Revision ‘A’ 22 Feb 2013 DHC-8 (DASH 8) SERVICE BULLETIN 8-33-56 Lights - Exterior, Taxi Lights - Introduction of Nose Gear Downlock (NGDLK) Permissive Taxi Light Circuit to Eliminate Possibility of False Indication (NG ALT DLK IND) - ModSum 8Q101968
NOTE: The initial issue of this service bulletin is not posted on RACS and was issued to one customer for “release to service” of verification aircraft serial number 342. This page transmits Revision ‘A’ of Service Bulletin 8-33-56, pages 1 thru 10 dated 22 Feb 2013. This service bulletin is re-issued in its entirety for the reasons that follow: - the In-Service part of the Effectivity section is revised to include all DHC-8 aircraft s/n’s (003 thru 672). Was limited to only s/n 342 - the Reason section is revised to make an editorial change. Was “EDI”, now “EDIS” - the Referencessection is revised to convey the latest revision of this service bulletin. - theJob Set-Upsection is revised to make editorial changes that follow in two steps. Was “sht”, now “sheet” - theProceduresection is revised to make a few editorial changes that follow in various steps: Was “sht”, now “sheet” Was “Connect / terminate”, now “Connect and/or terminate” Was “a” now “an” Was “turn”, now “rotate” step (3) is deleted step (6) is revised to provide details on how to do a continuity check and provide a maximum resistance limitThe 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. Remove the initial issue of Service Bulletin 8-33-56 and replace with attached. Previous issue(s) of Service Bulletin 8-33-56 Initial issue - Pages 1 thru 8 dated 11 Feb 2013

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S.B. 8-33-56 Page 1 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 3341 NUMBER: 8-33-56 

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

SUBJECT: Lights - Exterior, Taxi Lights- Introduction of Nose Gear Downlock (NGDLK) Permissive Taxi Light Circuit to Eliminate Possibility of False Indication (NG ALT DLK IND) - ModSum 8Q101968

1. PLANNING INFORMATION 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 Mod 8/1519 incorporated. Verification: ModSum 8Q101968 has been installed on DHC-8 Aircraft Model 311 Serial Number 342. 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

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 2 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 B. Reason Problem: One operator has recently experienced an incident and reported that the emergency downlock indication system (EDIS) had given false “down and locked” indication. Cause: Analysis of the EDIS indicates that a false indiction, regardless of the condition of the landing gear, can be caused by a failure of the photo transistors or wiring, or the presence of alternate light source. Solution: This service bulletin introduces ModSum 8Q101968. It introduces wiring modification to inhibit the illumination of taxi light when nose landing gear is in transition or retracted. An intermediate relay circuit is introduced to be put in between the taxi light switch and the taxi light relay wiring. A new connection to the advisory light system and PSEU is introduced. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: - the aircraft electrical system is de-energized - lock pins are installed through each main gear and main gear door mechanism - the nose gear ground lock is engaged - the terminal connector from the Main andAuxiliary batteries are disconnected - panels are removed from the wardrobe to gain access to relay panel No.1, No.2 and No.3 as applicable - relay panels are released (as required) to provide access to the wiring and relay base plates - access is gained to the under floor cross over disconnect - relay p/n X-D4N is installed and label p/n CSP255-3344-K2 is applied to relay panel No.1 or No.3 as applicable - cable assembly 8Z0377-011 is installed and terminated - a continuity check is accomplished to verify compliance with the electrical schematic view - the battery terminal connector is re-connected to the Main and Auxiliary battery

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 3 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 - a taxi light NGDLK functional test procedure is completed - all remove access panels and floor panels are re-installed and closed - close out. D. Compliance Bombardier Inc. highly recommend that ModSum 8Q101968 be incorporated at the earliest opportunity unless otherwise directed by the operator’s airworthiness authority. A Transport Canada Airworthiness Directive is Pending. 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 It will take an estimated 8 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 1.00 Procedure 5.50 Test / RTS 0.50 Close-Out 1.00 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

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 4 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 G. Material - Price and Availability The parts necessary to do this service bulletin are available through the Customer Accounts Service Team at Bombardier Aerospace Regional Aircraft division. Operators should submit a purchase order specifying aircraft serial number(s) to: Bombardier Aerospace Customer Accounts Services Team (Mail Stop N11-32) 123 Garratt Blvd. Toronto Ontario Canada M3K-1Y5 Facsimile: (416) 375-3060 Telephone: (416) 375-3920
Kit Number Description 8MK4645-001 Kit - Taxi Light Redesign to Eliminate Possibility of False Indication

H. Tooling - Price and Availability None I. Weight and Balance None
J. Electrical Load Data 1. Direct Current (DC) Load Change

Item Equipment Bus Bus Code Load Operating Condition 33Q7 Relay Taxi Light 28 V DC Left Main Bus G1 +0.06 Amps Taxi

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 5 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 2. Alternating Current (AC) Load Change
Item Equipment Bus Bus Code Phase VA PF Load Operating Conditions N/A N/A N/A N/A N/A N/A N/A N/A N/A K. Publications Affected Aircraft Operating Data Manual PSM 1-81-1 and

....................... PSM 1-82-1 and PSM 1-83-1 Flight Manual PSM 1-81-1A and

...................................... PSM 1-82-1A and PSM 1-83-1A PSM 1-82-1B and PSM 1-83-1B Maintenance Manual PSM 1-8-2 and

................................ PSM 1-82-2 and PSM 1-83-2 Wiring Diagrams Manual PSM 1-8-2W and

............................ PSM 1-82-2W and PSM 1-83-2W 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 ‘A’ of this service bulletin was prepared to the engineering drawings and related data that follows: DRAWING SHEET REV 8MK4645 1

--

8Z0377 1 A 8Z0377 2 A 8Z0377 3 A

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 6 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 ModSum 8Q101968 Rev. ‘B’ PCA 06824 Revision 1 (for internal reference only) Bombardier Inc. Modification 8/1519 (Service Bulletin 8-33-28 revision ‘A’). Transport Canada Airworthiness Directive is Pending. 2. MATERIAL INFORMATION A. Parts Required Per Aircraft (1) Modification Kit 8MK4645-001 (2) Detailed Kit Content:

Quantity Per Kit -001 Part Number Description Remarks

100 MS3367-1-9 Tie Wrap Quantity may besurplus to account for losses 1 CSP255-3344-K2 Label 1 X-D4N Relay 1 8Z0377-011 Cable Assembly For A/C Post Mod 8/1519 Ref 8Z0377 Drawing -Taxi LT Wiring Drawing only
B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 7 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 D. Existing Parts Accountability None 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set-Up (1) Placard and select all aircraft electrical power to OFF. Obey all relevant WARNINGS and CAUTIONS detailed in Maintenance Manual PSM 1-8-2, 1-82-2 or 1-83-2 Chapters 12 and 24. (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) Disconnect the terminal connectorfrom the Main and Auxiliary battery. (5) For Dash 8 Series 100 and 200, remove panels from the wardrobe to gain access to relay panels No. 1 and 2 (refer to drawing 8Z0377 sheet 3 for location). (6) For Dash 8 Series 300, remove panels from the wardrobe to gain access to relay panels No. 2 and 3 (refer to drawing 8Z0377 sheet 3 for location). (7) Remove bulkhead assembly wing 82523363 (the panel located outboard of the forward PA handset) for access to relay panel 3 and PSEU rear tray. (8) Remove and keep fasteners securing relay panel No. 1. Pull panel out far enough to gain access to the wiring and relay base plates. Support and hang the relay panel temporarily with tie wraps or equivalent. B. Procedure (1) Install relay p/n X-D4N to relay panel using supplied fasteners (refer to applicable view of relay panel given on drawing 8Z0377 sheet 3). (2) Apply label CSP255-3344-K2 to panel next to new relay. Make sure to wipe clean the affected area on the relay panel before applying label. (3) Deleted.

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 8 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 (4) Install and/or terminate cable assembly 8Z0377-011 to agree with all of the NOTES and the detail views given on drawing 8Z0377 sheet’s 2 and 3. (a) Make sure to assemble the ident sleeves DSC347-1/2-2.00-9 & DSC347-1/4-2.00-9, splices M81824/1-2, contact sockets 002-3261-000, pins, relay, relay base and all other related hardware called up on the drawing to new cable assembly as required. (b) For crimping of electrical contacts refer to AMM Chapter 20-45-09 for 100 and 300 series aircraft or AMM TASK 20-45-09-02 for 200 series aircraft. (c) For electrical bonding, refer to AMM Chapter 51-80-00 for 100 and 300 series aircraft or AMM TASK 51-80-00-02 for 200 series aircraft. (d) For splicing , refer to AMM Chapter 20-45-07 for 100 and 300 series aircraft or AMM TASK 20-45-07-02 for 200 series aircraft. (e) For identification of wires and components, refer to AMM Chapter 20-45-13 for 100 and 300 series aircraft or AMM TASK 20-45-13-02 for 200 series aircraft. (5) Secure new cable assembly 8Z0377-011 to existing cable assemblies using tie wraps MS3367-1-9 where additional support is required. (6) Do a continuity check of the new and the existing wires shown on drawing 8Z0377 sheet 2 as follows: (a) Connect the negative (-) lead of an ohmmeter to one end of a wire to be tested and the positive lead (+) of an ohmmeter to the opposite end of the same wire. (b) For long distance checking of a wire connect one end of a wire to be tested to the positive lead (+) of an ohmmeter and the other end of the wire to a ground point with a jumper wire. Connect the negative lead (-) of an ohmmeter to the same ground point. (c) A complete circuit (or closed circuit) from point to point must exist through each wire. The maximum resistance permitted between the two points in a closed circuit is 5 ohms. NOTE: Continuity of a circuit is affected when a diode is part of a circuit. When checking continuity across a diode the electrical polarity must be observed. Continuity of a circuit is also affected when a circuit contains computer controllers, valves, relays, coils, circuit breakers, etc. Temporarily disconnect or remove all the electrical components connected to the wires to be tested. Reconnect components after testing. (d) If the resistance exceeds 5 ohms from point to point (open circuit) recheck the

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 9 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 new and reworked wiring to make sure it is terminated to the correct connection, check the wiring for mechanical damage, loose connector parts, bent pins and corrosion. Correct the deficiency. (7) Connect the battery terminal connectorto the Main and Auxiliary battery. Make sure to safety the battery terminal connector with copper lockwire. CAUTION: DO NOT APPLY HYDRAULIC POWER DURING THE FUNCTIONAL TEST. (8) Do the TAXI LIGHT INTERLOCK functional test procedure given on drawing 8Z0377 sheet 1. C. Close Out (1) Remove all tools, equipment and unwanted materials from the work area. (2) Close all access panels that were previously removed to do this ModSum. (3) On incorporation of this ModSum make an entry that conforms to local regulatory requirements in the applicable logbook(s). If only part of this ModSum is completed, use only this service bulletin number as reference and detail exact limit of work completed. Enter component serial numbers if applicable. Enter this ModSum number only after complete and functional incorporation of all work defined in this service bulletin.

### SERVICE BULLETIN 8-33-56

S.B. 8-33-56 Page 10 of 10 11 Feb 2013 LS Revision ‘A’ 22 Feb 2013 

### This Page Intentionally Blank 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 VApproval 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