD WEB

SOME AIRPLANES

ANGLE ONLY ON FWD SKIN

OUTBOARD FLANGE SHEAR BEAM FRAME OUTBOARD CHORD AUXILIARY CHORD

AIRPLANES ON SOME DOUBLER ONLY REPAIR STRAP

FWD INBD STA 727 1 2 3 4 5 6 7

1 2 3 4 5 6 8

1 2 3 4 8 FILLER A

FILLER B

SHEAR BEAMD40893



### A-A

**(SHEET 3 OF 6) FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 190 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

FASTENER REMOVED EXISTING

FWD S-20 STA 727

S-18

S-18A
S-19 CHORD OUTBOARD

FWD SKIN

1 2 3 4 5 6 8

1 2 3 4 8 SHEAR BEAM FILLER BD40911

VIEW LOOKING OUTBOARD 

### B-B CHORD AUXILIARY WEB BULKHEAD

**(SHEET 4 OF 6) FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 191 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **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.
**STEP TASK NAME IDENTIFICATION QTY MORE DATA**

1 Align Filler A (Refer to Step 1 of Figure 20.) 1 Repair Strap (Refer to Step 3 of Figure 19.) 1 Filler B (Refer to Step 2 of Figure 20.) 1 Shear Beam Web - 1 (a) As shown in drawing 65-46877.

2 Drill Filler A (Refer to Step 1 of Figure 20.) 1 (b) (c) Repair Strap (Refer to Step 3 of Figure 19.) 1 (b) (c) Filler B (Refer to Step 2 of Figure 20.) 1 Shear Beam Web - 1 (a) As shown in drawing 65-46877.

3 Remove/ Keep Filler A (Refer to Step 1 of Figure 20.) 1 Repair Strap (Refer to Step 3 of Figure 19.) 1 Filler B (Refer to Step 2 of Figure 20.) 1 Shear Beam Web - 1 (a) As shown in drawing 65-46877.

4 Deburr Filler A (Refer to Step 1 of Figure 20.) 1 Repair Strap (Refer to Step 3 of Figure 19.) 1 Filler B (Refer to Step 2 of Figure 20.) 1 Shear Beam Web - 1 (a) As shown in drawing 65-46877.

5 Apply Chemical Conversion Coating Type 2, Class A - To the bare edges as given in SOPM 20-43-03.
6 Apply Primer BMS 10-11 Type 1 - 2 coats as given in SOPM 20-41-02.

7 Install (Kept) Filler A (Refer to Step 1 of Figure 20.) 1 (d) (e) (f) (g) (h) (i) (j)

Install (Kept) Repair Strap (Refer to Step 3 of Figure 19.) 1 (d) (e) (f) (g) (h) (i) (j)

8 Install (Kept) Filler B (Refer to Step 2 of Figure 20.) 1 (d) (e) (f) (g) (h) (i) (j)

Install (New) Shear Beam Web - 1 (a) As shown in drawing 65-46877.

9 Install (Kept) Tee 65-48692-( ) 1 (k) (l) Install the Tee removed in Step 1 of Figure 19.

**(SHEET 5 OF 6) FIGURE 23: INSTALL THE SHEAR BEAM REPAIR**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 192 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

10 Install (Kept) Bracket 69-39436-( ) 1 (k) (l) Left Side. Install the Bracket removed in Step 2 of Figure 19. 69-39437-( ) 1 (k) (l) Right Side. Install the Bracket removed in Step 2 of Figure 19. (a) Refer to Paragraph 3.B. Accomplishment Instructions Part 9 Paragraph e. for part number of Shear Beam Web applicable to Airplane Group. (b) Drill fastener holes matching the existing fastener hole nominal size, within a transition fit tolerance. If necessary holes may be oversized by up to 3/64th, but should not exceed 0.2973 (1/4 + 3/64 oversize). (c) Maintain a 1.7D minimum edge margin. (d) Shim all gaps greater than 0.01 before fastener installation. (e) Install wet with sealant (Ref. BMS 5-95). (f) Replace protruding head hex drive or lockbolt fasteners in transition fit holes with the same size as removed. If necessary use up to 1/32 oversize while maintaining a 1.7D minimum edge margin. Do not exceed 5/16 inch diameter. See Fastener Installation Table. (g) Replace 100 degree countersunk hex drive or lockbolt fasteners in transition fit holes with the same size as removed. If necessary use up to 1/32 oversize while maintaining a 1.7D minimum edge margin. Do not exceed 5/16 inch diameter. See Fastener Installation Table. (h) Install hex drive fasteners and bolts wet with sealant (Ref. BMS 5-95). (i) If PART 3 or PART 6 requires different fasteners, use the fasteners given in PART 3 or PART 6. (j) Replace rivets with the same size and type. (k) Replace hexdrive, lock bolts and bolts with the same type and smallest size to maintain a transition fit hole. Do not exceed 5/16 inch diameter for these fasteners. (l) Replace rivets with the same type and size rivets. Do not exceed 6/32 inch diameter rivet for replacement of a production 5/32 inch diameter rivet. Do not exceed 1/4 inch diameter rivet for replacement of a production 6/32 inch diameter rivet.

**Fastener Installation Table Removed Existing**  **Fastener New Fastener and Collar**  **Existing Size 1/64 Oversize 1/32 Oversize** Protruding Head BACB30MB( )A( ) + BACC30BH( ) BACB30MC( )A( ) + BACC30BH( ) BACB30MD( )A( ) + BACC30AC( ) Countersunk BACB30FN( )A( ) + BACC30M( ) BACB30FQ( )A( ) + BACC30M( ) BACB30KF( )A( ) + BACC30R( ) **STEP TASK NAME IDENTIFICATION QTY MORE DATA**

**(SHEET 6 OF 6) FIGURE 24: AUXILIARY CHORD INSPECTION**  **- GROUPS 1 THROUGH 3, CONFIGURATION 1; GROUPS 4 THROUGH 11, CONFIGURATION 1 AND 4**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 193 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**FIGURE 24: AUXILIARY CHORD INSPECTION - GR OUPS 1 THROUGH 3, CO**  **NFIGURATION 1; GROUPS 4 THROUGH 11, CONF**  **IGURATION 1 AND 4**

CRACK TYPICAL (LEFT SIDE SHOWN, RIGHT SIDE SIMILAR) VIEW FROM INSIDE REAR CARGO BAY 727 STA 540 STA

STA 727

1 2 STA 727

BL 0 S-25 S-20 S-18 S-17

S-19

S-21

S-22

S-23

S-24

S-26 S-27



### A A SEEU34781 FWD SPLICE SKIN LAP

SKIN AREA INSPECTION

CHORD AUXILIARY

CHORD AUXILIARY CHORD FRAME AFT SKIN

WEB BULKHEAD

**(SHEET 1 OF 2) FIGURE 24: AUXILIARY CHORD INSPECTION**  **- GROUPS 1 THROUGH 3, CONFIGURATION 1; GROUPS 4 THROUGH 11, CONFIGURATION 1 AND 4**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 194 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** The step numbers shown below agree with the numbers shown in the circle symbols in the figure.

**STEP TASK NAME PROCEDURE REFERENCES MORE DATA** 1 Inspect Auxiliary Chord Radius Detailed Inspection - For cracks
2 Inspect Auxiliary Chord Radius High Frequency Eddy Current (HFEC) 737 NDT Part 6 Subject 51-00-00 Figure 23 (a) For cracks

(a) 737 NDT Part 6 Subject 51-00-00 Figure 4 is an alternative procedure

**(SHEET 2 OF 2) APPENDIX A: ADDENDUM**  June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 195 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**
**APPENDIX A: ADDENDUM**
FLIGHT SAFETY SECTION INSPECTION TO ENSURE STRUCTURAL INTEGRITY OF AIRFRAME A structural reassessment of the 737 airplane has been conducted under the requirements of Federal Aviation Administration (FAA) Advisory Circular 91-56 in accordance with Federal Aviation Regulation (FAR) 25.571, as amended in 1978, to ensure safe operation of 737 airplanes throughout their operational life. Table 1 is a summary of the inspections specified in Paragraph 1.E Compliance that are recommended for the detection of cracks in the STA 727 frame outboard chord prior to their reaching critical lengths. Failure to detect cracks prior to their reaching critical length may result in failure of the STA 727 frame outboard chord. Any cracked structure should be replaced prior to further flight unless specifically approved by your cognizant regulatory agency. Please report any discrepancies to Boeing Customer Support Engineering using the reporting system described in the addendum. **Table 1 - STA 727 Frame Outboard Chord at Stringer 18A Airplane Condition Compliance**  STA 727 Frame is in the as delivered condition. The inspection as given in 1.E., Compliance, Table 2 of this service bulletin replaces the local F-29 inspections. The F-29 inspections remain valid for all other areas of F-29 not inspected per Table 2. STA 727 Frame Outboard Chord replaced, but the STA 727 Frame Outboard Chord modification per this service bulletin has not been accomplished. The inspection as given in 1.E., Compliance, Table 3 of this service bulletin replaces the local F-29 inspections. The F-29 inspections remain valid for all other areas of F-29 not inspected per Table 3. STA 727 Frame Outboard Chord replaced and the STA 727 Frame Outboard Chord modification per this service bulletin has been accomplished. Service Bulletin 737-53-1088 Revision 1, dated May 25, 2006 contains the alternate F-29 inspections.

STA 727 Frame Outboard Chord is as delivered, but the STA 727 Frame Outboard Chord modification per this service bulletin has been accomplished. The F-29 inspections remain effective. An alternate inspection is not required for this configuration.**APPENDIX A: ADDENDUM** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 196 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT** Boeing requests that operators use the following Structural Significant Item (SSI) Reporting System to report any discrepancies that are found in accomplishing a Flight Safety Inspection. 1. Upon recognition of discrepancy, the following information should be telegraphed to Boeing: Heading: ATTENTION - SSI DISCREPANCY - SERVICE BULLETIN RELATED
- Service Bulletin number - Airplane serial number on which discrepancy was found - Identification of structural item found damaged - Flight cycles and hours on damaged item - Location and description of damage including direction and size - When discovered and inspection method used Send telegram through Boeing Field Service Representative or directly to: 737 Customer Support Engineering 2. An Operator's Follow-Up Report containing all available pertinent data, relative to the structural discrepancy, shall be sent to Boeing. A summary of the information that should be reported is shown in the DISCREPANT STRUCTURE REPORT form attached. Operators may use this form or any suitable alternative which contains the same information. 3. All data and reports dealing with the Flight Safety Inspection Program shall be submitted either through a Boeing Field Service Representative or directly to: The Boeing Commercial Airplane Group P.O. Box 3707 Seattle, Washington 98124-2207, USA Attn: 707/727/737 Service Engineering Director Org. M-7201 Mail Stop 2H-84 4. All reports will be reviewed promptly.**APPENDIX A: ADDENDUM** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 197 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

WALK-AROUND SCHEDULED MAINTENANCE 6. 5. 4. 3.

4A.

4B. AIRCRAFT DATA 2. DISCREPANT STRUCTURE REPORT

1.

STATION

MODEL A.T.A. INDEX REPORT DATA

NAME
IPC/DWG REF

COMPONENT FLIGHT CYCLES SINCE NEW COMPLETE THE FOLLOWING IF KNOWN AND DIFFERENT FROM SECTION 2: S/N

COMPLETED REPAIR DATA PLANNED

ACTION

SB
MPD
STRUCTURAL SIGNIFICANT ITEM NO.
SERVICE BULLLETINS INCORPORATED IN AREA OF DISCREPANCY

INSPECTION DATA

CORRESPONDING INSPECTION LEVELS

X 24291 ORIG. 3/84 (FRONT) 6A. WHEN DISCOVERED

OVERHAUL UNSCHEDULED SYMPTOM (FUEL/PRESS. LEAK . . . ) RELATED FLEET EXPERIENCE ACCIDENT INVESTIGATION SSID SERIES 50 6B. INSPECTION LEVEL

GENERAL VISUAL EXTERNAL SURVEILLANCE

DETAILED SPECIAL 6C. DETECTION METHOD

INTERNAL SURVEILLANCE VISUAL MAG. VISUAL DYE PENETRANT ULTRASONIC X-RAY LOW FREQUENCY EDDY CURRENT HIGH FREQUENCY EDDY CURRENT BORESCOPE MAGNETIC PARTICLE TAP TEST SOUND SMELL FEEL FUEL LEAK PRESS. LOSS SIDE 1

AIRLINE/AGENCY MONTH DAY YEAR REPORT NO.

MFG. SERIAL NO. FLIGHT HOURS SERIES TAIL NO.
FLIGHT CYCLES

COMPONENT FLIGHT HOURS SINCE NEW COMPONENT DATA (AS APPLICABLE AND AVAILABLE):

P/N
SRM REF

SINCE OVERHAUL
SINCE OVERHAUL

NO. SERVICE BULLETIN OF SERVICE BULLETIN APPLICABLE SECTION INCORPORATION DATE OF CYCLES AT INCORPORATION TOTAL FLIGHT HOURS AND

HOURS
HOURS
HOURS FLIGHTS
FLIGHTS FLIGHTS AD

OTHER (E.G., SDR, MRR) IPC SRM
SIIA SERIES 50 NO.

(COMPLETE KNOWN INFO., CHECK APPROPRIATE ITEMS FOR DISCREPANT STRUCTURE): CURRENT INSPECTION INTERVALS (FLIGHT)

SPECIAL/DIRECTED (AD, SB . . . ) REFERENCES ASSOCIATED WITH INSPECTION/REPAIR (SPECIFY NO., PAGE, FIGURE, ETC)W76755**APPENDIX A: ADDENDUM** June 30, 1994 Revision 2: May 25, 2006 737-53A1166 BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. 198 of 198 

### BOEING SERVICE BULLETIN 737-53A1166 **ALERT ALERT**

STRINGER Attach sketch, photos and text as required to describe defect and specific location. DISCREPANT STRUCTURE REPORT

X 2491 ORIG. 1/84 (BACK)

INSPECTED BY

ORIGINATED BY REPAIRED BY

DATE DISCREPANCY DESCRIPTION: 7. SIDE 2

associated discrepancies on the same airplane, related experience with this discrepancy on any airplane, and previous modification(s) to the discrepant structure. When applicable, give details of

TYPE OF DISCREPANCY: 7A.

LEAK DETACHED DENTED

DELAMINATED DEFORMED CRACKED CORRODED CONTAMINATED BENT

BURNED BUCKLED BROKEN

CLOGGED WORN STUCK OUT-OF-TOLERANCE MISSING LOOSE

ADJUSTED IMPROPERLY WRINKLED

SIZE OF DISCREPANCY: 7B. INCHES, OR CENTIMETERS
AREA

FINAL MEASUREMENT (IF DIFFERENT) CRACK LENGTH INITIALLY DETECTED DEPTH
DATE DATE X

7C. DISCREPANT PART: FRAME/BULKHEAD PRESSURE BULKHEAD FRAME AROUND OPENING WINDOW FORGING KEEL BEAM FLOOR

SPAR RIB

FLAP TRACK FAIRING WING CENTER SECTION WING DRY-BAY AREA/COMPT

LANDING GEAR BEAM JOINT/SPLICE LUG WELD BOND OPEN HOLE FASTENER HOLE CUTOUT

NOTCH/GROOVE DISCONTINUITY BASIC MATERIAL BUSHING PIN SKIN PLATE/PANEL CHORD NO.

STRUT/BRACE BEAM

LINK/ROD LONGERON FITTING BRACKET/SLIP STOP FASTENER ACCESS/LIGHTENING HOLE

7D. LOCATION OF DISCREPANT PART: GENERAL LOCATION (E.G., BILGE, UNDER GALLEY)

WING STA NO. BODY STA NO.

VERT STAB. STA HORIZ STAB. STA

NOSE LANDING GEAR MAIN LANDING GEAR WING LANDING GEAR BODY LANDING GEAR DOOR ACCESS PANEL RUDDER ELEVATOR AILERON FLAP SLAT SPOILER TAB (ALSO CHECK ABOVE) INTERIOR INBOARD LEFT FORWARD UPPER LEADING EDGE MIDDLE SPECIFIC LOCATION EXTERIOR OUTBOARD RIGHT AFT LOWER TRAILING EDGE SIDE NACELLE/PYLON COMPARTMENTW76756