Tx Ltr SB 84-52-77

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Revision ‘C’ 05 Jun 2014

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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 documentation, 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

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SERVICE BULLETIN 84-52-77

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Revision ‘C’ 05 Jun 2014

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S.B. 84-52-77

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31 Aug 2012

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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.

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SERVICE BULLETIN 84-52-77

S.B. 84-52-77

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31 Aug 2012

Revision ‘C’ 05 Jun 2014

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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 installed 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.

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SERVICE BULLETIN 84-52-77

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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 Assembly:

- a replacement airstair step assembly is installed on the airstair door assembly.

- the airstair door assembly is installed on 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.

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SERVICE BULLETIN 84-52-77

S.B. 84-52-77

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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

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SERVICE BULLETIN 84-52-77

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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)

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SERVICE BULLETIN 84-52-77

S.B. 84-52-77

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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.

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SERVICE BULLETIN 84-52-77

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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”.

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SERVICE BULLETIN 84-52-77

S.B. 84-52-77

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31 Aug 2012

Revision ‘C’ 05 Jun 2014

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Inspection Through the End Panel Assembly - FWD Passenger Door

Figure 1 (Sheet 1)

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SERVICE BULLETIN 84-52-77

S.B. 84-52-77

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31 Aug 2012

Revision ‘C’ 05 Jun 2014

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Inspection Through the End Panel Assembly - FWD Passenger Door

Figure 1 (Sheet 2)

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SERVICE BULLETIN 84-52-77

S.B. 84-52-77

Page 10 of 10

31 Aug 2012

Revision ‘C’ 05 Jun 2014

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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. 

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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 | 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. 

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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 | 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 

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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 | 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-contained (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 Bulletin. 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 

 

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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 | 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. 

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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 | 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 Door 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. 

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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 | 8 

Remove light assemblies as required to inspect for 

the serial number at View A, B or C 

Location of the Serial Number – Example A on Aft Sidewall 

Picture 1 

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Basic

Revis

Revis

Revis

c – July 25, 2

sion A - Dece

sion B - Octo

sion C - Febr

SERVI

2012 

ember 12, 20

ober 22, 2013

ruary 26, 201

ICE BU

 

012 

3

14 

Stai

Step Ass

ULLETI

 

ir Tread of S

sembly – Me

Pictur

IN D84

tep Assembl

ethod of Insp

re 2 

00-52-0

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ly 

ection 

0011

8400-52-001

Page |

1

9 

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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 inspection of the Dash8/400 airstair door. This 

procedure consists of performing an electronic 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 made of glass fiber and fibrous Nylon 

honeycomb core 

C. The airstair door steps are assembled with the walls by mortise and tenon 

joint. 

D. The tenons may have been installed with or without epoxy compound. 

NOTE: If the tenons were installed 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 tenons have been installed 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 follows was used in the development of this procedure 

1) Portable electronic tap tester Mitsui Woodpecker WP-632AM made by 

Cadex Japan. Refer to Figure 2 sheet 1 

NOTE: WP-632 electronic tap tester Mitsui Woodpecker with WP-632M 

 (external monitoring unit) made by Cadex 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 

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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 must be familiar with the structure being 

inspected and the use of the electronic tap tester. Personnel must read 

the general information on electronic tap 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 the inspection area is clean and dry 

B. Use the marker pen and mark the location 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 the 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 button to select the insert mode 

3) Press the AVE_SET button to set the average (AVE) number of 

taps to 2 and the tap frequency to 8 taps/sec 

4) Put the hammer feet on the CTS over the defect. Refer to Figure 2 

5) Press and hold the blue memory switch while you move the 

instrument slightly on the surface of the CTS to acquire the 

standard reference value. The value will be between 38 and 41 

6) Once the standard reference value 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 moved away from the defect 

 the buzzer will come on 

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Bombardier Appendix A

SB 84-52-77

3

 the combination LED that shows 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 the inspection area at the location 

shown just outside the step trace (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 /Stop Button to start scanning 

G. Do a scan toward the mortise/tenon joint shown in Detail A only 

1) If the location tapped alarms the buzzer 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 with epoxy compound. The steps are 

only sealed at the joint 

10. INDICATION EVALUATION

A. If the insert (tenon) cannot be detected 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 Brothers Service Bulletin D8400-52-

0011. 

12. REPORTING

 N/A 

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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 

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Bombardier Appendix A

SB 84-52-77

5

NOTE: Drawing not to scale 

Figure 1 Sheet 2 

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Bombardier Appendix A

SB 84-52-77

6

Equipment Figure 2 sheet 1 

INSERT 

WP- 632AM 

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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 2 

Bombardier PDF Merged Document SB 84-52-77C_05 Jun 2014 & Shorts VSB D8400-52-0011Revision C_February 26, 2014 Page 29 of 29
Jan 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.com
Feb 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