### Tx Ltr SB 84-52-77 Page 1 of 2 Revision ‘C’ 05 Jun 2014 RR DHC-8 (DASH 8) SERVICE BULLETIN 84-52-77
Doors - Forward Passenger Door - Step Assembly - Special Inspection and Rectification This page transmits Revision ‘C’ of Service Bulletin 84-52-77, pages 1 thru 10, dated 05 Jun 2014. This service bulletin is re-issued in its entirety for the reasons that follow: - the Compliance section is revised to include the AD revision number - the Description section is revised to include an inspection thru the end panel assembly - the Material - Price and Availability section is revised to correct a typographical error - the References section is revised to convey the latest revision of the service bulletin, engineering documenta tion, attached Appendix A and AD - the ACCOMPLISHMENT INSTRUCTIONS - Procedure section is revised to add Figure 3, which provides the location of the end panel assembly - the ACCOMPLISHMENT INSTRUCTIONS - Procedure section is revised to add the reference to new Figure 1, which shows the location of the end panel assembly - the Close Out section is revised to convey the latest reviison - Figure 1, sheets 1 and 2 added
Remove the previsious revision of Service Bulletin 84-52-77 with its attached VSB and Bombardier Appendix A, and replace with attached. Previous issue(s) of Service Bulletin 84-52-77: Initial issue - Pages 1 thru 16 dated 31 Aug 2012 Revision A - Pages 1 thru 6 dated 24 Apr 2013 Revision B - Pages 1 thru 8 dated 31 Oct 2013

## SERVICE BULLETIN 84-52-77

Tx Ltr SB 84-52-77 Page 2 of 2 Revision ‘C’ 05 Jun 2014 RR 

## This Page Intentionally Blank 1

# D

S.B. 84-52-77

Page 1 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR 

# SERVICE BULLETIN
Customer Support

ATA SYSTEM: 5211 NUMBER: 84-52-77 

## BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS SERVICE BULLETIN TO BE PARTICULARLY SIGNIFICANT AND URGE OPERATORS TO PROMPTLY EVALUATE THE CONTENTS

SUBJECT: Doors - Forward Passenger Door - Step Assembly - Special Inspection and Rectification

1. PLANNING INFORMATION
A. Effectivity Aircraft Affected: In-Service: DHC-8 Aircraft Models 401 and 402 Serial Numbers 4001, 4003 thru 4393, with the airstair door step assemblies (part number 85217008-001) containing serial numbers SAC0001 thru SAC0016 and SAC0018 thru SAC0097 installed. Also include any part in this range that may have a sufffix after the number.
NOTE : All Aircraft Serial Numbers 4394 and subsequent have been addressed in production.

NOTE: The instructions in this Service Bulletin are only applicable to the systems and parts installed at the time of delivery on the aircraft or as changed by Bombardier Aerospace Service Bulletin(s). Before you do this bulletin, examine all STC or equivalent action changes to make sure this bulletin can be completed.

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 2 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR Spares Affected: The following is a list of spares affected by this change. Review spares and procurement systems to determine the existence of any listed parts. See Paragraph 2.D., Existing Parts Accountability, for disposition.

Part Number Description 85217008-001 Step Assembly B. Reason Problem: When bonding the airstair steps to the airstair sidewalls it is possible that the epoxy compound at the mortise and tenon stair-to-sidewall joints may have been omitted. This can cause the sealant applied between the airstair steps and the airstair sidewalls to crack and/or to make a clearance at the joint where moisture can get in. The latter can have an effect on the structural integrity of the steps and the passenger exit. Solution: This service bulletin provides the instructions to do an inspection of the airstair step assembly to record the serial number, or perform an electronic tap test inspection if a serial number cannot be found, and determine if a replacement of the airstair step assembly is necessary. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: - aircraft is put into standard configuration for maintenance - aircraft electrical power is removed - the nose landing gear lock is engaged - the main landing gear lock pins are inst alled through each main gear and main gear door mechanism - access is gained to the airstair door Part A - Inspection of the Airstair Step Assembly : - the aft sidewall of the airstair step assembly is inspected through the end panel assembly and the serial number is recorded. A boroscope may be required. - if the serial number is not found through the end panel assembly, the stair tread light assembly or assemblies are removed. - the aft sidewall of the airstair step assembly is inspected through the light assembly recess and the serial number is recorded. A boroscope may be required.

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 3 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR NOTE: Sealant cracking between the affected airstair steps and airstair sidewall is expected. No action is necessary to rectify this condition. - if the serial number is not found through the end panel assembly or the light assemblies, the door shell or the airstair step assembly is removed to help find and record the serial number. - if the serial number is found and is not in the affected range, the airstair step assembly is returned to serviceble use. - if the serial number is found and is in the affected range, then the affected airstair step assembly must be replaced as instructed in the attached Short Brothers Service Bulletin D8400-52-0011. - if the serial number is not found, perform an electronic tap test, as instructed in the attached Bombardier Appendix A to confirm the existence of epoxy compound - if the existence of epoxy compound is confirmed, reidentify the airstair step assembly as instructed in the attached Bombardier Appendix A - a record is made in the applicable logbook(s) that the inspection has been done - close out. - if the existence of epoxy compound is not confirmed, then the affected airstair step assembly must be replaced as instructed in the attached Short Brothers Service Bulletin D8400-52-0011. - a record is made in the applicable logbook(s) that the inspection has been done - close out. Part B - Replacement of the Airstair Step Assembl y: - a replacement airstair step assembly is installed on the airstair door assembly. - the airstair door assembly is installed o n the aircraft as instructed in the attached Short Brothers Service Bulletin D8400-52-0011. - a record is made in the applicable logbook(s) that the inspection and replacement have been done. - close out.

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 4 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR D. Compliance Bombardier Inc. recommends incorporation of this service bulletin at the earliest opportunity unless otherwise directed by the operator’s airworthiness authority. Transport Canada Airworthiness Directive CF-2013-20R1. E. Approval The technical content of this service bulletin has been approved under the authority of the Transport Canada Civil Aviation (TCCA) Design Approval Organization No: DAO #93-Q-02. This Service Bulletin does not affect Airworthiness Limitations (AWLs) or Damage Tolerance Inspections (DTIs). F. Manpower Part A - Inspection It will take an estimated 4 man-hours to complete the inspection of the airstair step assembly. The breakdown of man -hours is shown in the table that follows: TASK MAN-HOURS Job Set-Up 1.00 Procedure in Part A 1.50 Test / RTS 1.00 Close-Out 0.50 For any on-site labor assistance, please speak with a Fleet Services representative for a quote. The Fleet Services group can be contacted via the Q Series Technical Help Desk by telephone at 416-375-4000 or email at : thd.qseries@aero.bombardier.com PART B - Rectification It will take an estimated 9 man-hours to complete the rectification in this service bulletin. The breakdown of man -hours is shown in the table that follows: TASK MAN-HOURS Job Set-Up 0.50 Procedures in Part B 7.00 Test / RTS 1.00 Close-Out 0.50

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 5 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR G. Material - Price and Availability The affected range is serial numbers SAC0001 thru SAC0016 and SAC0018 thru SAC0097. Replacement airstair step assembly (part number 85217008-001) is available through the Service Bulletin Support team. For any terms and conditions, Operators should contact this group at: Facsimile: (416) 375-3060 Telephone: (416) 375-3920 e-mail address: sbkits@aero.bombardier.com For airstair door assembly replacement, refer to the attached Short Brothers Service Bulletin D8400-52-0011. H. Tooling - Price and Availability None I. Weight and Balance None
J. Electrical Load Data Not affected
K. Publications Affected None
L. References Revision ‘C’ of this service bulletin was prepared to the engineering drawings and related data that follows: Maintenance Manual PSM 1-84-2

................................ Structural Repair Manual PSM 1-84-3

............................ Dash 8 Illustrated Parts Catalogue PSM 1-84-4

.................... PCA 43429 Revision -- (for internal reference only)

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 6 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR Short Brothers Service Bulletin D8400-52-0011 Bombardier Appendix A Transport Canada Airworthiness Directive CF-2013-20R1
2. MATERIAL INFORMATION A. Parts Required Per Aircraft Refer to the attached Short Brothers Service Bulletin D8400-52-0011. Refer to Bombardier Appendix A. B. Parts Required to Modify Spares None C. Special Tools and Equipment Required Portable electronic tap tester Mitsui Woodpecker WP-632AM or WP-632M. Calibration test standard (CTS) EXBD400-51325-101 or similar test piece (ex: DHC29051001). D. Existing Parts Accountability Refer to the attached Short Brothers Service Bulletin D8400-52-0011. 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set-Up (1) Placard and select all aircraft electrical power to OFF, if necessary. Obey all relevant WARNINGS and CAUTIONS (refer to AMM TASK 24-00-00-861-802 and AMM TASK 24-00-00-910-801). (2) Make sure that lock pins are installed through each main gear and main gear door mechanism. (3) Make sure the nose gear ground lock is engaged. (4) Access is gained to the airstair door. B. Procedure (1) Do the inspection of the airstair step assembly, as instructed in the attached Short Brothers Service Bulletin D8400-52-0011. Refer to Figure 1 for inspection through the end panel assembly.

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 7 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR NOTE: Sealant cracking between the affected airstair steps and airstair sidewall is expected. No action is necessary to rectify this condition. (2) if the serial number is not in the affected range, do the Close Out section of this service bulletin. (3) if the serial number is in the affected range, do the replacement of the airstair step assembly, as described in the attached Short Brothers Service Bulletin D8400-52-0011, and then do the Close Out section of this service bulletin.
NOTE: Before installing the replacement airstair step assembly, check that its serial number is not in the affected range. Refer to section 1. G. Material - Price and Availability of this service bulletin. (4) if the serial number is not found, or is illegible, do an electronic tap test to determine the existence of the epoxy compound between the mortise and tenon joints, as instructed in the attached Bombardier Appendix A. (5) if the existence of the epoxy compound is confirmed, reidentify the airstair step assembly, as instructed in the attached Bombardier Appendix A, then do the Close Out section of this service bulletin. (6) if the existence of the epoxy compound is not confirmed, do the replacement of the airstair step assembly as instructed in Part B of the ACCOMPLISHMENT INSTRUCTIONS of the attached Short Brothers Service Bulletin D8400-52-0011, then do the Close Out section of this service bulletin.
C. Close Out (1) Remove all tools and equipment from the work area. (2) On completion of this service bulletin, make an entry that conforms to local regulatory requirements in the appropriate logbooks: “Service Bulletin 84-52-77 Revision C Doors - Forward Passenger Door - Step Assembly - Special Inspection and Rectification accomplished”.

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 8 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR Inspection Through the End Panel Assembly - FWD Passenger Door Figure 1 (Sheet 1)

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 9 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR Inspection Through the End Panel Assembly - FWD Passenger Door Figure 1 (Sheet 2)

## SERVICE BULLETIN 84-52-77

S.B. 84-52-77 Page 10 of 10 31 Aug 2012 Revision ‘C’ 05 Jun 2014 RR 

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# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 2 (2) Substantiation Investigations have identified insufficient bonding between the step tenon and sidewall mortice joints. (3) Objective This Service Bulletin gives instructions how to replace those Step Assemblies that have been assembled incorrectly. (4) Effect of Bulletin on: (i) Operation
Not affected (ii) Maintenance
Not affected. (iii) Overhaul
Not affected. (iv) Repair Scheme
Not affected. (v) Interchangeability
Not affected. (vi) Fits and Clearances
Not affected. C. Description Part A Inspection of the Step Assembly:

 The aft sidewall of the Step Assembly is inspected through the end panel assembly and the serial number is recorded. A boroscope may be required to see the serial number.

 If the serial number is not found through the end panel, then the stair tread light assembly or assemblies are removed as required (AMM TASK 33-21-01-000- 801).

 The aft sidewall of Step Assembly is inspected through the light assembly recess and the serial number is recorded. A boroscope may be required to see the serial number.

 If the serial number is not found through the light assemblies, then the door shell or the Step Assembly is removed to help find and record the serial number.

# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 3  If the serial number is in the affected range, then the step assembly must be replaced as instructed in PART B of this Service Bulletin. Note: Only serial numbers with the “SAC” prefix are affected and require action as instructed in this service bulletin.

 If the serial number is still not found, then the airstair step assembly will require an electronic tap test to determine the existence of epoxy compound. Refer to the BA Service Bulletin 84-52-77.

 If the existence of epoxy compound is confirmed, then refer to the BA Service Bulletin 84-52-77 for re-identification procedures.

 If the existence of epoxy compound is not confirmed, then the affected airstair step assembly must be replaced as instructed in PART B of this service bulletin.

 A record is made in the applicable logbook(s) that PART A has been done. Part B Replacement of the Step Assembly:

 A replacement Step Assembly is installed on the Airstair Door Assembly if the Serial number is in the affected range (AMM TASK 52-11-01-400-801).

 The Airstair Door Assembly is installed on the aircraft (AMM TASK 52-11-00- 400-801).

 A record is made in the applicable logbook(s) that PART A and PART B have been done. D. Compliance It is recommended that this Service Bulletin be done at the operator’s earliest convenience. E. Approval The design content conveyed by this Service Bulletin has been approved by the Design Approval Representative for Transport Canada at Bombardier Inc. F. Manpower Part A Approximately 1.0 man-hour will be required to inspect the Step Assembly and record the serial number. Part B Approximately 7.0 man-hours will be required to complete the replacement of the Step Assembly. This estimate is for direct labour performed by an experienced crew and it does not include set-up, planning, familiarisation, cure time, part fabrication, tool acquisition, lost time or the time taken to gain access to the affected area.

# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 4 G. Material - Price and Availability The part detailed in Paragraph I.A is available from Bombardier Aerospace. Refer to the BA cover bulletin for price and availability.

Part Number Description Price (US$) Delivery

85217008-001 Step Assembly
Part may be obtained by submitting a purchase order, specifying the Step Serial Number to: Bombardier Aerospace Customer Accounts Services Team (Mail Stop N11---32) 123 Garratt Boulevard Downsview Ontario Canada, M3K 1Y5 H. Tooling - Cost and Availability Not applicable. I. Weight and Balance
Not affected. J. Electrical Load Data
Not affected.
K. Publications Affected
None L. References
Aircraft Maintenance Manual PSM 1-84-2 Structural Repair Manual PSM 1-84-3 Illustrated Parts Catalog PSM 1-84-4

# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 5 II. MATERIAL INFORMATION A. Parts Required Per Aircraft

. Part Number Quantity Per Aircraft Description Remarks 85217008-001 1 Step Assembly NOTE: This Service Bulletin is self-con tained (illustrated). No drawings will be supplied. B. Parts Required to Modify Spares.
None. C. Special Tools and Equipment Required.
None D. Existing Parts Accountability. Retain for future rework the removed Step Assemblies found to be in the affected range stated in Section I.A. of this Service Bullet in. Contact the appropriate address that follows:
Bombardier Aerostructures and Services Bombardier Customer Services 229-333 Doagh Road Dallas, MRO Newtownabbey, Belfast 4039 Rock Quarry BT36 6XA Suite 600 Northern Ireland, UK Dallas, Texas Attn: Spares Sales TX 75211 Tel: +44 2890 733700 USA Fax: +44 2890 733839 Tel: 214 331 9400 E Mail: bfs_spares_sales@aero.bombardier.com Fax: 214 331 9401

# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 6 III. ACCOMPLISHMENT INSTRUCTIONS PART A Inspection of the Airstair Step Assembly
1. Inspect for the serial number on the aft side panel through the cut-outs in the composite closing panel part number 85217027. 2. If the serial number cannot be found or if the access is not sufficient, then remove the light assembly from the upright on the bottom stair tread. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 33-21-01, TASK 33-21-01-000-801. NOTE: Move the light assembly to the side to permit inspection of the inner sidewall. It is not necessary to disconnect the light assembly. 3. A boroscope may be required to inspect the aft side wall of the Step Assembly. Note the serial number. Refer to Picture 1 for serial number location and Picture 2 for method of inspection.
4. If the serial number cannot be found through the light assembly hole on the bottom stair tread, then remove the other light assemblies as required to permit inspection at alternative locations. Refer to Picture 1.
5. If the serial number cannot be found by removal of the light assemblies then do as follows:

 Remove the Door Shell. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52- 11-06, TASK 52-11-06-000-801. Or

 Remove the Step Assembly from the Airstair Door Assembly. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-01, TASK 52-11-01-000-801.
6. If the serial number is still not found, then the airstair step assembly will require an electronic tap test to determine the existence of epoxy compound. Refer to the BA Service Bulletin 84-52-77. Do as follows:

 If the existence of epoxy compound is confirmed, then refer to the BA Service Bulletin 84-52-77 for re-identification procedures. Continue with step 6 through step 10.

 If the existence of epoxy compound is not confirmed, then the affected airstair step assembly must be replaced with an airstair step assembly that is not in the affected range as instructed in PART B of this Service Bulletin. 7. Re-install the light assembly or assemblies. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 33-21-01, TASK 33-21-01-400-801. 8. If the serial number is in the affected range then do PART B of this Service Bulletin. Note: Only serial numbers with the “SAC” prefix are affected and require action as instructed in this service bulletin.

# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 7 9. Re-install the Door Shell if applicable. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-06, TASK 52-11-06-400-801. 10. Re-install a Step Assembly to the Airstair D oor Assembly if applicable. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-01, TASK 52-11-01-400-801. 11. Make an entry in the applicable logbook(s) that conforms to the local regulatory requirements. Refer to PART B, para 7 of this Service Bulletin.
PART B Replacement of the Airstair Step Assembly 1. Remove the Airstair Door Assembly from the aircraft. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-00, TASK 52-11-00-000-801. 2. Remove the Step Assembly from the Airstair Door Assembly. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-01, TASK 52-11-01-000-801. 3. Install a replacement Step Assembly to the Airstair Door Assembly if the Serial number is found to be in the affected range stated in Section I.A. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-01, TASK 52-11-01-400-801. 4. Install the Airstair Door Assembly on the aircraft. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-00, TASK 52-11-00-400-801. 5. Adjust the Airstair Door Assembly. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-00, TASK 52-11-00-820-801. 6. Do a functional test of the Airstair Door Assembly. Refer to the Dash 8 Aircraft Maintenance Manual Chapter 52-11-00, TASK 52-11-00-720-801. 7. On incorporation of this Service Bulletin, make an entry that conforms to local regulatory requirements in the applicable logbook(s). Enter component serial numbers if applicable. Enter this Service Bulletin number Part A or Part A and Part B only after complete and functional incorporation of all work defined in this Service Bulletin is embodied.

# SERVICE BULLETIN D8400-52-0011

Basic – July 25, 2012 Revision A - December 12, 2012 Revision B - October 22, 2013 

# D8400-52-0011
Revision C - February 26, 2014 Page | 8 

### Remove light assemblies as required to inspect for the serial number at View A, B or C

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### Bombardier Appendix A SB 84-52-77

1 

### ELECTRONIC TAP TEST OF THE DASH 8/400 AIRCRAFT STEP ASSEMBLY A THE MORTISE AND TENON JOINTS BETWEEN SIDEWALLS AND STEP This Appendix A defines a procedure for inspec tion of the Dash8/400 airstair door. This procedure consists of performing an electroni c tap test inspection to confirm the existence of epoxy compound in the mortise

1. AREA DESCRIPTION Refer to Figure 1 A. The airstair door walls are made of Aramid fabric and fibrous Nylon honeycomb core. A DÉCOR LAM layer is applied on each side of the wall B. The airstair door steps are m ade of glass fiber and fibrous Nylon honeycomb core C. The airstair door steps are assemb led with the walls by mortise and tenon joint. D. The tenons may have been install ed with or without epoxy compound. NOTE: If the tenons were installe d with epoxy compound they will act as Inserts. The local stiffness at this location will be greater than the surrounding areas

2. PURPOSE A. To determine if the door step ten ons have been installe d with or without epoxy compound 3. ACCESS A. Access to the inspection area is from the outside of the aircraft 4. INSPECTION METHOD A. Electronic tap testing 5. EQUIPMENT REQUIRED A. The equipment that follo ws was used in the devel opment of this procedure 1) Portable electronic tap tester Mi tsui Woodpecker WP-632AM made by Cadex Japan. Refer to Figure 2 sheet 1 NOTE: WP-632 electronic tap test er Mitsui Woodpecker with WP-632M (exter nal monitoring unit) made by C adex Japan can also be used 2) Calibration test standard (CTS ) Bombardier EXBD400-51325-101. Refer to Figure 2 sheet 2 NOTE: Similar test piece with known defect (ex:DHC29051-001) can also be used

### Bombardier Appendix A SB 84-52-77

2 

### 3) Noncorrosive, nonabrasive and easily removable marker pen to mark the location of the inspection area . The pen must not contain chlorine, lead or graphite 6. PERSONNEL QUALIFICATION A. Personnel who do this inspection mu st be familiar with t he structure being inspected and the use of the electronic tap tester. Personnel must read the general information on electronic t ap testing before the inspection begins (refer to the NDTM (PSM 1-84- 7A) Part 1 51-00-05, task 51-00-05- 910-801
7. PREPARATION A. Ensure that the surface of t he inspection area is clean and dry B. Use the marker pen and mark the loca tion of the inspection area as shown in Figure 1 C. Install batteries in the instrument and make sure that are fully charged D. Check the hammer head and feet for excessive wear and cleanliness. E. Replace the parts if excessive wear is found. 8. INSTRUMENT VERIFICATION NOTE: If the instrument does not pass th e verification, the instrument cannot be used for inspection NOTE: At all times the instrument hammer head must be 90 degrees +/- 10 degrees to the surface being tapped A. The instrument verification that follows was performed with the electronic tap tester WP632AM, The verification with electronic tap tester WP 632 and WP-632M is similar. 1) Press the POWER button to turn the power on 2) Press the DEBOND INSERT bu tton to select the insert mode 3) Press the AVE_SET button to se t the average (AVE) number of taps to 2 and the tap frequency to 8 taps/sec 4) Put the hammer feet on the CTS ov er the defect. Refer to Figure 2 5) Press and hold the blue memory switch while you move the instrument slightly on the surf ace of the CTS to acquire the standard reference value. The value will be between 38 and 41 6) Once the standard reference val ue is acquired the READY LED will be green. 7) Press the START/STOP button to start the scan and slightly move the instrument away from the defect while scanning 8) When the instrument is mo ved away from the defect

 the buzzer will come on

### Bombardier Appendix A SB 84-52-77

3 

###  the combination LED that s hows the presence of stiffer structure will turn red

 The measured value will be between 32 and 36 9) Press the START/STOP button to stop the scan. 9. INSPECTION A. Make sure that the surface to be inspected is clean and dry B. Make sure that the instrument is set up as in Para. 8 - Instrument Verification C. Put the hammer head perpendicular to t he inspection area at the location shown just outside the step tr ace (Refer to Figure 1) D. Press and hold the memory switch to acquire a standard reference value. E. Once the standard reference value has been memorized by the instrument the Ready LED will be green F. Press the Start /St op Button to start scanning G. Do a scan toward the mortise/te non joint shown in Detail A only 1) If the location tapped alarms the bu zzer and the combination of LEDs showing Insert (stiffer structure) then the step tenon is installed with epoxy compound 2) If the location tapped does not alarm the buzzer and combination LEDs then the tenons are not installed wit h epoxy compound. The steps are only sealed at the joint 10. INDICATION EVALUATION A. If the insert (tenon) cannot be detect ed then the tenon was not installed with epoxy compound 11. ACCEPTANCE/REJECTION CRITERIA A. If tenon joints are confirmed to be installed with epoxy compound then the step assembly is not affected by the SB. Reidentify the step assembly as SB 84-52-77- PASS. B. If tenon joints are not installed with epoxy, then do the replacement of the airstair step assembly as directed in Part B of the ACCOMPLISHMENT INSTRUCTION of the attached Short Br others Service Bulletin D8400-52- 0011. 12. REPORTING N/A

### Bombardier Appendix A SB 84-52-77

4 B B A Outline of door steps Mortises at each step Typ

FWD wall

Detail A Mark the outline of the step as shown View looking aft on forward wall of step assembly

Figure 1 Sheet 1

### Bombardier Appendix A SB 84-52-77

5
NOTE: Drawing not to scale Figure 1 Sheet 2

### Bombardier Appendix A SB 84-52-77

6 Equipment Figure 2 sheet 1 INSERT

WP- 632AM

### Bombardier Appendix A SB 84-52-77

7 EXBD400-51325-001 calibration test standard During instrument verification take average value here

Equipment Figure 2 sheet 2Jan 2009 

### SERVICE BULLETIN (SB) --- RECORD OF INCORPORATION --- Q SERIES DASH 8 AIRCRAFT To: CMDB Focal Facsimile: (1) 416 375 4538 E --mail: cmdb.requests@aero.bombardier.com

From: Company: Phone: Extn: Facsimile: Date:

E --mail: 

### The data that you provide below will help us record the incorporation of this ModSum and the aircraft effectivity in the maintenance manual. Operator: Service Bulletin:

__________________ 

### Revision:

_________ Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed:
Aircraft Serial Number: Model Number: Date Bulletin Completed: 

# Fax this sheet to (1) 416 375 4538 or Email PDF to: 

# cmdb.requests@aero.bombardier.comFeb 2009 

### SERVICE BULLETIN (SB) --- COMMENT SHEET --- Q SERIES DASH 8 AIRCRAFT

To: SB Focal (Toronto), Bombardier Aerospace Commercial Aircraft Phone: (1) 416 375 4078 Facsimile: (1) 416 375 4538 E --mail: syed.rizvi@aero.bombardier.com

From: Company: Phone: Extn: Facsimile: Date:

E --mail: 

### Select appropriate box(es) and add comments or suggestions you would like us to know that may enhance the quality of our service bulletins. Service Bulletin: Revision: ModSum: 1. PLANNING INFORMATION V Effectivity V Reason V Description V Compliance V Approval V Manpower V Material V Weight and Balance V Electrical Load V Tooling V References V Publications Affected
2. MATERIAL INFORMATION V Kit Content V Special Tools/Equipment V Parts to Modify Spares V Consumables V Disposition of Existing Parts V Other

3. ACCOMPLISHMENT INSTRUCTIONS V Job Set ---Up V Procedure V Close---Out V Test V Illustration(s) V Other 4. COMMENTS, REMARKS, SUGGESTIONS



# Fax this sheet to (1) 416 375 4538 or Email PDF to: syed.rizvi@aero.bombardier.com