# Bombardier Service Bulletin 84-27-60

Copy: No revision named ("U.S. DOT/FAA - SB 84-27-60"), 14 pages: PDF https://openairdocs.org/files/sha256/68/92/68920b17517c3237352a1b67c24bfdd6ae2ca4a5cfefe5998e92db8480ff0725; text https://openairdocs.org/service-documents/bombardier/sb-84-27-60/file/68920b17517c.md. Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2012-0594; AD 2013-22-09 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: 84-27-60
- Page: https://openairdocs.org/service-documents/bombardier/sb-84-27-60

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

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

- [AD 2013-22-09](https://openairdocs.org/ad/2013-22-09.md), effective Dec 5, 2013: No revision named

Also cited in [1 proposed AD](https://openairdocs.org/service-documents/bombardier/sb-84-27-60/proposed.md).

## Text (14 pages)

Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2012-0594; AD 2013-22-09 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N.

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SERVICE BULLETIN
Customer
Support
ATA SYSTEM: 2700 NUMBER: 84- - -27- - -60
BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS
SERVICE BULLETIN TO BE PARTICULARL Y SIGNIFICANT AND
URGES OPERATORS TO PROMPTL Y 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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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 wher e 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 insta lled through each main gear and main gear
door mechanism
- - - safety stands are placed near the vertical stabilizer

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- - - 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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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).
F. M a n p o w e r
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 s ervice bulletin. The breakdown of 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 0.50
Procedure in Part A 1.00
T e s t/R T S 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 s ervice bulletin. The breakdown of 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 2.50
Procedure in Part B 11.00
T e s t/R T S 1.00
Close- - -Out 2.50

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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 s ervice bulletin. The breakdown of 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 0.50
Procedure in Part C 1.00
T e s t/R T S 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 T echnical Help
Desk by telephone at 416- - -375- - -4000 or email at : thd.qseries@aero.bombardier.com
D i r e c tl a b o rc o s t st od ot h i ss e r v i c eb u l l e t i na r ec o v e r e db yP a r k e ru pt oa
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
a f f e c t e d S / N r a n g e , w i t h a Tu r n --- A r o u n d --- T i m e ( T A T ) o f 2 0 d a y s a f t e r r e c e i p t o f t h e
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 impl ementation of this Service Bulletin.

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The prices and provisions contained in thi s 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. 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....................
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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(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 --- 8 4 --- 1 8 .
Part Number Qty. Per Aircraft Description Remarks
L P S --- 2 as required Lubricant commercially avail-
able
E X T E N D --- A --- L U B E
Super Straws
or commercially
available equivalent
B. Parts Required to Modify Spares
None
C. Special T ools and Equipment Required
None
D. Existing Parts Accountability
None
3. ACCOMPLISHMENT INSTRUCTIONS
A . J o b S e t --- U p
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
r e q u i r e d .G ot oC l o s eO u tsection.
WARNING: INSTALL THE SAFETY DEVICES, THE WARNING SIGNS, AND THE
WARNING PLACARDS BEFORE YOU START A PROCEDURE ON OR
AROUND:

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FLIGHT CONTROLS
. FLIGHT CONTROL SURFACES
. COMPONENTS THAT MOVE
. M A K ES U R ET H A TT H E R EA R EN OP E R S O N SO RE Q U I P M E N TO N
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
p r e c a u t i o n s ) a n d T A S K 2 4 --- 0 0 --- 0 0 --- 9 1 0 --- 8 0 2 ( e l e c t r o s t a t i c d i s c h a r g e s a f e t y
precautions).
(4) Install workstands near the vertica l 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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(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 ) G ot ot h e 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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(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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### Page 12 (OCR)

SERVICE BULLETIN 84-27-60
Bushing/Trunnion Interface,
2 Places in 2 Locations
Figure 3
Resulting Trunnion Rotation
From Lateral Load
Resulting Trunnion Rotation
From Lateral Load
Apply Load
Figure 4
12 Jul 2012  S.B. 84-27-60
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SERVICE BULLETIN 84-27-60
Figure 5
12 Jul 2012  S.B. 84-27-60
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