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 INFORMATION

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 bulletin was 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 INFORMATION

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. ACCOMPLISHMENT INSTRUCTIONS

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