# Bombardier Service Bulletin 84-33-12

Copy: Revision B ("SB 84-33-12_Rev B"), 12 pages: PDF https://openairdocs.org/files/sha256/66/5b/665bee404520764bba86ad19e1b1730e80234e355b5fb1c3c848c987f82e71ac; text https://openairdocs.org/service-documents/bombardier/sb-84-33-12/file/665bee404520.md. Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2016-9054; AD 2017-06-10 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication.

## Details

- Manufacturer: [Bombardier](https://openairdocs.org/service-documents/bombardier.md)
- Type: Service bulletin (Service Bulletin)
- Number: 84-33-12
- Latest revision known: 84-33-12, Revision B, dated June 28, 2016 (OpenAirDocs)
- Page: https://openairdocs.org/service-documents/bombardier/sb-84-33-12

## ADs that cite it (1) (OpenAirDocs)

Newest first, with the revision each names, as OpenAirDocs read it from the AD's text.

- [AD 2017-06-10](https://openairdocs.org/ad/2017-06-10.md), effective May 1, 2017: Revisions A and B

Also cited in [1 proposed AD](https://openairdocs.org/service-documents/bombardier/sb-84-33-12/proposed.md).

## Text (12 pages)

Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2016-9054; AD 2017-06-10 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

### Page 1

Revision ‘B’ 28 Jun 2016
D H C --- 8 ( D A S H 8 )
S E R V I C E B U L L E T I N 8 4 --- 3 3 --- 1 2
Lights - - - Emergency Lighting - - - Negative Interlock and Ground Wires at the
Emergency Lights Power Supply Changed to 20AWG from 22AWG - - -
Modsum 4- - - 126620
This page transmits Revision ‘B’ of Service Bulletin 84- - -33- - -12, pages 1 thru 8
dated 28 Jun 2016.
This service bulletin is re- - -issued in its entirety for the reasons that follow:
-- the Description section is revised to indicate that individual wires are part
marked
--- t h eReferences section is revised to convey the latest revision of this service
bulletin and related engineering documentation
-- the ACCOMPLISHMENT INSTRUCTIONS section B. Procedure step (9) is
revised to show that part marking of the individual wires to be done using ID
s l e e v e T M S --- S C E 1 / 8 --- 2 . 0 --- 9 o r a n y m e t h o d i n d i c a t e d o n W D M
20- - -10- - -00- - -201.
The Compliance in the previous issue of this service bulletin is not affected by
this revision. No additional rework to the aircraft is introduced by this revision.
Remove the previous Issue of Service Bulletin 84- - -33- - -12 and replace with
attached.
Previous Issue(s) of Service Bulletin 84- - -33- - -12:
Initial Issue - - - Pages 1 thru 8 dated 29 Sep 2015
Revision ‘A’ - - - Pages 1 thru 8 dated 19 Jan 2016

### Page 2

(No text on this page.)

### Page 3

D
S . B . 8 4 --- 3 3 --- 1 2
Page 1 of 8
29 Sep 2015
JR
Revision ‘B’ 28 Jun 2016
SERVICE BULLETIN
Customer
Support
ATA SYSTEM: 3351 NUMBER: 84- - -33- - -12
BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS
SERVICE BULLETIN TO BE PARTICULARL Y SIGNIFICANT AND
URGE OPERATORS TO PROMPTL Y EVALUATE THE CONTENTS
SUBJECT : Lights - - - Emergency Lighting - - - Negative Interlock and Ground Wires at
the Emergency Lights Power Supply Changed to 20AWG from 22AWG
- - - Modsum 4- - - 126620
1. PLANNING INFORMA TION
A. Effectivity
Aircraft Affected:
In- - -Service: DHC- - -8 Aircraft Models 401 and 402 Serial Numbers 4001,
4003 thru 4507.
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

### Page 4

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S . B . 8 4 --- 3 3 --- 1 2
Page 2 of 8
29 Sep 2015
JR
Revision ‘B’ 28 Jun 2016
B. Reason
Problem: The emergency lighting system is tested on a daily basis, prior to each day
of flying, to ensure all lights and exit signs are serviceable.
During this check there have been reports that the emergency lights circuit
breaker was found tripped. Subsequent troubleshooting revealed signs of
thermal stress on the emergency lighting wiring. An investigation has
concluded that the affect of inrush current when testing the system and
ambient temperatures results in the 22AWG wires being loaded to their
current carrying limit. The current passing through the conductor in turn
generates heat in the wires which lead to degration and burning of the
insulation.
Solution: The solution is to change the wires at each of the four Emergency Lights
Power Supplies to 20AWG wires.
C. Description
The procedures in this service bulletin give the instructions to do the tasks that follow:
- - - aircraft electrical power is removed
- - - the nose landing gear lock is engaged
- - - the main landing gear lock pins are installed thru each main gear and main gear door
mechanism
- - - certain ceiling panels are removed
- - - some wires at each emergency power supply is replaced
- - - individual wires are part marked
- - - an operational check of the emergency light system is done
- - - close out.
D. Compliance
Bombardier Inc. highly recommend that ModSum 4- - -126620 be incorporated at the
earliest opportunity unless otherwise directed by the operator’s airworthiness
authority.
Transport Canada Airworthiness Directive CF- - -2016- - -12 Effective Date 11 May 2016.

### Page 5

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S . B . 8 4 --- 3 3 --- 1 2
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29 Sep 2015
JR
Revision ‘B’ 28 Jun 2016
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
# 9 3 --- Q --- 0 2 .
This service bulletin does not affect Airworthiness Limitations (AWLs) or Damage
T olerance Inspections (DTIs).
F. M a n p o w e r
It will take an estimated 8.00 man- - -hours to complete this service bulletin. The
breakdown of the man- - -hours is shown in the table that follows:
TASK M A N --- H O U R S
J o b S e t --- U p 0.25
Procedure 7.00
T e s t/R T S 0.50
Close- - -Out 0.25
This estimate is for direct labour done by an experienced crew and it does not include,
planning, familiarization, cure time, partfabrication, tool acquisition or lost time.
All costs to incorporate this modification are the responsibility of the Operator
G. Material - - - Price and Availability
Drawing Kit(s) (DKs) listed in the table above are drawings only. No parts will be
supplied.
The part(s) and material(s) required are listed in Paragraph 2.A. The parts required
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 illustra tion). 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.

### Page 6

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S . B . 8 4 --- 3 3 --- 1 2
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29 Sep 2015
JR
Revision ‘B’ 28 Jun 2016
If required the related 8DK drawings listed in the T able above can be requested by
writing to the e- - -mail address that follows:
qseriesdwgrequest@aero.bombardier.com
Follow the instructions per All Operator Messages (AOM) 914 (Q100/200/300) or 389
(Q400).
H. T ooling - - - Price and Availability
None
I. Weight and Balance
Not affected
J. Electrical Load Data
Not affected
K. Publications Affected
Wiring Diagrams Manual PSM 1- - -84- - -2W.............................
ModSums Manual PSM 1- - -84- - -12..................................
L. References
Revision ‘B’ of this service bulletin was prepared to the engineering drawings and
related data that follows:
DRAWING SHEET REV
8DK4264 1 B
ModSum 4Q126620 Rev. ‘C’
ModSum 4- - -126620 Rev. ‘C’
PCA 45313 Revision 1 (for internal reference only)
Transport Canada Airworthiness Directive CF- - -2016- - -12 Effective Date 11 May 2016.
ADR: RCLA- - -Q16- - -13351070 (for internal reference only)

### Page 7

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S . B . 8 4 --- 3 3 --- 1 2
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29 Sep 2015
JR
Revision ‘B’ 28 Jun 2016
2. MATERIAL INFORMA TION
A. Parts Required Per Aircraft
(1) Detailed Parts List:
Quantity
Per Aircraft
Part Number Description Remarks
12 T M S --- S C E 1 / 8 --- 2 . 0 --- 9I D Sleeve 3 per cable assembly
4 M7928/4- - -103 Ground Lug 1 per cable assembly
12 M39029/5- - -115 Contact 3 per cable assembly
144 inches 55PC0211- - -20- - -9 20 Gauge Wire 36 inches per cable as-
sembly
B. Parts Required to Modify Spares
None
C. Special T ools and Equipment Required
None
D. Existing Parts Accountability
None
3. ACCOMPLISHMENT INSTRUCTIONS
A . J o b S e t --- U p
WARNING: MAKE SURE YOU 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 ACCIDENTALL Y
RETRACT . THIS CAN CAUSE INJURIES TO PERSONS AND
DAMAGE TO THE EQUIPMENT .

### Page 8

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S . B . 8 4 --- 3 3 --- 1 2
Page 6 of 8
29 Sep 2015
JR
Revision ‘B’ 28 Jun 2016
WARNING: MAKE SURE YOU INSTALL THE LOCKPINS IN THE DOOR
MECHANISMS OF THE MLG AND NLG. THE DOOR MECHANISMS
CAN ACCIDENTALL Y CLOSE THE LANDING GEAR DOORS. THIS
CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE
EQUIPMENT .
NOTE: Make sure to put a protective cover on any disconnected electrical
connector or any tube, hose, duct and/or line.
(1) Placard and select all aircraft electrical power to OFF . Obey all relevant
W A R N I N G S a n d C A U T I O N S ( r e f e r t o A M M T A S K ’ S 2 4 --- 0 0 --- 0 0 --- 8 6 1 --- 8 0 2 a n d
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) Set wheel chocks in front and behind the landing gear tires.
B. Procedure
( 1 ) R e m o v e a p p l i c a b l e c e i l i n g p a n e l s p e r A M M Ta s k 3 3 --- 5 1 --- 0 1 --- 0 0 0 --- 8 0 1 t o g a i n
access to the four emergency power supplies.
(2) At connectors 3351- - -P3/P4/P5 and P6, remove existing 22AWG wiring between
pins 1 and 11.
(3) At connectors 3351- - -P3/P4/P5 and P6, remove existing 22AWG wiring from pin 5
to its associated ground 3351- - -GS11, GS18, GS24 and GS31.
(4) Install 20 AWG wiring per the table below: Refer to Figure 1.

### Page 9

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S . B . 8 4 --- 3 3 --- 1 2
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Revision ‘B’ 28 Jun 2016
(5) At connector 3351- - -P3, part mark wire cable assembly as 8DK4264- - -011 using
I D s l e e v e T M S --- S C E 1 / 8 --- 2 . 0 --- 9 p e r W D M 1 --- 8 4 --- 2 W C h a p t e r 2 0 --- 1 0 --- 0 0 --- 2 0 1
--- W i r e I d e n t i f i c a t i o n --- M a i n t e n a n c e P r a c t i c e s .
(6) At connector 3351- - -P4, part mark wire cable assembly as 8DK4264- - -013 using
I D s l e e v e T M S --- S C E 1 / 8 --- 2 . 0 --- 9 p e r W D M 1 --- 8 4 --- 2 W C h a p t e r 2 0 --- 1 0 --- 0 0 --- 2 0 1
--- W i r e I d e n t i f i c a t i o n --- M a i n t e n a n c e P r a c t i c e s .
(7) At connector 3351- - -P5, part mark wire cable assembly as 8DK4264- - -015 using
I D s l e e v e T M S --- S C E 1 / 8 --- 2 . 0 --- 9 p e r W D M 1 --- 8 4 --- 2 W C h a p t e r 2 0 --- 1 0 --- 0 0 --- 2 0 1
--- W i r e I d e n t i f i c a t i o n --- M a i n t e n a n c e P r a c t i c e s .
(8) At connector 3351- - -P6, part mark wire cable assembly as 8DK4264- - -017 using
I D s l e e v e T M S --- S C E 1 / 8 --- 2 . 0 --- 9 p e r W D M 1 --- 8 4 --- 2 W C h a p t e r 2 0 --- 1 0 --- 0 0 --- 2 0 1
--- W i r e I d e n t i f i c a t i o n --- M a i n t e n a n c e P r a c t i c e s .
(9) Part mark individual wires using ID sleeve TMS- - -SCE 1/8- - -2.0- - -9 or any method
i n d i c a t e d o n W D M 1 --- 8 4 --- 2 W C h a p t e r 2 0 --- 1 0 --- 0 0 --- 2 0 1 --- W i r e I d e n t i f i c a t i o n ---
Maintenance Practices.
C. Close Out
(1) Remove all tools and equipment from the work area.
(2) Install ceiling panels that were removed.
(3) Do an operational check of the emergency light system per AMM T ask
33- - -51- - -00- - -710- - -802 or 33- - -51- - -00- - -710- - -803 or 33- - -51- - -00- - -710- - -804.
(4) 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.

### Page 10 (OCR)

SERVICE BULLETIN 84-33-12
P/0 EFS3
P/0 EPS1  P5  EMERGENCY
EMERGENCY  10  POWER SUPPLY
POWER SUPPLY
-57A-20-2
33A-20-2
11
34A-20N-2-2 G511  GS24 # 58A-20N-2-  LOC CELINC
X654.50
LOC CELING
X010.25
Cable Assembly 8DK4264-011  Cable Assembly 8DK4264-015
P/0 EPS2
EMERGENCY  P/O EPS4
POWER SUPPLY  P4  P6  EMERGENCY
POWER SUPPLY
45A-20-2  - 70A-20-2
11
5  46A-20N-2  QS31 71A-20N-2-
E G518
LOC CELING  LOC CELINC
X083 00  X692. 22
Cable Assembly 8DK4264-013  Cable Assembly 8DK4264-017
Cable Assemblies
Figure 1
29 Sep 2015  S.B. 84-33-12
Revision 'B' 28 Jun 2016  Page 8 of 8
JR

### Page 11

Jan 2009
SERVICE BULLETIN (SB) - - - RECORD OF INCORPORATION
- - - Q SERIES DASH 8 AIRCRAFT
To : CMDB Focal
Facsimile: (1) 416 375 4538
E- -mai l: cmdb.requests@aero.bombardier .com
From:
Company:
Phone: Extn:
Facsimile: Date:
E- -mai l:
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

### Page 12

Feb 2009
SERVICE BULLETIN (SB) - - - COMMENT SHEET - - - Q SERIES DASH 8 AIRCRAFT
To : SB Focal (T oronto), Bombardier Aerospace Commercial Aircraft
Phone: (1) 416 375 4078 Facsimile: (1) 416 375 4538
E- -mai l: syed.rizvi@aero.bombardier .com
From:
Company:
Phone: Extn:
Facsimile: Date:
E- -mai l:
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 T ooling V References V Publications Affected
2. MATERIAL INFORMATION
V Kit Content V Special T ools/Equipment V Parts to Modify Spares
V Consumables V Disposition of Existing Parts V Other
3. ACCOMPLISHMENT INSTRUCTIONS
V J o b S e t --- U p V Procedure V Close- - -Out V Te s t
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

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