### Commercial **Airplanes** 

# 757 Service Bulletin **ALERT Number: 757-52A0091**  Original Issue: March 09, 2010 ATA System: 5232 **SUBJECT:** DOORS - Main Cargo Door - Cam Latch and Latch Pin Inspection and Modification Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter.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

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 1 of 55 5.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 2 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 B. Concurrent Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 C. Reason . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 D. Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 I. Electrical Load Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 J. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1. Existing Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2. Data supplied with this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3. Installation Drawings Used in the Preparation of this Service Bulletin. . . . . . . . . . . . 21 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 L. Interchangeability and Intermixability of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1. Kits/Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2. Parts and Materials Supplied by the Operator. . . . . . . . . . . . . . . . . . . . . . . . 23 3. Parts Modified and Reidentified. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4. Parts Removed and Not Replaced . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 24 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 FIGURE 1: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION. . . . . . . . . 31 FIGURE 2: MAIN CARGO DOOR - LATCH PIN CROSS BOLT TORQUE MEASUREMENT. . . . . 34 FIGURE 3: MAIN CARGO DOOR - LATCH PIN EXTENSION MEASUREMENT. . . . . . . . . . . . 36 FIGURE 4: MAIN CARGO DOOR - CAM LATCH 1 AND CAM LATCH 2 INSPECTION . . . . . . . . 38 FIGURE 5: MAIN CARGO DOOR - LATCH PIN CROSS BOLT REPLACEMENT . . . . . . . . . . . 40 FIGURE 6: MAIN CARGO DOOR - CAM LATCH REPLACEMENT. . . . . . . . . . . . . . . . . . . 42 FIGURE 7: MAIN CARGO DOOR - LATCH PIN REPLACEMENT. . . . . . . . . . . . . . . . . . . . 45 FIGURE 8: MAIN CARGO DOOR - CAM LATCH REMOVAL AND INSPECTION . . . . . . . . . . . 47 FIGURE 9: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION. . . . . . . . . 49 FIGURE 10: MAIN CARGO DOOR - CAM LATCH AND LATCH PIN RIGGING . . . . . . . . . . . . . 51 FIGURE 11: MAIN CARGO DOOR - MAIN CARGO DOOR EDGE FLUSHNESS MEASUREMENT . . 54

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 3 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 4 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 757 Service Bulletin **ALERT Summary**  **Number: 757-52A0091** Original Issue: March 09, 2010 ATA System: 5232 **SUBJECT:** DOORS - Main Cargo Door - Cam Latch and Latch Pin Inspection and 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** Accomplishment of the inspections in this service bulletin will make sure the Main Cargo Door (MCD) cam latches are inspected for wear and the latch pins are inspected for migration. The inspections are necessary in order to find and replace worn cam latches, latch pins and latch pin attachment bolts. If not replaced, worn cam latches, latch pins and latch pin attachment bolts could lead to a failure of the cam latches and may result in a possible rapid decompression and potential separation of the cargo door from the airplane. Boeing has received one report from one operator that the MCD forward most cam latch on the forward center cam latch pair (cam latch number 3) broke during flight. The airplane that reported the broken cam latch had 20,000 flight hours and 9,500 flight cycles when the cam latch broke. The crew heard a loud noise coming from the MCD shortly after cruise. Upon landing, an inspection was performed and a cam latch was found broken. The broken cam latch mating latch pin was also found to have significant wear as evidenced by the loss of the plating on the surface that is normally in contact with the cam. The latch pin was also deformed approximately 0.05 inch in the area of the wear surface. The cause of the broken cam latch has been determined to be from a poorly rigged MCD. Although properly rigged per the original Aircraft Maintenance Manual (AMM) procedures, significant variation was allowed in the rigging dimensions. This variation can cause some of the latch pin/cam latch locations to have a significant preload placed on them during engagement and rotation of the cam latches during latching and unlatching operations. This preload is believed to have imparted a torque on the latch pin from the cam latch rotation during latching and unlatching operations. The torque transmitted to the latch pin is then believed to have caused the latch pin cross bolt to fail in shear. In addition, the cross bolt that attaches the latch pin had signs of corrosion on the fracture surfaces.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 5 of 55If the cross bolt fails, the latch pin could migrate either towards the cam latch or away from the cam latch. Latch pin migration towards the cam latch can cause significant interference with the mating cam latch leading to cam latch damage. In this case, the latch pin migrated into the cam latch and caused damage to the cam latch. The crack initiated at the damage site caused by the latch pin and then lead to the cam latch breaking. Latch pin migration away from the cam latch could cause disengagement from the cam latch, resulting in no load transfer between the cam latch and the mating latch pin and may not be noticed before critical conditions are exceeded. Accomplishment of the work given in this service bulletin will make sure the cam latches, latch pins and latch pins cross bolts are inspected and replaced if wear is found. The MCD will also be re-rigged to the requirements for door flushness, cam latch/latch pin concentricity, latch pin fitting forward/aft gap and shim thickness. Boeing Service Related Problem (SRP) 757-SRP-52-0088 is related to this service bulletin. **ACTION** Get access to the MCD. Do a detailed inspection of the cam latches and latch pins. Check the torque of the cross bolts in the latch pins. Measure the extension of the latch pins. Replace all alloy steel cross bolts through the latch pins with Corrosion Resistant Steel (CRES) cross bolts. Do a High Frequency Eddy Current (HFEC) or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracks. Replace any cracked or broken parts. Rig and check the MCD to the requirements for door flushness, cam latch/latch pin concentricity, latch pin fitting forward/aft gap and shim thickness. Perform post rigging inspections in accordance with this service bulletin. **EFFECTIVITY** 757-200CB, 757-200PF and 757-200 Special Freighter delivered under a Boeing Supplemental Type Certificate (STC) Airplanes. Refer to Paragraph 1.A.1., Airplanes for the list of affected airplanes. **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance. **INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspections and modifications given in this service bulletin.
**MANPOWER** Refer to Paragraph 1.G., Manpower.
**MATERIAL INFORMATION** Operator Supplied Parts/Materials. Refer to Paragraph 2.A., Material - Price and Availability

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 6 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 7 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 8 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# 757 Service Bulletin **ALERT Number: 757-52A0091**  Original Issue: March 09, 2010 ATA System: 5232 **SUBJECT:** DOORS - Main Cargo Door - Cam Latch and Latch Pin Inspection and 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 D624N001 Part 3 for Airplane Variable Number, Line Number, and Serial Number data. This service bulletin is for the airplanes shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** 757-200PF, 757-200CB and 757-200 Special Freighter delivered under a Boeing Supplemental Type Certificate (STC) Airplanes - 1

Airplane Models: 757-200, 757-200CB, 757-200PF **Group Variable Number**  1 NA201 - NA204 1 NA206 - NA213 1 NA215 - NA236 1 NC901 - NC951 1 NC971 1 NC973 - NC974 1 ND895

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 9 of 55**Group Variable Number**  1 NS601 - NS616 1 NT001 - NT009 2. Spares Affected
None. **B. Concurrent Requirements**
None. **C. Reason** Accomplishment of the inspections in this service bulletin will make sure the Main Cargo Door (MCD) cam latches are inspected for wear and the latch pins are inspected for migration. The inspections are necessary in order to find and replace worn cam latches, latch pins and latch pin attachment bolts. If not replaced, worn cam latches, latch pins and latch pin attachment bolts could lead to a failure of the cam latches and may result in a possible rapid decompression and potential separation of the cargo door from the airplane. Boeing has received one report from one operator that the MCD forward most cam latch on the forward center cam latch pair (cam latch number 3) broke during flight. The airplane that reported the broken cam latch had 20,000 flight hours and 9,500 flight cycles when the cam latch broke. The crew heard a loud noise coming from the MCD shortly after cruise. Upon landing, an inspection was performed and a cam latch was found broken. The broken cam latch mating latch pin was also found to have significant wear as evidenced by the loss of the plating on the surface that is normally in contact with the cam. The latch pin was also deformed approximately 0.05 inch in the area of the wear surface. The cause of the broken cam latch has been determined to be from a poorly rigged MCD. Although properly rigged per the original Aircraft Maintenance Manual (AMM) procedures, significant variation was allowed in the rigging dimensions. This variation can cause some of the latch pin/cam latch locations to have a significant preload placed on them during engagement and rotation of the cam latches during latching and unlatching operations. This preload is believed to have imparted a torque on the latch pin from the cam latch rotation during latching and unlatching operations. The torque transmitted to the latch pin is then believed to have caused the latch pin cross bolt to fail in shear. In addition, the cross bolt that attaches the latch pin had signs of corrosion on the fracture surfaces. If the cross bolt fails, the latch pin could migrate either towards the cam latch or away from the cam latch. Latch pin migration towards the cam latch can cause significant interference with the mating cam latch leading to cam latch damage. In this case, the latch pin migrated into the cam latch and caused damage to the cam latch. The crack initiated at the damage site caused by the latch pin and then lead to the cam latch breaking. Latch pin migration away from the cam latch could cause disengagement from the cam latch, resulting in no load transfer between the cam latch and the mating latch pin and may not be noticed before critical conditions are exceeded. Accomplishment of the work given in this service bulletin will make sure the cam latches, latch pins and latch pins cross bolts are inspected and replaced if wear is found. The MCD will also be re-rigged to the requirements for door flushness, cam latch/latch pin concentricity, latch pin fitting forward/aft gap and shim thickness.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 10 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**Boeing Service Related Problem (SRP) 757-SRP-52-0088 is related to this service bulletin. **D. Description** Get access to the MCD. Do a detailed inspection of the cam latches and latch pins. Check the torque of the cross bolts in the latch pins. Measure the extension of the latch pins. Replace all alloy steel cross bolts through the latch pins with CRES cross bolts. Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracks. Replace any cracked or broken parts. Rig and check the MCD to the requirements for door flushness, cam latch/latch pin concentricity, latch pin fitting forward/aft gap and shim thickness. Perform post rigging inspections in accordance with this service bulletin. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 838 757-200, 757-200CB, 757- 200PF **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. **Table 1: Initial (Pre-Rigging) Inspections of the Cam Latches and Latch Pins for the Main Cargo Door (MCD)**  **Repeat Interval (Not to Exceed)**  **Compliance Time Action**  **Condition**

- Within 330 flight cycles or 150 daysafter the original issue date of this service bulletin. (whichever occurs first) Do the following for all MCD cam latches and latch pins: Do a detailed inspection of the cam latches and latch pins in accordance with Accomplishment Instruction 3.B.1.b. And Torque the cross bolts in the latch pinsin accordance with Accomplishment Instruction 3.B.1.c. All airplanes

And Measure the extension of the latch pinsin accordance with Accomplishment Instruction 3.B.1.d.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 11 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 1: Initial (Pre-Rigging) Inspections of the Cam Latches and Latch Pins for the Main Cargo Door**  **(MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition** 

- Before further flight Replace all cracked or broken part(s) inaccordance with Accomplishment Instruction 3.B.2.a. Inspection Condition 1 - If the inspections revealone or more of the following: And 1. Cracked or broken cam latch(es) 2. Cracked or broken latch pin(s)
3. Broken latch pin cross bolt(s) Unless replaced with new parts, do aHFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2in accordance with Accomplishment Instruction 3.B.2.b. And Rig and check the MCD in accordance with Accomplishment Instruction 3.B.2.c. And Replace all alloy steel cross bolts through the latch pins with CRES crossbolts in accordance with Accomplishment Instruction 3.B.2.c.

- Within 330 flight cycles or 150 daysafter the initial inspection (whichever occurs first) Contact Boeing and provide a detaileddescription of the cam latch deformations for rework instructions and perform the applicable rework in accordance with Accomplishment Instruction 3.B.3.a.(a) Inspection Condition 2 - If the inspections revealone or more of the following:1. Local deformation of the cam latch lip. 2. Flaking of the chrome plating on the cam latch or latch pin. 3. Wear of the chrome plating down to the base material of the cam latch or latch pin. And Replace all cam latches and latch pinsin accordance with Accomplishment Instruction 3.B.3.b.(b) And 330 flight cycles or 150days (whichever occurs first) Within 330 flight cycles or 150 daysafter the initial inspection (whichever occurs first) Do a detailed inspection of the cam latches and latch pins in accordance with Accomplishment Instruction 3.B.3.c. And

- Within 3000 flight cycles or 24 months after the original issue dateof this service bulletin (whichever occurs first)Do a HFEC or alternate magnetic particle inspection of cam latch 1 and camlatch 2 in accordance with Accomplishment Instruction 3.B.3.d. And Rig and check the MCD in accordance with Accomplishment Instruction 3.B.3.e. And Replace all alloy steel cross bolts through the latch pins with CRES crossbolts in accordance with Accomplishment Instruction 3.B.3.e.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 12 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 1: Initial (Pre-Rigging) Inspections of the Cam Latches and Latch Pins for the Main Cargo Door**  **(MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition** 

- Before further flight Contact Boeing and provide a detailed description of the inspection findings(and photographs, if possible) in accordance with Accomplishment Instruction 3.B.4.a. Inspection Condition 3 - If the initial inspections reveal one or more signs of the following: 1. Corrosion of the cam latch or latch pin. 2. Gouges and/or scrapes in the cam latch or latch pin chrome platingor base material. 3. Deformations of the cam latch or latch pin.4. Any other damage not identified in Inspection Conditions 1 and 2. And Contact Boeing for additional inspection and/or repair instructions and perform applicable inspection and/or repair inaccordance with Accomplishment Instruction 3.B.4.b.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 13 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 1: Initial (Pre-Rigging) Inspections of the Cam Latches and Latch Pins for the Main Cargo Door**  **(MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition** 

- Within 330 flight cycles or 150 daysafter the initial inspection (whichever occurs first) Replace the latch pin in accordance with Accomplishment Instruction 3.B.5.a.(1). And Remove the mating cam latch and do a detailed inspection in accordance with Accomplishment Instruction 3.B.5.a.(2). Inspection Condition 4.1- If the latch pin extension is less that 0.84 inches or greater than 0.94 inches
And

- Within 3000 flight cycles or 24 months after the original issue dateof this service bulletin (whichever occurs first)Do a HFEC or alternate magnetic particle inspection of cam latch 1 and camlatch 2 in accordance with Accomplishment Instruction 3.B.5.a.(3). And Rig and check the MCD in accordance with Accomplishment Instruction 3.B.5.a.(4). And Replace all alloy steel cross bolts through the latch pins with CRES crossbolts in accordance with Accomplishment Instruction 3.B.5.a.(4). 330 flight cycles or 150days (whichever occurs first) Within 330 flight cycles or 150 daysafter the initial inspection (whichever occurs first) Do a detailed inspection of the cam latches and latch pins in accordance with Accomplishment Instruction 3.B.5.b.(1). And Inspection Condition 4.2- If the latch pin extension is between 0.84and 0.89 inches or between 0.91 and 0.94 inches

- Within 3000 flight cycles or 24 months after the original issue dateof this service bulletin (whichever occurs first)Do a HFEC or alternate magnetic particle inspection of cam latch 1 and camlatch 2 in accordance with Accomplishment Instruction 3.B.5.b.(2). And Rig and check the MCD in accordance with Accomplishment Instruction 3.B.5.b.(3). And Replace all alloy steel cross bolts through the latch pins with CRES crossbolts in accordance with Accomplishment Instruction 3.B.5.b.(3).

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 14 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 1: Initial (Pre-Rigging) Inspections of the Cam Latches and Latch Pins for the Main Cargo Door**  **(MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition**  330 flight cycles or 150days (whichever occurs first) Within 330 flight cycles or 150 daysafter the initial inspection (whichever occurs first)Do a general visual inspection in accordance with Accomplishment Instruction 3.B.6.a. And Inspection Condition 5 - If the inspections reveal no signs of damage,distress or incorrect rigging as described in Inspection Conditions 1 through 4. 3000 flights or 24months (whichever occurs first) Within 3000 flight cycles or 24 months after the initial inspection (whichever occurs first) Do a detailed inspection of the cam latches and latch pins in accordance with Accomplishment Instruction 3.B.6.b. AndDo a HFEC or alternate magnetic particle inspection of cam latch 1 and camlatch 2 in accordance with Accomplishment Instruction 3.B.6.c And

- Within 6000 flight cycles or 48 months after the original issue dateof this service bulletin (whichever occurs first) Rig and check the MCD in accordance with Accomplishment Instruction 3.B.6.d. And Replace all alloy steel cross bolts through the latch pins with CRES crossbolts in accordance with Accomplishment Instruction 3.B.6.d. (a) Boeing recommends the operator provide a detailed description of the cam latch deformations (including size and location, as well as the total number of flights the cam latch has been in service) so that Boeing has time to determine rework instructions and the operator has time to organize the resources needed to complete the changes within the applicable compliance period. (b) There is a possibility the cam latch or latch pin can be refinished with new chrome plating. Before a cam latch or latch pin can be reused, the operator must provide Boeing with a detailed description of the chrome damage, including size and location, as well as the total number of flights the cam latch or latch pin has been in service. Boeing will use this information to determine if the cam latch or latch pin can be refinished and reused.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 15 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 2: Repetitive Post-Rigging Inspections of the Cam Latches and Latch Pins for the Main Cargo**  **Door (MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition**  330 flight cycles or 150days (whichever occurs first) Within 330 flight cycles or 150 daysafter the MCD adjustment and check (whichever occurs first)Do a general visual inspection in accordance with Accomplishment Instruction 3.B.7.a.(1). And All airplanes

3000 flights or 24months (whichever occurs first) Within 3000 flight cycles or 24 months after the MCD adjustment and check (whichever occurs first) Do a detailed inspection of the cam latches and latch pins in accordance with Accomplishment Instruction 3.B.7.a.(2). And

6000 flights or 48months (whichever occurs first) Within 6000 flight cycles or 48 months after the MCD adjustment and check (whichever occurs first)Do a HFEC or alternate magnetic particle inspection of cam latch 1 and camlatch 2 in accordance with Accomplishment Instruction 3.B.7.a.(3).

- Before further flight Replace all cracked or broken part(s) inaccordance with Accomplishment Instruction 3.B.7.b.(1). Post-rigging InspectionCondition 1 - If the inspections reveal one or more of the following: And 1. Cracked or broken cam latch(es) 2. Cracked or broken latch pin(s)
3. Broken latch pin cross bolt(s) Unless replaced with new parts, do aHFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2in accordance with Accomplishment Instruction 3.B.7.b.(2). And Rig and check the MCD in accordance with Accomplishment Instruction 3.B.7.b.(3).

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 16 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 2: Repetitive Post-Rigging Inspections of the Cam Latches and Latch Pins for the Main Cargo**  **Door (MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition** 

- Within 330 flight cycles or 150 daysafter the post-rigging inspection (whichever occurs first) Contact Boeing and provide a detaileddescription of the cam latch deformations for rework instructions and perform the applicable rework in accordance with Accomplishment Instruction 3.B.7.c.(1).(a) Post-rigging InspectionCondition 2 - If the inspections reveal one or more of the following:1. Local deformation of the cam latch lip. 2. Flaking of the chrome plating on the cam latch or latch pin. 3. Wear of the chrome plating down to the base material of the cam latch or latch pin. And Replace all cam latches and latch pinsin accordance with Accomplishment Instruction 3.B.7.c.(2).(b) And 330 flight cycles or 150days (whichever occurs first) Within 330 flight cycles or 150 daysafter the post-rigging inspection (whichever occurs first) Do a detailed inspection of the remainingcam latches and latch pins in accordance with Accomplishment Instruction 3.B.7.c.(3). And

- Within 3000 flight cycles or 24 months after thepost-rigging inspection (whichever occurs first)Do a HFEC or alternate magnetic particle inspection of cam latch 1 and camlatch 2 in accordance with Accomplishment Instruction 3.B.7.c.(4). And Rig and check the MCD in accordance with Accomplishment Instruction 3.B.7.c.(5).

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 17 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Table 2: Repetitive Post-Rigging Inspections of the Cam Latches and Latch Pins for the Main Cargo**  **Door (MCD) Repeat Interval (Not**  **to Exceed) Compliance Time**  **Action Condition** 

- Before further flight Contact Boeing and provide a detailed description of the inspection findings(and photographs, if possible) in accordance with Accomplishment Instruction 3.B.7.d.(1). Post-rigging InspectionCondition 3 - If the inspections reveal one ormore signs of the following: And 1. Corrosion of the cam latch or latch pin. 2. Gouges and/or scrapes in the cam latch or latch pin chrome platingor base material. 3. Deformations of the cam latch or latch pin.4. Any other damage not identified in Inspection Conditions 1 and 2. Contact Boeing for additional inspection and/or repair instructions and perform applicable inspection and/or repair inaccordance with Accomplishment Instruction 3.B.7.d.(2).

(a) Boeing recommends the operator provide a detailed description of the cam latch deformations (including size and location, as well as the total number of flights the cam latch has been in service) so that Boeing has time to determine rework instructions and the operator has time to organize the resources needed to complete the changes within the applicable compliance period. (b) There is a possibility the cam latch or latch pin can be refinished with new chrome plating. Before a cam latch or latch pin can be reused, the operator must provide Boeing with a detailed description of the chrome damage, including size and location, as well as the total number of flights the cam latch or latch pin has been in service. Boeing will use this information to determine if the cam latch or latch pin can be refinished and reused.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 18 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT F. Approval**  This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin. **G. Manpower** The table below shows an estimate of the task hours necessary to do the inspections and modifications for each airplane. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **Elapsed Hours Task Hours**  **Number of Per- sons**  **Task**

0.25 0.25 1 Open Access 1.60 1.60 1 FIGURE 1 0.50 0.50 1 FIGURE 2 0.50 0.50 1 FIGURE 3 1.00(h) 1.00(h) 1 FIGURE 4 1.00 1.00 1 FIGURE 5 0.50(a) (f) (i) 0.50(a) (f) (i) 1(i) FIGURE 6 0.10(b) (g) 0.10(b) (g) 1 FIGURE 7 0.60(c) 0.60(c) 1 FIGURE 8 0.10(d) 0.10(d) 1 FIGURE 9 20.0 48.0 2-3 FIGURE 10 - FIG- URE 11 0.25 0.25 1 Close Access (e) (e) TOTAL FOR EACH AIRPLANE (a) Estimate is per cam latch requiring replacement.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 19 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT Elapsed Hours**  **Task Hours Number of Per-**  **sons Task**  (b) Estimate is per latch pin requiring replacement. (c) Estimate is per cam latch requiring inspection. (d) Estimate is per cam latch.(e) Total time required may vary depending upon conditions found during inspections. (f) Does not include time to match drill cam shaft. (g) Does not include time to match drill latch pin (h) Does not include NDI inspection time (i) Cam latch 4 will require 2 hours and a second person to remove. **H. Weight and Balance Changes Change in Moment**  **(Pound-Inches) Change in Weight**  **(Pounds) Airplane**  Negligible Negligible 757-200CB Negligible Negligible 757-200PF Negligible Negligible 757-200 Special Freighter
**I. Electrical Load Data** Not changed. **J. References** 1. Existing Data a. Boeing Service Related Problem (SRP) 757-SRP-52-0088 b. Standard Overhaul Practices Manual (SOPM) 20-20-01 c. 757 Aircraft Maintenance Manual (AMM) 52-32-00 d. 757 Illustrated Parts Catalog (IPC) 53-33-63-03 e. 757 Non-Destructive Testing (NDT) Manual Part 6, 51-00-12 or 51-00-21 2. Data supplied with this Service Bulletin
None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 20 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**3. Installation Drawings Used in the Preparation of this Service Bulletin
**Title Drawing Number**  DOOR INSTALLATION - MAIN CARGO 65-25326 LATCH MECHANISM INSTALLATION - MAIN CARGO DOOR 65-25339 SILL INSTL - LOWER, MAIN CARGO DOOR 143N8750 LATCH PIN FITTING - ASSY 65-67872 CAM - LATCH MECHANISM CARGO DOOR 69-23438 These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected**
1. Publications: **Chapter-Section Publication**  757 IPC 53-33-63-03 757 Illustrated Parts Catalog 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin.
**L. Interchangeability and Intermixability of Parts** Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 21 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 22 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  The operator can supply the parts and materials shown in Paragraph 2.C., Parts Necessary for Each Airplane. As an alternative, operators can purchase the parts from Boeing Spares. This service bulletin does not show the Boeing price and supply data. **B. Industry Support Information** Boeing warranty remedies are not available for the inspections and modifications given in this service bulletin. **C. Parts Necessary For Each Airplane** 1. Kits/Parts
None. 2. Parts and Materials Supplied by the Operator
**Notes Existing Part Number**  **Name QTY**  **Part Number / Specification**  (a) (b) NAS6603-24 BOLT, HEX HEAD, 160 KSI MIN TENSILE, LONG THREAD, A286, NONLOCKING 8 BACB30LM3-24 OR BACB30LM3-22 OR BACB30NF3-22 Parts are only needed if existing partcannot be reworked. 69-23438-2 Cam Latch 1

- 69-23438-2 143N8060-1 Cam Latch 2

- 143N8060-1 143N8027-2 Cam Latch 3

- 143N8027-2 69-23439-3 Cam Latch 4

- 69-23439-3 69-23439-4 Cam Latch 5

- 69-23439-4 143N8027-1 Cam Latch 6

- 143N8027-1 143N8060-2 Cam Latch 7

- 143N8060-2 69-23438-1 Cam Latch 8

- 69-23438-1 6-83137-2 Latch Pin

- 6-83137-2 (a) Refer to 757 Structural Repair Manual Chapter 51 for alternate fasteners. (b) BACB30LM3-24 and NAS6603-24 used if 143N8157-2 Clip Assembly is installed.
**NOTE:** Rubber Quicksetting Putty (G50673) is needed if the door rigging procedure per 757 AMM 52-32-00 20Sep2008 Revision is used. 3. Parts Modified and Reidentified
None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 23 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**4. Parts Removed and Not Replaced
None. **D. Parts Necessary to Change Spares**
None. **E. Special Tooling - Price and Availability**
None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 24 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT 3. ACCOMPLISHMENT INSTRUCTIONS** 
**A. GENERAL INFORMATION CAUTION:**  KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE.
**NOTE:** 1. The instructions identified in Paragraph 3.B., Work Instructions and the Figure(s) give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Obey all of the warnings and cautions given in the specified manual sections. 4. 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 – Torque limits to tighten nuts and bolts are in 757 SRM, Chapter 51 5. Use the approved fastener and process material substitutions in accordance with 757 SRM, Chapter 51. Alternate fasteners are listed in 757 SRM Chapter 51 and Boeing Drawing 65-88700. 6. If the length of any fastener specified in this service bulletin does not meet the installation standards in SRM Chapter 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards in SRM Chapter 51 may be used.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 25 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**7. A Detailed Inspection is defined as: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required. 8. A General Visual Inspection is defined as: A visual examination of an interior or exterior area, installation or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to 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. 9. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. **B. WORK INSTRUCTIONS** NOTE: It is important to do the following steps in the specified order. 1. Initial Inspections a. Get access to the Main Cargo Door. b. Do a detailed inspection of the cam latches and latch pins in accordance with FIGURE 1. c. Torque the cross bolts in the latch pins in accordance with FIGURE 2. d. Measure the extension of the latch pins in accordance with FIGURE 3. 2. Inspection Condition 1: If the inspections reveal one or more signs of the following: – Cracked or broken cam latch(es) – Cracked or broken latch pin(s) – Broken latch pin cross bolts

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 26 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**a. Replace cam latch in accordance with FIGURE 6, replace latch pin in accordance with FIGURE 7 and replace latch pin cross bolt in accordance with FIGURE 5. b. Unless replaced with new parts, do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracks in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. c. Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11, and replace all alloy steel cross bolts through the latch pins with CRES cross bolts in accordance with FIGURE 5. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging. 3. Inspection Condition 2: If the inspections reveal one or more signs of the following: – Local deformation of the cam latch lip – Flaking of the chrome plating on the cam latch or latch pin – Wear of the chrome plating down to the base material of the cam latch or latch pin a. Contact Boeing and provide a detailed description of the cam latch deformations for rework instructions and perform the applicable rework. b. Replace all cam latches and latch pins with signs of flaking of the chrome plating or wear down to the base material in accordance with FIGURE 6 and FIGURE 7. c. Do a detailed inspection of the cam latches and latch pins in accordance with FIGURE 1. Address the inspection findings as described in Inspection Conditions 1 through 4. d. Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracking in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. e. Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11, and replace all alloy steel cross bolts through the latch pins with CRES cross bolts in accordance with FIGURE 5. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging. 4. Inspection Condition 3: If the inspections reveal one or more signs of the following: – Corrosion of the cam latch or latch pin – Gouges and/or scrapes in the cam latch or latch pin chrome plating or base material – Deformations of the cam latch or latch pin – Any other damage not identified in Inspection Conditions 1 and 2. a. Contact Boeing and provide a detailed description of the inspection findings (and photographs, if possible). b. Contact Boeing for additional inspection and/or repair instructions and perform applicable inspection and/or repair.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 27 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**5. Inspection Condition 4: a. Inspection Condition 4.1 - If the latch pin extension is less than 0.84 inches or greater than 0.94 inches: (1) Replace the latch pin in accordance with FIGURE 7. (2) Remove the mating cam latch and do a detailed inspection in accordance with FIGURE 8. Address the inspection findings as described in Inspection Condition 1. (3) Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracking in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. (4) Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11, and replace all alloy steel cross bolts through the latch pins with CRES cross bolts in accordance with FIGURE 5. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging. b. Inspection Condition 4.2 - If the latch pin extension is between 0.89 and 0.84 inches or between 0.91 and 0.94 inches: (1) Do a detailed inspection of the cam latches and latch pins in accordance with FIGURE 1. Address the inspection findings as described in Inspection Conditions 1 through 3. (2) Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracking in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. (3) Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11, and replace all alloy steel cross bolts through the latch pins with CRES cross bolts in accordance with FIGURE 5. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging.
**NOTE:** Rigging for the latch pin will require it to be installed properly with an extension of 0.90 +/- 0.01 inches. A latch pin originally in condition 4.2 with no other discrepancies may be re-used by clocking the latch pin 90 degrees +/- 10 degrees from original position and match drilling a new cross bolt hole that provides the correct latch pin extension. Fill old cross bolt hole in pin with BMS 5-95 sealant and install pin with BMS 3-27 corrosion inhibiting compound. 6. Inspection Condition 5: If the inspections reveal no signs of damage, distress, or incorrect rigging as described in Inspection Conditions 1 through 4:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 28 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**a. Do a general visual inspection of the cam latches and latch pins in accordance with FIGURE 9. Address the inspection findings as described in Inspection Condition 1. b. Do a detailed inspection of the cam latches and latch pins in accordance with FIGURE 1. Address the inspection findings as described in Inspection Conditions 1 through 5. c. Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracking in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. d. Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11, and replace all alloy steel cross bolts through the latch pins with CRES cross bolts in accordance with FIGURE 5. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging. 7. Post-Rigging Inspections for Airplanes that have completed the Rig and Check of the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11: a. Post-Rigging Inspection of all airplanes: (1) Do a general visual inspection of the cam latches and latch pins in accordance with FIGURE 9. Address the inspection findings as described in Inspection Condition 1. (2) Do a detailed inspection of the cam latches and latch pins in accordance with FIGURE 1. Address the inspection findings as described in Inspection Conditions 1 through 3. (3) Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracking in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. b. Post-rigging Inspection Condition 1: If the post-rigging inspections reveal one or more of the following: – Cracked or broken cam latch(es) – Cracked or broken latch pin(s) – Broken latch pin cross bolt(s) (1) Replace cam latch in accordance with FIGURE 6, replace latch pin in accordance with FIGURE 7 and replace latch pin cross bolt in accordance with FIGURE 5. (2) Unless replaced with new parts, do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracks in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. (3) Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging. c. Post-rigging Inspection Condition 2: If the post-rigging inspections reveal one or more of the following:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 29 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**– Local deformation of the cam latch lip – Flaking of the chrome plating on the cam latch or latch pin – Wear of the chrome plating down to the base material of the cam latch or latch pin (1) Contact Boeing and provide a detailed description of the cam latch deformations for rework instructions and perform the applicable rework. (2) Replace all cam latches and latch pins with signs of flaking of the chrome plating or wear down to the base material in accordance with FIGURE 6 and FIGURE 7. (3) Do a detailed inspection of the cam latches and latch pins in accordance with FIGURE 1. Address the inspection findings as described in Inspection Conditions 1 through 3. (4) Do a HFEC or alternate magnetic particle inspection of cam latch 1 and cam latch 2 for signs of cracking in accordance with FIGURE 4. Address the inspection findings as described in Inspection Condition 1. (5) Rig and check the Main Cargo Door in accordance with FIGURE 10 and FIGURE 11. Refer to 757 AMM 52-32-00 Rev 20Sep2008 as an accepted procedure for MCD rigging. d. Post-rigging Inspection Condition 3: If the post-rigging inspections reveal one or more of the following: – Corrosion of the cam latch or latch pin – Gouges and/or scrapes in the cam latch or latch pin chrome plating or base material – Deformations of the cam latch or latch pin – Any other damage not identified in Inspection Conditions 1 and 2. (1) Contact Boeing and provide a detailed description of the inspection findings (and photographs, if possible). (2) Contact Boeing for additional inspection and/or repair instructions and perform applicable inspection and/or repair. 8. Put the airplane back to a serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 30 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 1: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 31 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 1: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION**  **(SHEET 2 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 32 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Detailed inspection of the cam latch.(a) 1 69-23438-2 Cam Latch 1 Inspect 1 Detailed inspection of the cam latch.(a) (b) 1 143N8060-1 Cam Latch 2 Inspect 2 Detailed inspection of the cam latch.(a) (b) 1 143N8027-2 Cam Latch 3 Inspect 3 Detailed inspection of the cam latch.(a) 1 69-23439-3 Cam Latch 4 Inspect 4 Detailed inspection of the cam latch.(a) 1 69-23439-4 Cam Latch 5 Inspect 5 Detailed inspection of the cam latch.(a) (b) 1 143N8027-1 Cam Latch 6 Inspect 6 Detailed inspection of the cam latch.(a) (b) 1 143N8060-2 Cam Latch 7 Inspect 7 Detailed inspection of the cam latch.(a) 1 69-23438-1 Cam Latch 8 Inspect 8 Detailed inspection of the latch pin.(a) 8 6-83137-2 Latch Pin Inspect 9(a) Look for signs of damage, distress or incorrect rigging. Some examples are: broken parts, cracks, deformations, flaking of the chrome plating, wear of the chrome plating down to the base material, corrosion, chips, gouges etc. (b) Cam Latches 2, 3, 6 and 7 are not chromed, therefore chrome flaking and chrome wear through cannot be assessed at these locations. Check for excessive wear.

**FIGURE 1: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 33 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 2: MAIN CARGO DOOR - LATCH PIN CROSS BOLT TORQUE MEASUREMENT**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 34 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) 8 NAS6603-24 Bolt Torque 1 (a) Make sure the cross bolt is capable of reacting a 15 pound-inch, +/- 1 pound-inch, torque from the head side of the bolt and also the nut side if no nutplate is used. The 15 pound-inch, +/- 1 pound-inch, torque value is approximately one-half of the installation torque and is used to give an indication of the integrity of the cross bolt.

**FIGURE 2: MAIN CARGO DOOR - LATCH PIN CROSS BOLT TORQUE MEASUREMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 35 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 3: MAIN CARGO DOOR - LATCH PIN EXTENSION MEASUREMENT**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 36 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Make sure the latch pin extends out 0.90 inch +/- 0.01 inch from the wear plate. 8 6-83137-2 Latch Pin Measure 1

**FIGURE 3: MAIN CARGO DOOR - LATCH PIN EXTENSION MEASUREMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 37 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 4: MAIN CARGO DOOR - CAM LATCH 1 AND CAM LATCH 2 INSPECTION**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 38 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  1 69-23438-2 Cam Latch 1 Remove / Keep 1 1 143N8060-1 Cam Latch 2 Remove / Keep 2 Do a HFEC inspection of cam latch 1 for signs of cracks in accordance with 757 NDT Part 6, 51-00-12 or 51-00-21.(a) (b) (c) 1 69-23438-2 Cam Latch 1 Inspect 3

Do a HFEC inspection of cam latch 2 for signs of cracks in accordance with 757 NDT Part 6, 51-00-12 or 51-00-21.(a) (b) (c) 1 143N8060-1 Cam Latch 2 Inspect

1 69-23438-2 Cam Latch 1 Install (Kept) 4 1 143N8060-1 Cam Latch 2 Install (Kept) 5 (a) Use a 0.080 inch diameter or smaller HFEC probe. Set the HFEC instrument to operate between 50 KHz and 75 KHz. If HFEC method indicates a crack, confirm a crack using magnetic particle inspection. Refer to SOPM 20-20-01 as an accepted procedure. (b) An optional magnetic particle inspection can be used. Refer to SOPM 20-20-01 as an accepted procedure. (c) HFEC indications can be confirmed using the magnetic particle inspection. If crack indications are found with HFEC and could not be confirmed with magnetic particle inspection, the HFEC crack indication is a non relevant indication due to chrome cracking.

**FIGURE 4: MAIN CARGO DOOR - CAM LATCH 1 AND CAM LATCH 2 INSPECTION (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 39 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 5: MAIN CARGO DOOR - LATCH PIN CROSS BOLT REPLACEMENT**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 40 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP** 

- 8 NAS6603-24 (BACB30NF3-22 optional) Bolt Remove 1
Install with BMS 3-27 corrosion inhibiting material 8 BACB30LM3-24 (BACB30LM3-22 optional) Bolt Install (New) 2

**FIGURE 5: MAIN CARGO DOOR - LATCH PIN CROSS BOLT REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 41 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 6: MAIN CARGO DOOR - CAM LATCH REPLACEMENT**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 42 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 6: MAIN CARGO DOOR - CAM LATCH REPLACEMENT**  **(SHEET 2 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 43 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Gusset must be removed to allow removal of cam latch number 4. - - Cam Latch Remove 1

(a) (b)

- - Cam Latch Install (New) 2(a) Use the original removed cam latch as a pattern/template to locate new cross bolt holes. Match hole angularity from existing cam latch. (b) Cam latch number 2 and cam latch number 7 only have two cross bolt holes.

**FIGURE 6: MAIN CARGO DOOR - CAM LATCH REPLACEMENT (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 44 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 7: MAIN CARGO DOOR - LATCH PIN REPLACEMENT**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 45 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP** 

- - 6-83137-2 Latch Pin Remove 1 Install latch pin wet with BMS 3-27 corrosion inhibiting material on faying surfaces. - 6-83137-2 Latch Pin Install (New) 2

**FIGURE 7: MAIN CARGO DOOR - LATCH PIN REPLACEMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 46 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 8: MAIN CARGO DOOR - CAM LATCH REMOVAL AND INSPECTION**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 47 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- - Cam Latch Remove 1 Detailed inspection of the cam latch for cracks. - - Cam Latch Inspect 2

(a)

- - Cam Latch Install (Kept) 3 (a) It is important to identify the Cam Latch part locations to ensure the parts are re-installed in correct locations. Cam latches installed incorrectly may seriously compromise proper door operation. (b) Gusset must be removed to allow removal of cam latch number 4.

**FIGURE 8: MAIN CARGO DOOR - CAM LATCH REMOVAL AND INSPECTION (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 48 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 9: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 49 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  General visual inspection of the cam latch.(a) 1 69-23438-2 Cam Latch 1 Inspect 1

General visual inspection of the cam latch.(a) 1 143N8060-1 Cam Latch 2 Inspect

General visual inspection of the cam latch.(a) 1 143N8027-2 Cam Latch 3 Inspect

General visual inspection of the cam latch.(a) 1 69-23439-3 Cam Latch 4 Inspect

General visual inspection of the cam latch.(a) 1 69-23439-4 Cam Latch 5 Inspect

General visual inspection of the cam latch.(a) 1 143N8027-1 Cam Latch 6 Inspect

General visual inspection of the cam latch.(a) 1 143N8060-2 Cam Latch 7 Inspect

General visual inspection of the cam latch.(a) 1 69-23438-1 Cam Latch 8 Inspect

General visual inspection of the latch pins.(a) 8 6-83137-2 Latch Pin Inspect 2

(a) Inspect for broken, cracked, missing or migrated parts.

**FIGURE 9: MAIN CARGO DOOR - CAM LATCHES AND LATCH PINS INSPECTION (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 50 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 10: MAIN CARGO DOOR - CAM LATCH AND LATCH PIN RIGGING**  **(SHEET 1 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 51 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 10: MAIN CARGO DOOR - CAM LATCH AND LATCH PIN RIGGING**  **(SHEET 2 OF 3)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 52 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (b)

- - Cam Latch Measure 1 (a) (b)

- 6-83137-2 Latch Pin Measure (c)

- - Latch Pin Fitting Measure (a) During rigging procedure the latch pin is not to contact the cam latch in any direction. (b) Wrap a single layer of 0.002 inch thick shim stock around latch pins 1 and 8. Use thin tape to keep shim in place. With latch pins 1 and 8 engaging their respective cam latches, and with latch pins 2 through 7 not contacting their respective cam latches in any direction, adjust if required, latch pin fittings 2 through 7 such that latch pins 2 through 7 axial centerlines and their respective cam latch axial centerlines are within the tolerance shown. (c) Adjust latch pin fittings by moving fitting on serrations and by adjusting shim thickness. On the two forward and two aft cam latches the Latch Pin Fitting/Cam Latch gap is 0.14 +/- 0.01 inch. On the four center cam latches the Latch Pin Fitting/Cam Latch gap is 0.08 +/- 0.01 inch. Make sure the maximum allowed shim thickness of 0.20 inch is not exceeded.

**FIGURE 10: MAIN CARGO DOOR - CAM LATCH AND LATCH PIN RIGGING (SHEET 3 OF 3)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 53 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT FIGURE 11: MAIN CARGO DOOR - MAIN CARGO DOOR EDGE FLUSHNESS MEASUREMENT**  **(SHEET 1 OF 2)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 54 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for this figure.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  Hold scale 90 degrees to door edge. Make sure the MCD lower edge and lower corner flushness are within the tolerance shown. - - Main Cargo Door Measure 1

**FIGURE 11: MAIN CARGO DOOR - MAIN CARGO DOOR EDGE FLUSHNESS MEASUREMENT (SHEET 2 OF 2)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: March 09, 2010 757-52A0091 55 of 55 **BOEING SERVICE BULLETIN 757-52A0091 ALERT**  **ALERT**