# D

S.B. 84 ---27 ---63 Page 1 of 8 17 Oct 2013 MG 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 2700 NUMBER: 84 ---27 ---63
SUBJECT: Flight Controls --- Outer Wing --- Spoiler PCU --- Design Change to Eliminate Inadvertent Deployment --- ModSum 4 ---113783

1. PLANNING INFORMA TION A. Effectivity Aircraft Affected: In ---Service: DHC ---8 Aircraft Models 401 and 402 Serial Numbers 4001, 4003 thru 4453. Production: ModSum 4 ---113783 will be installed before delivery on applicable DHC ---8 Aircraft at Serial Number 4454 and subsequent. 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: Operators have reported numerous cases of inadvertent deployment of a single outboard spoiler in ---flight. In all cases the inadvertent deployment occurred when airspeed decreased below 165 kts and outboard spoilers became enabled. The lift dump valve upgrade thru Bombardier Service Bulletin 84 ---27 ---43 (mandated by TC AD CF ---2009 ---26) has not reduced the rate of occurrence in the fleet. The controllability of the aircraft could be significantly affected if an inadvertent deployment of a spoiler occurred in combination with an engine failure or jam in the aileron system.

### SERVICE BULLETIN 84 ---27 ---63

S.B. 84 ---27 ---63 Page 2 of 8 17 Oct 2013 MG Cause: Investigation has identified the root cause as seal blow ---by at the spoiler PCU main control valve, causing a leak path from the supply pressure to the PCU extend chamber. Solution: Remove and replace the existing outboard spoiler PCU’s with revised PCU’s designed with seal blow ---by 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 thru each main gear and main gear door mechanism --- access is gained to the outboard spoiler PCU’s ---left and right hand side --- the PCU’s are removed and replaced with revised PCU’s reworked by Parker per Parker VSB 390700 ---27 ---001 --- an operational test of the roll spoiler system is done --- close out.

NOTE:This service bulletin is applicable to the outboard spoiler PCU’s only. It does not authorize upgrade of the inboard spoiler PCU’s, as it will be addressed per Bombardier Service Bulletin 84 ---27 ---62.
D. Compliance Bombardier Inc. recommends incorporation of ModSum 4 ---113783 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 84 ---27 ---63

S.B. 84 ---27 ---63 Page 3 of 8 17 Oct 2013 MG F. Manpower It will take an estimated 4.50 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 (left and right hand side) 2.00 Test / RTS 1.50 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 parts detailed in Paragraph 2.A. may be either purchased as single items from Bombardier Aerospace Regional Aircraft or purchased directly from industry sources. 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 ---84 ---4

.................... ModSums Manual PSM 1 ---84 ---12

.................................. L. References The initial issue of this service bulletinwas prepared to the engineering drawings and related data that follows:

### SERVICE BULLETIN 84 ---27 ---63

S.B. 84 ---27 ---63 Page 4 of 8 17 Oct 2013 MG DRAWING SHEET REV

8DK4220 1

--- ModSum 4Q113783 Rev. ‘C’ ModSum 4 ---113783 Rev. ‘D’ PCA 43563 Revision 1 (for internal reference only) 2. MATERIAL INFORMA TION A. Parts Required Per Aircraft (1) Drawing Kit 8DK4220 ---001, Retrofit --- Flight Spoiler PCU/Actuator, RH/LH Outboard (2) Detailed Parts List: Quantity Per Aircraft Part Number Description Remarks

2 390700 ---1009 Actuator 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 390700 ---1007 Actuator 2 C RWK 390700 ---1009 R IC Interchangeability Code A Discarded part. B Reworked Part. No direct replacement. C Conditionally Interchangeable. Installation of superseded part negates the intent of this service bulletin.

### SERVICE BULLETIN 84 ---27 ---63

S.B. 84 ---27 ---63 Page 5 of 8 17 Oct 2013 MG 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 number 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. 3. ACCOMPLISHMENTINSTRUCTIONS A. Job Set ---Up

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 ACCIDENTALLY 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 ACCIDENTALLY CLOSE THE LANDING GEAR DOORS. THIS CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. (1) Placard and select all aircraft electrical power to OFF. Obey all relevant WARNINGS and CAUTIONS (refer to AMM TASK’S 24 ---00 ---00 ---861 ---802 and 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.

### SERVICE BULLETIN 84 ---27 ---63

S.B. 84 ---27 ---63 Page 6 of 8 17 Oct 2013 MG (4) Set up the work platforms or ladders as required to gain access to the PCU’s for the outboard flight spoilers ---left and right hand side. Make sure the work platforms or ladders are electrically grounded (refer to Figure 1). (5) Open and tag the circuit breakers that follow: CB PANEL AND CB NO NAME LEFT DC (ESSENTIAL), F8 HYD PRESS IND 1 LEFT DC (ESSENTIAL), H7 HYD SYS CONT RIGHT DC (ESSENTIAL), F6 ROLL SPLRS ---ARM ---OUTBD RIGHT DC (ESSENTIAL), H6 ROLL SPLRS ---ARM ---IND RIGHT DC (ESSENTIAL), L8 HYD PWR XFER RIGHT DC (ESSENTIAL), M8 HYD PRESS IND 2 RIGHT DC (ESSENTIAL), M7 HYD SYS 3 CONT (6) Remove the access panels that follow: REFERENCE DESIGNATION 532ST Panel 542AL Panel 642AL Panel 632EB Closure Panel
B. Procedure (1) Refer to AMM TASK 27 ---61 ---16 ---000 ---801 and remove two existing PCU’s 390700 ---1007 used for the outboard flight spoilers ---left and right hand side. Removed PCU’s may be returned to Parker for upgrade to 390700 ---1009 (reference Parker VSB 390700 ---27 ---001). (2) Refer to AMM TASK 27 ---61 ---16 ---400 ---801 and install two PCU’s 390700 ---1009 for the outboard flight spoilers ---left and right hand side.
C. Close Out (1) Remove the tags and close the circuit breakers that follow:

### SERVICE BULLETIN 84 ---27 ---63

S.B. 84 ---27 ---63 Page 7 of 8 17 Oct 2013 MG CB PANEL AND CB NO NAME LEFT DC (ESSENTIAL), F8 HYD PRESS IND 1 LEFT DC (ESSENTIAL), H7 HYD SYS CONT RIGHT DC (ESSENTIAL), F6 ROLL SPLRS ---ARM ---OUTBD RIGHT DC (ESSENTIAL), H6 ROLL SPLRS ---ARM ---IND RIGHT DC (ESSENTIAL), L8 HYD PWR XFER RIGHT DC (ESSENTIAL), M8 HYD PRESS IND 2 RIGHT DC (ESSENTIAL), M7 HYD SYS 3 CONT (2) Refer to AMM TASK 27 ---61 ---00 ---710 ---801 and do an operational test of the roll spoiler system. During the operational test, make sure that there is clearance between the spoiler components and the aircraft structure or other components. (3) Install the access panels that follow: REFERENCE DESIGNATION 532ST Panel 542AL Panel 642AL Panel 632EB Closure Panel (4) Remove all tools and equipment from the work area. (5) 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.

### SERVICE BULLETIN 84 ---27 ---63

S.B. 84 ---27 ---63 Page 8 of 8 17 Oct 2013 MG Flight Spoiler PCU / Actuator --- Left Hand and Right Hand Side --- Outboard Figure 1 LOCATION OF RETROFIT

1