Revision ‘A’ 22 Mar 2011 DHC ---8 (DASH 8) SERVICE BULLETIN 84 ---27 ---21 Flight Controls --- Rudder and Brake Control --- Replacement of Rudder Control and Brake Control Pushrod Assemblies to Substitute T4 Pushrod with T6 --- ModSum 4 ---113455 This page transmits Revision ‘A’ of Service Bulletin 8 ---27 ---21, pages 1 thru 10 dated 22 Mar 2011. This service bulletin is re ---issued for the reasons that follow: The requirement to do a “straightness inspection” of existing brake rudder control pushrods p/n 82710274 ---001 per the initial issue of this service bulletin is no longer applicable and has been deleted. The existing brake rudder control pushrods p/n 82710274 ---001 are simply replaced with new pushrods p/n 82710274 ---951. --- the Description part of the PLANNING INFORMATION section and the Procedure part of the ACCOMPLISHMENT INSTRUCTIONS are revised accordingly per above para --- theCompliancesection is revised to include the following: “A Transport Canada Airworthiness Directive is pending” --- the Referencessection is revised to convey the latest revision of this service bulletin Compliance: Aircraft that are in compliance with the initial issue of this service bulletin and have installed brake rudder pushrods p/n 82710274 ---951 are unaffected by this revision. Aircraft without brake rudder pushrods p/n 82710274 ---951 are affected. Rework is required. Bombardier Aerospace highly recommends replacement of all affected pushrods p/n 82710274 ---001 with pushrods p/n 82710274 ---951 at the operators earliest opportunity. Remove the initial issue of Service Bulletin 84 ---27 ---21 and replace with attached. Previous issue(s) of Service Bulletin 84 ---27 ---21: Initial issue --- Pages 1 thru 10 dated 10 Oct 2008

# D

S.B. 84 ---27 ---21 Page 1 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 2720 NUMBER: 84 ---27 ---21 

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

SUBJECT: Flight Controls --- Rudder and Brake Control --- Replacement of Rudder Control and Brake Control Pushrod Assemblies to Substitute T4 Pushrod with T6 --- ModSum 4 ---113455

1. PLANNING INFORMA TION A. Effectivity Aircraft Affected: In ---Service: DHC ---8 Aircraft Models 401 and 402 Serial Numbers 4001, 4003 thru 4006, 4008 thru 4072.
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: The following is a list of spares affected by this change. Review spares and procurement systems to determine the existence of any listed parts. See Paragraph 2.D., Existing Parts Accountability, for disposition.

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 2 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 Part Number Description Remarks 82710274 ---001 Pushrod --- Brake, Rudder Pedal Manufactured after April 1998 82710028 ---003 Pushrod --- Rudder Control Manufactured after February 1997 B. Reason Problem: Some pushrods may have been incorrectly manufactured with tubes having the wrong heat treat condition using 6061 ---T4 instead of 6061 ---T6. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: --- four rudder control pushrods and two brake control pushrods are replaced --- removed pushrods are destroyed and discarded --- new brake and rudder control pushrods are installed and rigged --- a functional test of the brake control system and rudder control system is performed --- close ---out D. Compliance Bombardier Aerospace highly recommends that this modification be incorporated at the operators earliest opportunity, unless otherwise directed by their 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.

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 3 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 F. Manpower It will take an estimated 10 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 0.00 Procedure 9.00 Test / RTS 1.00 Close ---Out 0.00 G. Material --- Price and Availability ModKit 8MK4277 ---001 is 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 Price (US$) Delivery 8MK4277 ---001 Retrofit Kit ---Control Rod Assembly Replacement --- Rudder Control Quoted at time of order Will be given at time of order

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 4 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 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 Revision ‘A’ of this service bulletin was prepared to the engineering drawings and related data that follows: DRAWING SHEET REV 8MK4277 1

--- --- ModSum 4Q113455 Rev. ‘B’ ModSum 4 ---113455 Rev. ‘B’ PCA 40535 Revision --- --- (for internal reference only) 2. MATERIAL INFORMA TION A. Parts Required Per Aircraft (1) Modification Kit 8MK4277 ---001 (2) Detailed Kit Content:

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 5 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 Quantity Per Kit ---001 Part Number Description Remarks

4 82710028 ---951 Rudder Pushrod 2 82710274 ---951 Brake Pushrod 4 AN960D10L Washer 4 AN960D416 Washer 4 AN960D416L Washer 4 MS24665 ---88 Cotter Pin 8 MS24665 ---153 Cotter Pin 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 82710028 ---003 Rudder Pushrod 4 B DIS 82710028 ---951 S 82710274 ---001 Brake Pushrod 2 B DIS 82710274 ---951 S IC Interchangeability Code A Not interchangeable. B Removed Part. No direct replacement. C Conditionally Interchangeable. Installation of superseded part negates the intent of this service bulletin. 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.

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 6 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 PNC Part Number Code N No equivalent Bombardier Inc. part number for reworked part. Indicate on part that this service bulletin has been accomplished. 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 (1) Either pull and clip circuit breakers required to isolate affected circuits or placard and select aircraft electrical power to OFF. Obey all relevant WARNINGS and CAUTIONS detailed in Maintenance Manual PSM 1 ---84 ---2. (2) Remove and retain the following access panels 121AL, 121BL, 122AR and 122BR (refer to PSM 1 ---84 ---2 Chapter 6). B. Procedure
Rudder Control Pushrod Replacement

NOTE: Replace one pushrod at a time. (1) Remove and discard four pushrods 82710028 ---003 from the rudder pedal adjustment assembly on the pilots and co ---pilots side as follows: (a) From the pedal adjustment lever disconnect one side of the pushrod by removing one cotter pin MS24665 ---153, one nut MS14144L4, one washer AN960D416L, one bolt NAS6604D14 and one bushing NAS75 ---4 ---006. Keep all hardware except for washer and cotter pin (refer to Figure 3). (b) From the rudder pedal tube assembly disconnect the other side of the pushrod by removing one cotter pin MS24665 ---153, one nut MS14144L4, one bolt NAS6604D18, one washer AN960D416 and one bushing NAS75 ---4 ---008. Keep all hardware except for washer and cotter pin (refer to Figure 3). (2) After removing each defective Pushrod (P/N 82710028 ---003) cut each part into two pieces in a way that will render them UNSERVICEABLE, wire lock the two pieces together. Tag the parts and dispose them as instructed by your Local Airworthiness Authority.

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 7 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 (3) Install four new pushrods 82710028 ---951 to rudder pedal adjustment assembly on the pilots and co ---pilots side as follows: (a) Install one end of pushrod to the pedal adjustment lever using one new cotter pin MS24665 ---153, one nut MS14144L4, one new washer AN960D416L, one bolt NAS6604D14 and one bushing NAS75 ---4 ---006 (refer to Figure 3). (b) Install the other end of pushrod to the rudder pedal tube assembly using one new cotter pin MS24665 ---153, one nut MS14144L4, one bolt NAS6604D18, one new washer AN960D416 and one bushing NAS75 ---4 ---008 (refer to Figure 3). (4) Rig new pushrods 82710028 ---951 per Maintenance Manual PSM 1 ---84 ---2 Task 27 ---21 ---00 ---830 ---810. Brake Rudder Control Pushrod Replacement (1) Gain access to the brake, rudder control pushrods below the flight compartment floor on the pilots side. (2) Deleted (3) Replace two pushrods 82710274 ---001 from the brake, rudder control assembly on the pilots side as follows: (a) Disconnect both ends of the pushrod by removing two cotter pins MS24665 ---88, two nuts MS14144L3, two washers AN960D10L and two bolts NAS6603D7. Keep all hardware except for washers and cotter pins (refer to Figure 3). (b) After removing each defective Pushrod (P/N 82710274 ---001) cut each part into two pieces in a way that will render them UNSERVICEABLE, wire lock the two pieces together. Tag the parts and dispose them as instructed by your Local Airworthiness Authority. (c) Install new pushrod 82710274 ---951 using two new cotter pins MS24665 ---88, two nuts MS14144L3, two new washers AN960D10L and two bolts NAS6603D7 (refer to Figure 3). (4) Rig the Main Brake Control Cables per Maintenance Manual PSM 1 ---84 ---2 Task 32 ---42 ---00 ---830 ---801. C. Close Out (1) Remove all tools and equipment from the work area. (2) Perform an operational check of the Rudder Control System per Maintenance Manual PSM 1 ---84 ---2 Task 27 ---20 ---00 ---710 ---803.

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 8 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 (3) Perform a functional test of the Main Landing Gear Brake System per Maintenance Manual PSM 1 ---84 ---2 Task 32 ---42 ---00 ---720 ---801. (4) Install access panels 121AL, 121BL, 122AR and 122BR (refer to PSM 1 ---84 ---2 Chapter 6). (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.

Figure 1 VIEW DELETED

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 9 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 Figure 2

### SERVICE BULLETIN 84 ---27 ---21

S.B. 84 ---27 ---21 Page 10 of 10 10 Oct 2008 LS Revision ’A’, 22 Mar 2011 View Looking Inboard on LH Side (RH Side Similar) Figure 3 COTTER PIN MS24665 ---153 4 REQUIRED WASHER AN960D416 4 REQUIRED

COTTER PIN MS24665 ---88 4 REQUIRED WASHER AN960D10L 4 REQUIRED (BOLT MS14144L3) (NUT NAS6603D7)

PUSHROD ---RUDDER 82710028 ---951 4 REQUIRED

PUSHROD ---BRAKE 82710274 ---951 2 REQUIRED COTTER PIN MS24665 ---153 4 REQUIRED WASHER AN960D416L 4 REQUIRED

1Jan 2009 SERVICE BULLETIN (SB) --- RECORD OF INCORPORATION --- Q SERIES DASH 8 AIRCRAFT To: Partner Data Co ---Ordinator (Toronto), Bombardier Aerospace Commercial Aircraft Phone: (1) 416 375 3534 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 VWeight and Balance V Electrical Load VTooling 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 VJob Set ---Up V Procedure V Close---Out VTest 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