Revision ‘C’ 04 Nov 2014 DHC ---8 (DASH 8) SERVICE BULLETIN 8 ---24 ---89 Electrical Power Generation, DC System --- Introduction of DC Generation Control Unit (Goodrich) with Under Voltage Protection to Channel #1 Main Engine --- ModSum 8Q101925 This page transmits Revision ‘C’ of Service Bulletin 8 ---24 ---89, pages 1 thru 10 dated 04 Nov 2014. This service bulletin is re ---issued in its entirety for the reasons that follow:

--- Figure 2 is revised to show the correct part number for the label WAS: 81151169 ---101 NOW: 81151169 ---103 --- the Referencessection is revised to convey the latest revision of the service bulletin and engineering documentation. The Compliance in the previous issues of this service bulletin is not affected by this revision. No additional rework to the aircraft is introduced by this revision. Operators that have incorporated the Initial Issue of this service bulletin are not required to do any further work. No additional rework to the aircraft is introduced by this revision. Remove previous revision of Service Bulletin 8 ---24 ---89 and replace with attached. Previous issues of Service Bulletin 8 ---24 ---89: Initial issue --- Pages 1 thru 10 dated 14 Nov 2011 Revision ’A’ --- Pages 1 thru 10 dated 08 Aug 2012 Revision ’B’ --- Pages 1 thru 10 dated 09 Apr 2014

# D

S.B. 8 ---24 ---89 Page 1 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 2400 NUMBER: 8 ---24 ---89 SUBJECT: Electrical Power Generation, DC System --- Introduction of DC Generation Control Unit (Goodrich) with Under Voltage Protection to Channel #1 Main Engine --- ModSum 8Q101925
1. PLANNING INFORMA TION A. Effectivity Aircraft Affected: In ---Service: DHC ---8 Aircraft Models 102, 103, 106, 201, 202, 301, 311, 314 and 315 Serial Numbers 003 thru 672 with Goodrich GCU Part Number 51539 ---008B or 51539 ---008C or 51539 ---008D installed. 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. Spares Affected: None B. Reason Problem: Since 1995, operators have reported four occurrences of un ---annunciated failure of the No. 1 DC Starter Generator. This has prompted emergency descent and landings resulting from the illumination of numerous caution indications of affected systems. Functionality of the FMS and NAV systems were reportedly lost. The transponder systems were also reported to no longer function with the

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 2 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 exception of the No. 2 ADF. Given DC Bus and Main/Aux Battery architecture, this failure mode is only applicable to the Left Main DC Bus and #1 Engine generator channel. Solution: Install a new DC GCU with under ---voltage protection. 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 Generator Control Unit (GCU) located in the right DC circuit breaker console on the bottom shelf --- the existing GCU is removed and replaced with a new GCU --- the existing connector identification label is removed and replaced with a new label --- close out. D. Compliance Bombardier Inc. recommends incorporation of ModSum 8Q101925 at the earliest opportunity unless otherwise directed by the operator’s airworthiness authority. 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).

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 3 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 F. Manpower It will take an estimated 3.00 man ---hours to complete this service bulletin. The breakdown of the man ---hours is shown in the table that follows: TASK MAN ---HOURS Job Set ---Up 0.50 Procedure 1.00 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 G. Material --- Price and Availability The part(s) and material(s) detailed in Paragraph 2.A. may be either furnished or fabricated from the operator’s existing stock or purchased as single items from Bombardier Aerospace Regional Aircraft. DK parts are to be manufactured and approved locally (refer to disclaimer in the related text or illustration). In some cases, an equivalent to the DK part may be available from Bombardier under the production part number shown as reference in Parts Required Per Aircraft. H. Tooling --- Price and Availability None I. Weight and Balance None J. Electrical Load Data Not affected K. Publications Affected Dash 8 Illustrated Parts Catalogue PSM 1 ---8 ---4 and

.................... PSM 1 ---82 ---4 and PSM 1 ---83 ---4 Modifications Manual PSM 1 ---813 ---12

...............................

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 4 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 L. References Revision ‘C’ of this service bulletin was prepared to the engineering drawings and related data that follows: DRAWING SHEET REV

8DK4177 1 A
ModSum 8Q101925 Rev. ‘G’ PCA 05625 Revision 5 (for internal reference only)
2. MATERIAL INFORMA TION A. Parts Required Per Aircraft (1) Detailed Parts List:
Quantity Per Aircraft Part Number Description Remarks
1 81151169 ---103 Label, GCU Warning Label 1 51539 ---021A GCU 1
B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None D. Existing Parts Accountability The following parts may be affected by this service bulletin. Indented parts are components of the next higher assembly. The quantity (Qty.) column lists the quantity that may be affected per aircraft for non ---indented parts and the quantity per next higher assembly for indented parts.

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 5 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 Existing Part Number Description Qty. IC DC New Part Number PNC

--- Label, GCU 1 N/A DIS 81151169 ---103 N 51539 ---008B or 51539 ---008C GCU 1 1 N/A SAL 51539 ---021A N or 51539 ---008D IC Interchangeability Code A Not interchangeable. B Removed Part. No direct replacement. C Conditionally Interchangeable. Installation of superseded part negates the intent of this service bulletin. N/A Not Applicable. DC Disposition DIS Discard Part. MUI Multiple Usage Item: Return to stock if serviceable. RWK Rework existing part in accordance with this service bulletin. RWI Rework existing part per ..... SAL Salvage. Return to operator’s stores for salvage consideration. PNC Part Number Code N New part. R Part number after rework. S Superseding or equivalent part number. X Reworked part and superseding part are functionally and physically equivalent but not identical.

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 6 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set ---Up

WARNING: YOU MUST INSTALL THE LOCKPINS ON THE MAIN LANDING GEAR. MAKE SURE YOU ENGAGE THE NOSE GEAR LOCK. IF YOU DO NOT DO THIS, THE LANDING GEAR CAN ACCIDENTALLY RETRACT. THIS CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT.

WARNING: YOU MUST INSTALL THE LOCKPINS ON THE LANDING GEAR DOORS. MAKE SURE YOU DISCONNECT THE LANDING GEAR DOORS. IF YOU DO NOT DO THIS THE LANDING GEAR DOORS WILL CLOSE WHEN YOU APPLY THE HYDRAULIC PRESSURE. THIS CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. (1) Refer to PSM 1 ---8 ---2 or PSM 1 ---82 ---2 or PSM 1 ---83 ---2 Chapter 24 and obey all electrical / electronic safety precautions. (2) Refer to PSM 1 ---8 ---2 or PSM 1 ---82 ---2 or PSM 1 ---83 ---2 Chapter 24 and obey all electrostatic discharge safety precautions. (3) Placard and select all aircraft electrical power to OFF. Refer to PSM 1 ---8 ---2 or PSM 1 ---82 ---2 or PSM 1 ---83 ---2 Chapters 12 and 24 and obey the applicable WARNINGS and CAUTIONS. (4) Make sure that lock pins are installed through each main gear and main gear door mechanism. (5) Make sure the nose gear ground lock is engaged. (6) Open and tag the circuit breakers that follow on the left DC circuit breaker panel: (a) DC LOGIC (F9) (b) DC GEN1 EXCITE (G9) (c) L MAIN INPUT (L9) (d) AUX BATT INPUT (M9). (7) Refer to Figure 1 and gain access to the GCU located in the right DC circuit breaker console on the bottom shelf.

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 7 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 B. Procedure (1) Refer to Figure 1 and AMM Chapter 24 ---31 ---03 (100 or 300 series) or AMM TASK 24 ---31 ---16 ---000 ---801 (200 series) and replace the existing #1 GCU with new GCU 51539 ---021A. (2) Refer to Figure 2 and AMM Chapter 20 ---22 ---02 (100 or 300 series) or AMM TASK 20 ---22 ---02 ---400 ---801 (200 series) and remove and replace the existing GCU label with new warning label 81151169 ---103. (3) Refer to Figure 1 and close access to the new GCU. C. Close Out (1) Close the circuit breakers that followon the left DC circuit breaker panel: (a) DC LOGIC (F9) (b) DC GEN1 EXCITE (G9) (c) L MAIN INPUT (L9) (d) AUX BATT INPUT (M9). (2) Remove all tools and equipment from the work area. (3) On incorporation of this ModSum, make an entry that conforms to local regulatory requirements in the applicable logbook(s). Enter component serial numbers if applicable. Enter this ModSum number only after complete and functional incorporation of all work defined in this service bulletin.
THE DESIGN OF THE PART IN THIS DRAWING HAS BEEN APPROVED BY DE HAVILLAND INC. FOR MANUFACTURE BY OR ON BEHALF OF THE RECIPIENT. THE RECIPIENT IS RESPONSIBLE FOR (A) PROPER MANUFACTURE OF THE PART USING THE SPECIFIED MATERIALS AND FOR INCORPORATION OF THE MODIFICATION, ALL IN ACCORDANCE WITH THE DRAWING AND RELATED INSTRUCTIONS, AND (B) APPROVAL OF THE FINAL INSTALLATION BY THE RELEVANT AIRWORTHINESS AUTHORITY. DE HAVILLAND INC. AND BOMBARDIER INC. (BOMBARDIER AEROSPACE REGIONAL AIRCRAFT) DISCLAIM ANY RESPONSIBILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION LOSS OR USE, LOSS OF REVENUE OR LOSS OF PROFIT, ARISING FROM SUCH MANUFACTURE, INCORPORATION AND INSTALLATION.

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 8 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 DC Generator Control Unit --- Removal / Installation Figure 1 A

A B

B

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 9 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 Label Location Figure 2 WARNING LABEL 81151169 ---103 OR 8DK4177 ---101 (MANUFACTURED BY OPERATOR)

### SERVICE BULLETIN 8 ---24 ---89

S.B. 8 ---24 ---89 Page 10 of 10 14 Nov 2011 PM Revision ‘C’ 04 Nov 2014 Warning Label 8DK4177 ---101 Figure 3 8DK4177 ---101

4.50 INCHES1.13 INCHES

1Jan 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