# D

S.B. 84 ---27 ---60

Page 1 of 14 12 Jul 2012 JR 

# SERVICE BULLETIN Customer Support
ATA SYSTEM: 2700 NUMBER: 84 ---27 ---60 

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

SUBJECT: Flight Controls --- Rudder Feel and Trim Unit (RFTU) Spring Trunnion Seizure --- 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 4392, 4394 thru 4397, 4399 thru 4402, 4404 and 4405 with Parker RFTU P/N 399500 ---1007 containing serial numbers 0008 thru 0509, including serial numbers with suffix ---‘A’. Aircraft serial numbers 4393, 4398, 4403, 4406 and subsequent have conformal RFTUs installed in production. 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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S.B. 84 ---27 ---60 Page 2 of 14 12 Jul 2012 JR 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 Parker 399500 ---1007 (see Note) Rudder Feel and Trim Unit (RFTU) NOTE: Affected serial numbers 0008 thru 0509, including serial numbers with suffix ---‘A’.

B. Reason Problem: A process error was found where cadmium plating on the spring trunnion bushing within the RFTU assembly was not removed. The cadmium was found to cause galvanic corrosion in the trunnion joint. SB 84 ---27 ---57 was issued to address this concern, however, following further investigation it was found that: --- Some bushings with ID cad plating removed, have developed corrosion. --- RFTU’s assembled at one of the manufacturers facilities were found to have grease omitted from the trunnions and centre shaft during the assembly of the unit. As a result, this condition could cause a momentary bind or stiff rudder pedal operation. As a result serial numbers 0008 thru 0509, including serial numbers with suffix ---‘A’ are considered affected. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: --- maintenance records are checked for the RFTU serial number --- No. 1 and No. 2 hydraulic systems are depressurized --- aircraft electrical power is removed and placards are installed in the flight compartment --- aircraft nose landing gear is locked and verified lock engaged --- main landing gear lock pins are installed through each main gear and main gear door mechanism --- safety stands are placed near the vertical stabilizer

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S.B. 84 ---27 ---60 Page 3 of 14 12 Jul 2012 JR --- access panel 322DL is removed --- RFTU is visually inspected for serial number range shown in Effectivity section of this service bulletin and any sign of seizure or rough movement of the trunnion or centre shaft --- if any sign of seizure or rough movement of the trunnion or center shaft is found, RFTU is replaced with an unaffected unit --- identified RFTU is lubricated on the bushing/trunnion interface and centre shaft assembly within 200FH and repeated every 600FH --- if the RFTU serial number is outside the affected range or the serial number has suffix ‘B’, no further action is required. Close Out section is completed --- all affected RFTU’s are to be returned to Parker for rework within 6000FH --- these units will be identified to a “B” suffix after rework --- an operational check of the rudder system is done --- close out.

NOTE: This service bulletin aggregates the intent of Parker service bulletins 399500 ---27 ---001, 399500 ---27 ---002 and 399500 ---27 ---003. As a result, the component effectivity listed in section 1.A. of this service bulletin is a superset of the effectivity listed in 399500 ---27 ---003. D. Compliance Bombardier Inc. recommends lubricating the affected RFTU’s within 200FH and repeating every 600FH in accordance with this service bulletin. Modsums IS4Q2700017 and IS4Q2750008 provide an equivalent procedure for lubricating the RFTU. Aircraft currently being lubricated per modsum IS4Q2700017 or IS4Q2750008 is recommended to comply with this service bulletin at its next 600FH lubrication interval. All affected RFTU’s are recommended to be returned to Parker for rework within 6000FH. An Airworthiness Directive from Transport Canada is pending.

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S.B. 84 ---27 ---60 Page 4 of 14 12 Jul 2012 JR 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). F. Manpower PART A --- Special Inspection of RFTU for S/N and any sign of seizure of the trunnion or center shaft It will take an estimated 2.0 man ---hours to complete PART A of the ACCOMPLISHMENT instructions in this service bulletin. The breakdown of man ---hours is shown in the table that follows: TASK MAN ---HOURS Job Set ---Up 0.50 Procedure in Part A 1.00 Test / RTS 0.00 Close ---Out 0.50 PART B --- Replacement of the RFTU It will take an estimated 17.0 man ---hours to complete PART B of the ACCOMPLISHMENT instructions in this service bulletin. The breakdown of man ---hours is shown in the table that follows: TASK MAN ---HOURS Job Set ---Up 2.50 Procedure in Part B 11.00 Test / RTS 1.00 Close ---Out 2.50

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S.B. 84 ---27 ---60 Page 5 of 14 12 Jul 2012 JR PART C --- Lubrication of RFTU if the spring trunnion or center shaft are not found seized and the RFTU is within the affected range It will take an estimated 3.0 man ---hours to complete PART C of the ACCOMPLISHMENT instructions in this service bulletin. The breakdown of man ---hours is shown in the table that follows: TASK MAN ---HOURS Job Set ---Up 0.50 Procedure in Part C 1.00 Test / RTS 1.00 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 Direct labor costs to do this service bulletin are covered by Parker up to a maximum of 17 hours for each aircraft. G. Material --- Price and Availability This repair is available upon release of this Service Bulletin, at no charge for the affected S/N range, with a Turn ---Around ---Time (TAT) of 20 days after receipt of the RFTU and purchase order. Return the affected RFTU to Parker Hannifin Corporation at the address listed below. PARKER HANNIFIN CORPORATION Customer Support Inc 14300 Alton Parkway Irvine, CA 92618 ---1898 USA PHONE: (949) 833 ---3000 FAX: (949) 809 ---8390 REPAIR STATION NO.: AU4R063M Operators are requested to contact their respective Parker Hannifin Customer Service Administrator to schedule implementation of this Service Bulletin.

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S.B. 84 ---27 ---60 Page 6 of 14 12 Jul 2012 JR The prices and provisions contained in this Service Bulletin are valid for 24 months after the Initial Issue of this document. They only apply to the work scope outlined in this Service Bulletin and do not include any other necessary repairs. After that date, request a quotation from Parker Hannifin Corporation, Customer Support. 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

.................... Maintenance Requirement Manual PSM 1 ---84 ---7

.................... 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: InService ModSum IS4Q2700017/IS4Q2750008 PCA 44072 Revision 0 (for internal reference only) Parker Service Bulletin 399500 ---27 ---001 Parker Service Bulletin 399500 ---27 ---002 Parker Service Bulletin 399500 ---27 ---003 Transport Canada Airworthiness Directive CF ---2012 ---02. 2. MATERIAL INFORMA TION A. Parts Required Per Aircraft

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S.B. 84 ---27 ---60 Page 7 of 14 12 Jul 2012 JR (1) The following material is required for the completion of this service bulletin and may be procured as single items from Bombardier Aerospace Regional Aircraft or purchased directly from industry sources. Addresses of manufacturers and suppliers not shown below are listed in either Maintenance Manual Chapter 20 or in Structural Repair Manual Chapter 51 or, for 400 Series Aircraft, in Consumable Products Manual PSM 1 ---84 ---18.

Part Number Qty. Per Aircraft Description Remarks LPS ---2 as required Lubricant commercially available EXTEND ---A ---LUBE Super Straws or commercially available equivalent B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None D. Existing Parts Accountability None 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set ---Up NOTE: Before starting work, inspect all maintenance records to determine the RFTU serial number. (0008 thru 0509, including serial numbers with suffix ---‘A’). If the unit serial number is outside the affected range or the serial number has suffix ‘B’, no further action is required. Go to Close Out section.
WARNING: INSTALL THE SAFETY DEVICES, THE WARNING SIGNS, AND THE WARNING PLACARDS BEFORE YOU START A PROCEDURE ON OR AROUND:

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S.B. 84 ---27 ---60 Page 8 of 14 12 Jul 2012 JR FLIGHT CONTROLS . FLIGHT CONTROL SURFACES . COMPONENTS THAT MOVE .MAKE SURE THAT THERE ARE NO PERSONS OR EQUIPMENT ON OR NEAR THE SURFACES OF THE FLIGHT CONTROLS, ACCIDENTAL MOVEMENT OF THE FLIGHT CONTROLS CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF THE MOVEMENT OF FLIGHT CONTROL SURFACES. MOVEMENT OF THE FLIGHT CONTROL SURFACES CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. WARNING: BE SURE THAT THE HYDRAULIC IS OFF, AND THAT THERE IS NO PRESSURE IN THE HYDRAULIC SYSTEM. IF YOU DO NOT DO THIS YOU CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO THE EQUIPMENT. (1) Make sure that lock pins are installed through main landing gear and nose gear. (2) Depressurize No.1 and No.2 hydraulic systems (Refer to Aircraft Maintenance Manual PSM, 1 ---84 ---2, TASK 29 ---00 ---00 ---863 ---802). (3) Placard and select all aircraft electrical power to OFF. Obey all relevant WARNINGS and CAUTIONS detailed in Maintenance Manual PSM 1 ---84 ---2. Refer to Aircraft Maintenance Manual PSM 1 ---84 ---2, TASK 24 ---00 ---00 ---861 ---802, TASK 24 ---00 ---00 ---910 ---801(electrical/electronic safety precautions) and TASK 24 ---00 ---00 ---910 ---802 (electrostatic discharge safety precautions). (4) Install workstands near the vertical stabilizer, as required. Make sure the workstands are electrically grounded. (5) Remove and retain access panel 322DL with existing hardware. B. Procedure PART A --- Special Inspection of RFTU for S/N and any sign of seizure of the trunnion or centre shaft.

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S.B. 84 ---27 ---60 Page 9 of 14 12 Jul 2012 JR (1) Do a visual inspection on RFTU for serial number, (Refer to Effectivity section of this service bulletin for affected component serial number range). (2) If the unit serial number is outside the affected range or the serial number has suffix ‘B’, no further action is required. Go to Close Out section. (3) Slowly operate the rudder controls and observe the RFTU. Check for any sign of seizure or rough movement of the trunnion and centre shaft. If any sign of seizure or rough movement of the trunnion or centre shaft is found, Do part B of the Procedure

. (4) If the unit serial number is within the affected range and no sign of seizure or rough movement of the trunnion or centre shaft is found, Do part C of the Procedure

. PART B --- Replacement of the RFTU.

NOTE: As of the effective date of this service bulletin , do not attempt to lubricate a unit which has been found to be seized. Return the unit to Parker for repair
. (1) Replace the existing RFTU with a new RFTU (Refer to Aircraft Maintenance Manual PSM, 1 ---84 ---2, TASK 27 ---22 ---06 ---000 ---801 and TASK 27 ---22 ---06 ---400 ---801). (2) Go to the Close Out section of this service bulletin. (3) Return the removed RFTU to Parker as per Material --- Price and Availability section of this service bulletin. PART C --- Lubrication of RFTU if the spring trunnion or center shaft are not found seized and the RFTU is within the affected range. (1) Shield the RFTU and surrounding structure to prevent LPS ---2 overspray and fluid pooling in the area shown in Figure 1. (2) Apply the lubricant LPS ---2 to the RFTU ’s as follows: (a) Apply LPS ---2 to the bushing/trunnion interface in locations shown in Figure 3. (b) Apply three short blasts (approximately 0.5 second per blast) of LPS---2 lubricant to each of the bushing at the joint (one blast in each direction) in the trunnion/flanged bushing interface while masking the remainder of the assembly to limit the lubricant coverage to these areas only. Refer to Figure 2. (c) Apply a small lateral load by hand to the springs at least five times in the method shown in Figure 4.

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S.B. 84 ---27 ---60 Page 10 of 14 12 Jul 2012 JR (d) Access the RFTU centre shaft and lubricate at the points shown in Figure 5. (e) Once the lubricant has been applied, make sure to help spread the lubricant around the joints by cycling rudder pedals (either pilot or co ---pilot side) ten times slowly in each direction (approximately 15 seconds to reach full travel in each pedal). NOTE: The RFTU may have been lubricated previously with lubricant LPS ---1. Lubricant LPS ---2 may be applied over the existing lubricant LPS ---1 in the spring /trunnion joints. (3) Complete the Close Out section of this service bulletin. C. Close Out (1) Install access panel 322DL. (2) Do the operational check of the rudder control system (Refer to Aircraft Maintenance Manual, PSM 1 ---84 ---2, TASK 27 ---20 ---00 ---710 ---802). (3) Remove all tools and equipment from the work area. (4) On completion of this service bulletin, make the following entry in the appropriate logbooks: “Service Bulletin 84 ---27 ---60, Flight Controls --- Rudder Feel and Trim Unit (RFTU) --- Spring Trunnion Seizure --- Special Inspection and Rectification accomplished.”

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S.B. 84 ---27 ---60 Page 13 of 14 12 Jul 2012 JR Figure 5

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