# Bombardier Service Bulletin 84-27-64

Copy: Revision A ("SB 84-27-64 Rev A"), 12 pages: PDF https://openairdocs.org/files/sha256/b1/ca/b1ca7180e7c9cc1988dfbfb8f7239dfcbdbc40650278bbdbba45ad70d958f10b; text https://openairdocs.org/service-documents/bombardier/sb-84-27-64/file/b1ca7180e7c9.md. Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2015-8434; AD 2017-19-27 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: 84-27-64
- Latest revision known: 84-27-64, Revision A, dated July 26, 2016 (OpenAirDocs)
- Page: https://openairdocs.org/service-documents/bombardier/sb-84-27-64

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

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

- [AD 2017-19-27](https://openairdocs.org/ad/2017-19-27.md), effective Nov 1, 2017: Revision A

Also cited in [1 proposed AD](https://openairdocs.org/service-documents/bombardier/sb-84-27-64/proposed.md).

## Text (12 pages)

Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2015-8434; AD 2017-19-27 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. Each page's text from the PDF; open the PDF at a page with #page=N.

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Revision ‘A’ 26 Jul 2016
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D H C --- 8 ( D A S H 8 )
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Flight Controls - - - Spoiler PCU Special Inspection and Rectification
This page transmits Revision ‘A’ of Service Bulletin 84- - -27- - -64, pages 1 thru 8, dated 26
Jul 2016.
This service bulletin is re- - -issued in its entirety for the reasons that follow:
--- s e c t i o n 1 .PLANNING INFORMATION para A. Effectivity is revised to update the
Aircraft Affected section. Was serial numbers 4001 thru 4453, now 4001 thru 4527.
--- s e c t i o n 1 .PLANNING INFORMATION para A. Effectivity is revised to update the
Spares Affected section to include “Parker Service Bulletin 390700- - -27- - -002 section
4 APPENDIX” as additional information
--- s e c t i o n 1 .PLANNING INFORMATION para D. Compliance is revised to include
“Transport Canada has issued Airworthiness Directive CF- - -2015- - -07”
--- s e c t i o n 1 .PLANNING INFORMATION para L. References is revised to convey the
latest revision of the service bulletin, engineering documentation and include
“Transport Canada Airworthiness Directive CF- - -2015- - -07”
--- s e c t i o n 3 .ACCOMPLISHMENT INSTRUCTIONS para A.s t e p( 1 )i sr e v i s e dt o
include “or section 4. APPENDIX in merged VSB 390700- - -27- - -002”
--- s e c t i o n 3 .ACCOMPLISHMENT INSTRUCTIONS para B.s t e p( 1 )i sr e v i s e dt o
include “any of the S/N’s listed in section 4. APPENDIX in merged VSB
390700- - -27- - -002”
The Compliance in the previous issue(s) of this service bulletin is affected by this
revision. Addition serial numbers of Spoiler PCU’s have been introduced in the latest
issue of merged Parker Service Bulletin 390700- - -27- - -002.
All operators are advised to check again all affected aircraft for the additional serial
numbers introduced in Parker Service Bulletin 390700- - -27- - -002 section 4. APPENDIX. to
determine if any existing Spoiler PCU’s are in range. If so, corrective action needs to be
accomplished.
Remove the initial issue of Service Bulletin 8 4- - -27- - -64 (which includes the merged VSB),
and replace with attached.

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Previous issue(s) of Service Bulletin 84- - -27- - -64:
Initial issue - - - Pages 1 thru 6 dated 15 Jul 2014
1

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SERVICE BULLETIN
Customer
Support
ATA SYSTEM: 2700 NUMBER: 84- - -27- - -64
BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS
SERVICE BULLETIN TO BE PARTICULARL Y SIGNIFICANT AND
URGE OPERATORS TO PROMPTL Y EVALUATE THE CONTENTS
SUBJECT : Flight Controls - - - Spoiler PCU Special Inspection and Rectification
1. PLANNING INFORMA TION
A. Effectivity
Aircraft Affected:
In- - -Service: DHC- - -8 Aircraft Models 401 and 402 Serial Numbers 4001
thru 4527.
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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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.
Part Number Description
P/N’s 390700- - -1007 and 1009 with S/N 0474 through
1321, any of the S/N’s listed in merged Parker Service
Bulletin 390700- - -27- - -002 section 4. APPENDIX, or S/N’s
1394 through 1876, without suffix ‘A’
Spoiler PCU
NOTE: Spoiler PCU’s previously reworked by Parker, as denoted by suffix “ A ”
after the S/N, are already compliant with this Service Bulletin.
B. Reason
Problem: During endurance testing, Parker h as identified the potential for axial crack
starting to develop along the PCU manifold cylinder bore, at the
intersection of a 0.281 inch diameter port. No cracks have been reported
in service. The condition has been attributed to a range of PCU manifolds
produced under a specific heat treat process. It can limit the service life of
the manifold sub- - -assembly P/N 390752 to 56,000 flight cycles. Parker has
developed a rework procedure, when incorporated, will remove the life
limitation.
C. Description
The procedures in this service bulletin give the instructions to do the tasks that
follow:
- - - maintenance records are checked for the spoiler PCU serial numbers
- - - 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

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LSRevision ‘A’ 26 Jul 2016
- - - inboard and outboard spoiler power control units (PCU) are inspected for a specific
serial number
- - - If the specific serial number is on the PCU, the unit is removed and returned to
Parker for rework
- - - If none of the PCU’s have the specific serial numbers no further work is required
- - - an operational test of the roll spoiler system is done if any of the units are changed
- - - close out.
D. Compliance
Bombardier Inc. recommends that the special inspection and rectification on this
service bulletin be done at the earliest opportunity but no later than 56,000 flight
cycles, unless otherwise directed by the operator’s airworthiness authority.
Transport Canada has issued Airworthiness Directive CF- - -2015- - -07.
E. Approval
The technical content of this service bulletin has been approved under the
authority of the Transport Canada Civil Aviation (TCCA) Design Approval
O r g a n i z a t i o n N o : D A O # 9 3 --- Q --- 0 2 .
This service bulletin does not affect Airworthiness Limitations (AWLs) or Damage
T olerance Inspections (DTIs).

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F. M a n p o w e r
It will take an estimated 2.5 man- - -hours to remove and install each affected unit.
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 1.00
T e s t/R T S 1.00
Close- - -Out 0.25
For any on- - -site labor assistance, please contact a Fleet Services representative for a
quote. The Fleet Services group can be contacted via the Q Series T echnical Help
Desk by telephone at 416- - -375- - -4000 or email at: thd.qseries@aero.bombardier.com
G. Material - - - Price and Availability
Refer to Parker Service Bulletin 390700- - -27- - -002.
H. T ooling - - - 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- - -84- - -4....................

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L. References
Revision ‘A’ of this service bulletin was prepared to the engineering drawings and
related data that follows:
PCA 44794 Revision 2 (for internal reference only)
Transport Canada Airworthiness Directive CF- - -2015- - -07.
2. MATERIAL INFORMA TION
NOTE: Parker automatically incorporates this Service Bulletin if a spoiler PCU in
the affected S/N range is returned for repair or upgrade for reasons such
as SB 84- - -27- - -63. If a unit is repaired or upgraded by a non Parker
facility, check its S/N for effectivity with this Service Bulletin.
A. Parts Required Per Aircraft
Refer to Parker Service Bulletin 390700- - -27- - -002.
B. Parts Required to Modify Spares
Refer to Parker Service Bulletin 390700- - -27- - -002.
C. Special T ools and Equipment Required
None
D. Existing Parts Accountability
None

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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 .
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 .
(1) Inspect all maintenance records to determine the spoiler PCU S/N installed in
the aircraft. If each unit’s S/N is outside the affected range as indicated in
section 1.A. of this Service Bulletin or section 4. APPENDIX in merged VSB
390700- - -27- - -002 or if the S/N has suffix “ A ”, no further action is required; go to
section 3.C. Close Out.
(2) 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).
(3) Make sure that lock pins are installed through each main gear and main gear
door mechanism.
(4) Make sure the nose gear ground lock is engaged.
(5) Set up the work platforms or ladders as required to gain access to the inboard
and outboard spoiler power control units (PCU). Make sure the work platforms
or ladders are electrically grounded.

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B. Procedure
(1) Inspect inboard and outboard spoiler power control units/actuators (PCU) P/N’s
390700- - -1007 and - - -1009 and see if they are within the range of S/N 0474
through 1321, any of the S/N’s listed in section 4. APPENDIX in merged VSB
390700- - -27- - -002, or S/N 1394 through 1876, without suffix “ A ”.
(2) If any of the four PCU’s contain any of the serial numbers specified do as
follows:
(a) Remove affected unit per AMM T ask 27- - -61- - -21- - -000- - -801 or
27- - -61- - -16- - -000- - -801.
(b) Return affected unit to Parker per Parker Service Bulletin 390700- - -27- - -002.
(c) Install reworked PCU or PCU outside the affected range per AMM T ask
27- - -61- - -21- - -400- - -801 or 27- - -61- - -16- - -400- - -801.
(d) Do an operational test of the roll spoilers system per AMM T ask
27- - -61- - -00- - -710- - -801.
(3) If none of the PCU’s contain the specified serial numbers, no further work is
required.
C. Close Out
(1) Remove all tools and equipment from the work area.
(2) Close any access panels that were removed.
(3) On completion of this service bulletin, make the following entry in the
appropriate logbooks: “Service Bulletin 84- - -27- - -64 Flight Controls - - - Spoiler
PCU Special Inspection and Rectification accomplished.”

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1

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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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