Revision ‘D’ 10 Apr 2014 DHC ---8 (DASH 8) SERVICE BULLETIN 8 ---24 ---84 Electrical Power --- DC System --- Introduction of New Phoenix GCU Part Number with Undervoltage Protection and Performance Improvements, #1 Engine Generator Channel --- ModSum 8Q101710 This page transmits Revision ‘D’ of Service Bulletin 8 ---24 ---84, pages 1 thru 18 dated 10 Apr 2014 This service bulletin is re ---issued in its entirety for the reasons that follow: --- the Effectivitysection is revised --- added new statement after the Production Effectivity

--- Approval section is revised to add the statement for Airworthiness Limitations (AWLs) and Damage Tolerance Inspections (DTIs)

--- Manpowersection is revised to include a breakdown of the time required and on ---site labor assistance information --- the References section is revised to convey the latest revision of the service bulletin and engineering documentation. --- the Parts Required Per Aircraft section is revised with statement in the Remarks column of the Parts List for label 81151169 --- the Existing Parts Accountabilitysection is revised with additional Existing Part Number --- theACCOMPLISHMENT INSTRUCTIONS section is revised with the changes that follow: --- separated Procedure section into Part 1 and Part 2 --- added ‘or GC ---1010 ---24 ---5II’ to step (1) of Part 1

. The Compliance in the previous issue(s) 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 Revision ‘C’ of this service bulletin are not required to do any further work. No additional rework to the aircraft is introduced by this revision. Remove Service Bulletin 8 ---24 ---84 Revision ‘C’ dated 07 Jul 2009 and replace with attached.Previous issue(s) of Service Bulletin 8 ---24 ---84: Initial issue --- Pages 1 thru 10 dated 22 Aug 2008 Revision ‘A’ --- Pages 1 thru 10 dated 23 Aug 2008 Revision ‘B’ --- Pages 1 thru 10 dated 15 Oct 2008 Revision ‘C’ --- Pages 1 thru 10 dated 07 Jul 2009

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S.B. 8 ---24 ---84 Page 1 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 2461 NUMBER: 8 ---24 ---84
SUBJECT: Electrical Power --- DC System --- Introduction of New Phoenix GCU Part Number with Undervoltage Protection and Performance Improvements, #1 Engine Generator Channel --- ModSum 8Q101710

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 661 with GCU part number GC ---1010 ---24 ---5DIII or GC ---1010 ---24 ---5DII installed. Production: ModSum 8Q101710 has already been installed on applicable DHC ---8 Aircraft at Serial Number 662 and subsequent For Serial Numbers 003 thru 661 with GCU part number 51539 ---008B or 51539 ---008C or 51539 ---008D installed, see Bombardier Service Bulletin 8 ---24 ---89. Spares Affected: None B. Reason Problem: Four occurrences of un ---annunciated failure of the No. 1 DC Starter Generator have been reported since 1995. This caused a low voltage condition of the Left Main DC Bus and prompted emergency descents and landings resulting from the illumination of numerous caution indications of affected systems.

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S.B. 8 ---24 ---84 Page 2 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 Functionality of the FMS and NAV systems were reportedly lost. The transponder systems were also reported to no longer function with the exception of the No. 2 ADF. Given AC Bus and Main/Aux Battery architecture, this failure mode is only applicable to the Left Main DC Bus and #1 Engine generator channel. Solution: This service bulletin conveys ModSum 8Q101710. The modsum installs a new Generator Control Unit (GCU) with undervoltage protection, added filtering to the current transformer inputs to address nuisance trips and additional modifications designed to improve GCU performance. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: --- access is gained to the flight compartment --- the existing #1 Generator Control Unit (GCU) located on the bottom of the co ---pilots circuit breaker console is removed and replaced with a new GCU part number GC ---1010 ---24 ---5DV according to theACCOMPLISHMENT INSTRUCTIONS in this service bulletin and the enclosed vendor service bulletin --- the existing connector label is removed and replaced with a new label --- a new GCU warning label is installed --- an operational test of the DC generator system is done --- close out. D. Compliance Bombardier Inc. recommends incorporation of ModSum 8Q101710 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).

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S.B. 8 ---24 ---84 Page 3 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 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(s) 2.A. may be either furnished or fabricated from the operator’s existing stock, purchased as single items from Bombardier Aerospace Regional Aircraft or purchased directly from industry sources. 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

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S.B. 8 ---24 ---84 Page 4 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 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

............................... L. References Revision ‘D’ of this service bulletin was prepared to the engineering drawings and related data that follows:
DRAWING SHEET REV

8DK4141 1 A
ModSum 8Q101710 Rev. ‘H’ Phoenix Aerospace Inc. Service Bulletin #: 000331 ---1 DATE: AUG 29/08 PCA 05625 Revision 5 (for internal reference only) PCA 05918 Revision NC (for internal reference only) Transport Canada Airworthiness Directive Pending.
2. MATERIAL INFORMA TION A. Parts Required Per Aircraft (1) Detailed Parts List:
Quantity Per Aircraft Part Number Description Remarks

1 81151169 ---101 Warning Label or operator manufactured label 8DK4141 ---101 1 GC ---1010 ---24 ---5DV GCU

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S.B. 8 ---24 ---84 Page 5 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 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.
Existing Part Number Description Qty. IC DC New Part Number PNC 81151169 ---101 N

--- Warning Label 1 N/A N/A or 8DK4141 ---101 N GC ---1010 ---24 ---5DIII or GCU 1 A SAL GC ---1010 ---24 ---5DV N GC ---1010 ---24 ---5DII 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. N/A Not Applicable. 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.

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S.B. 8 ---24 ---84 Page 6 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set ---Up (1) Either pull and clip circuit breakers required to isolate affected circuits or placard and select aircraft electrical power to OFF. Obey all relevant WARNINGS and CAUTIONS detailed in Maintenance Manual PSM 1 ---8 ---2 or PSM 1 ---82 ---2 or PSM 1 ---83 ---2. (2) Refer to Figure 1 and gain access to the flight compartment. Locate the #1 GCU on the bottom shelf of the right DC circuit breaker console. B. Procedure

Part 1 --- GCU Replacement (1) Refer to PSM 1 ---8 ---2 Chapter 24 ---31 ---03 or PSM 1 ---83 ---2 Chapter 24 ---31 ---03 or PSM 1 ---82 ---2 TASK 24 ---31 ---16 ---000 ---801 and Figure 2 and remove existing #1 GCU part number GC ---1010 ---24 ---5DII or GC ---1010 ---24 ---5III from the bottom shelf of the right DC circuit breaker console. (2) Refer to enclosed Phoenix Aerospace Inc. Service Bulletin #: 000331 ---1 and PSM 1 ---8 ---2 Chapter 24 ---31 ---03 or PSM 1 ---83 ---2 Chapter 24 ---31 ---03 or PSM 1 ---82 ---2 TASK 24 ---31 ---16 ---400 ---801 and Figure 2 and install new GCU part number GC ---1010 ---24 ---5DV to bottom shelf of the right DC circuit breaker console. Part 2 --- Label Installation (1) Refer to PSM 1 ---8 ---2 Chapter 20 ---22 ---02 or PSM 1 ---83 ---2 Chapter 20 ---22 ---02 or PSM 1 ---82 ---2 TASK 20 ---22 ---02 ---400 ---801 and Figure 3 and remove and replace existing electrical connector label 2431 ---GCU1 with new warning label 81151169 ---101. (2) If the operator chooses to have the label made locally, do the steps that follow. (a) Refer to Figure 4 and PSM 1 ---8 ---2 Chapter 20 ---22 ---06 or PSM 1 ---83 ---2 Chapter 20 ---22 ---06 or PSM 1 ---82 ---2 TASK 20 ---00 ---11 ---800 ---801 and make the label. (b) Identify label as 8DK4141 ---101. (c) Refer to PSM 1 ---8 ---2 Chapter 20 ---22 ---02 or PSM 1 ---83 ---2 Chapter 20 ---22 ---02 or PSM 1 ---82 ---2 TASK 20 ---22 ---02 ---400 ---801 and Figure 3 and remove and replace existing electrical connector label 2431 ---GCU1 with new warning label 8DK4141 ---101. C. Close Out (1) Remove all tools and equipment from the work area.

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S.B. 8 ---24 ---84 Page 7 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 (2) Refer to PSM 1 ---8 ---2 Chapter 24 ---31 ---00 or PSM 1 ---83 ---2 Chapter 24 ---31 ---00 and do an operational test of the DC Generator System or PSM 1 ---82 ---2 TASK 24 ---31 ---00 ---720 ---801 and do a functional test of the DC Generator System. (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.

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S.B. 8 ---24 ---84 Page 8 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 #1 GCU Location Figure 1 GENERATOR CONTROL UNIT GC ---1010 ---24 ---5DV QTY: 1 LABEL 81151169 ---101 or 8DK4141 ---101 QTY; 1

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S.B. 8 ---24 ---84 Page 9 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 Removal/Installation of Generator Control Unit Figure 2 A

B

B A

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S.B. 8 ---24 ---84 Page 10 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 Label Location Figure 3 WARNING LABEL 81151169 ---101 or 8DK4141 ---101

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S.B. 8 ---24 ---84 Page 11 of 18 22 Aug 2008 MG Revision ‘D’ 10 Apr 2014 Warning Label 8DK4141 ---101 Figure 4 1

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. 1 8DK4141 ---101

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