# Bombardier Service Bulletin 8-27-110 Copy: U.S. DOT/FAA - Service Information - 1 ("U.S. DOT/FAA - Service Information - 1"), 11 pages: PDF https://openairdocs.org/files/sha256/c0/5e/c05ed392802e0eea9499cf4998e906672ff9853c2fc650e911a49f60d4c46ab9; text https://openairdocs.org/service-documents/bombardier/sb-8-27-110/file/c05ed392802e.md. Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2011-1230; AD 2012-04-08 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: 8-27-110 - Latest revision known: 8-27-110, Revision C, dated May 13, 2011 (OpenAirDocs) - Page: https://openairdocs.org/service-documents/bombardier/sb-8-27-110 ## ADs that cite it (1) (OpenAirDocs) Newest first, with the revision each names, as OpenAirDocs read it from the AD's text. - [AD 2012-04-08](https://openairdocs.org/ad/2012-04-08.md), effective Apr 10, 2012: Revisions A, B and C Also cited in [1 proposed AD](https://openairdocs.org/service-documents/bombardier/sb-8-27-110/proposed.md). ## Text (11 pages) Rights: © Bombardier Inc. Filed by the FAA in regulations.gov docket FAA-2011-1230; AD 2012-04-08 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. This text is 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. ### Page 1 (OCR) DHC-8 (DASH 8) SERVICE BULLETIN 8-27-110 Flight Control - Rudder Power Control Unit (PCU) Mounting bracket Fatigue Cracking - ModSum 8Q101890 This page transmits Revision 'C' of Service Bulletin 8-27-110, pages 1 thru 10 dated: 13 May 2011. This service bulletin is re- issued in its entirety for the reasons that follow: - the Publications Affected section is revised to add the Airplane Flight Manual - the References section is revised to convey the latest revision of the service bulletin and engineering documentation e Compliance in the previous issues of this service bulletin is not affecte / this revision. No additiona rework to the aircraft is introduced ov th revision. Remove previous issue of this Service Bulletin and replace with attached. Previous issues of Service Bulletin 8-27-110: Initial issue - Pages 1 thru 10 dated 12 Nov 2010 Revision 'A' - Pages 1 thru 10 dated 03 Dec 2010 Revision 'B' - Pages 1 thru 10 dated 31 Jan 2011 Revision 'C' 13 May 2011 ### Page 2 (OCR) de HAVILLAND BOMBARDIER DASH8 SERVICE BULLETIN Customer. Support ATA SYSTEM: 2720 NUMBER: 8-27-110 BOMBARDIER AEROSPACE REGIONAL AIRCRAFT CONSIDER THIS SERVICE BULLETIN TO BE PARTICULARLY SIGNIFICANT AND URGES OPERATORS TO PROMPTLY EVALUATE THE CONTENTS SUBJECT: Flight Control - Rudder Power Control Unit (PCU) Mounting Bracket Fatigue Cracking - ModSum 8Q101890 PLANNING INFORMATION A. Effectivity Aircraft Affected: In-Service: DHC-8 Aircraft Models 102, 103, 106, 201, 202, 301, 311, 314 and 315 Serial Numbers 003 thru 672. 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. 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 1 of 10 JR ### Page 3 (OCR) SERVICE BULLETIN 8-27-110 Part Number Description 72760059-101 Mounting Adapter B. Reason Problem: Several operators have reported that mounting adapter 72760059-101 was found cracked during a general visual inspection of the aft spar of the vertical stabilizer. Cause: Initial investigation has identified that the component has been under-designed based on the static and endurance loading conditions. Solution: ModSum 8Q101890 installs a new CRES mounting adapter 82760165-101 to the existing PCU and rear spar mount locations. C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: - aircraft electrical power is removed - aircraft nose landing gear is locked and verified lock is engaged - main landing gear lock pins are installed thru each main gear and main gear door mechanism - work stands are set up beside the vertical stabilizer - access panels are opened - a rigging pin is inserted through feel unit arm - electrical connectors are disconnected - hydraulic lines are disconnected and capped - the rudder actuator is removed from the mounting adapter - the existing aluminum mounting adapter is then removed and discarded - a new CRES mounting adapter is installed with new bolts - existing rudder actuator is installed with new bolts and new countersunk washers - new bolts are torqued and secured as required - caps are removed and hydraulic lines are reconnected to actuator fittings - electrical connectors are installed - a check of spring strut rigging is done 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 2 of 10 JR ### Page 4 (OCR) SERVICE BULLETIN 8-27-110 - rigging pin is removed and an operational test of the rudder pressure regulator and the rudder actuator isolate solenoid valves is done - an operational test of the rudder control system is done - access panels are installed - close out. D. Compliance Bombardier Inc. highly recommend that ModSum 8Q101890 be incorporated 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 (DTS). F. Manpower It will take an estimated 4.5 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 1.00 Procedure 1.50 Test / RTS 1.00 Close-Out 1.00 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 ModKit 8MK4403-001 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: 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 3 of 10 JR ### Page 5 (OCR) SERVICE BULLETIN 8-27-110 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 8MK4403-001 Retrofit Kit Mounting Adapter PCU - Rudder H. Tooling - Price and Availability None I. Weight and Balance Moment A/C Type and Weight (Lb) Arm (Inches) (Inches x Lb) Model × 0.001 DHC-8 Model 102 1.87 829.34 1.55 DHC-8 Model 103 1.87 829.34 1.55 DHC-8 Model 106 1.87 829.34 1.55 DHC-8 Model 201 1.87 829.34 1.55 DHC-8 Model 202 1.87 829.34 1.55 DHC-8 Model 301 1.87 891.34 1.67 DHC-8 Model 311 1.87 891.34 1.67 DHC-8 Model 314 1.87 891.34 1.67 DHC-8 Model 315 1.87 891.34 1.67 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 4 of 10 JR ### Page 6 (OCR) SERVICE BULLETIN 8-27-110 J. Electrical Load Data Not affected K. Publications Affected Flight Manual............................... PSM 1-81-1A and PSM 1-82-1A and PSM 1-83-1A Dash 8 Illustrated Parts Catalogue .................... PSM 1-8-4 and PSM 1-82-4 and PSM 1-83-4 Weight and Balance Manuals PSM 1-8-8 and PSM 1-82-8 and PSM 1-83-8 Modifications Manual . PSM 1-813-12 References Revision 'C' of this service bulletin was prepared to the engineering drawings and related data that follows: DRAWING SHEET REV 8MK4403 - - 8Z5926 1 ModSum 8Q101890 Rev. 'A' PCA 6303 Revision 0 (for internal reference only) Transport Canada Airworthiness Directive Pending 2. MATERIAL INFORMATION A. Parts Required Per Aircraft (1) Modification Kit 8MK4403-001 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 5 of 10 JR ### Page 7 (OCR) SERVICE BULLETIN 8-27-110 (2) Detailed Kit Content: Quantity Per Kit Part Number Description Remarks -001 2 82760165-101 Mounting Adapter 1 8Z5926-001 Rework- InstI Drawing (3) In addition to the above parts), the following material(s) are 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 Part Number Qty. Per Aircraft Description Remarks MS21299C4 8 Washer Countersunk NAS1304-14 8 Bolt See Note Below MS21250H04010 8 Bolt Deleted MS20995C32 A/R Lockwire 0.032 inch Diameter MIL-C-16173 1 Ounce Corrosion Grade 2 Preventative Compound NOTE: Part number NAS6604-14 can be used as an acceptable alternate for part number NAS1304-14. B. Parts Required to Modify Spares None 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 6 of 10 JR ### Page 8 (OCR) SERVICE BULLETIN 8-27-110 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 Existing New Part Part Number Description Qty. IC DC Number PNC 72760059-101 Adapter 2 DIS 82760165-101 S IC Interchangeability Code 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. PNC Part Number Code N No equivalent Bombardier Inc. part number for reworked part. Indicate on part that this service bulletin has been accomplished. Part number after rework. Superseding or equivalent part number. Reworked part and superseding part are functionally and physically equivalent but not identical. 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 7 of 10 JR ### Page 9 (OCR) SERVICE BULLETIN 8-27-110 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set-Up NOTE: It is strongly recommended to do the retrofit work indoors, to avoid inadvertent rudder movement due to wind gusts. (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 thru each main gear and main gear door mechanism. (3) Make sure the nose gear ground lock is engaged. (4) Set up the work platforms or ladders as required to gain access to the vertical stabilizer. Make sure the work platforms or ladders are electrically grounded. WARNING: OBEY ALL HYDRAULIC SAFETY PRECAUTIONS WHEN YOU DO WORK ON THE HYDRAULIC SYSTEM AND/OR A HYDRAULIC SYSTEM COMPONENT. IF YOU DO NOT DO THIS, INJURY TO PERSONNEL AND/OR DAMAGE TO EQUIPMENT CAN OCCUR. B. Procedure Remove upper and lower PCU actuators. Refer to applicable Aircraft Maintenance Manual PSM 1-8-2, Chapter 27-20-36, Aircraft Maintenance Manual PSM 1-82-2, Chapter 27-20-36, TASK 27-20-36-000-801 and Aircraft Maintenance Manual, PSM 1-83-2, Chapter 27-20-36. Ease the rudder fully to the left. Block the rudder to prevent it from moving. Remove and discard existing mounting adapter 72760059-101, existing bolts MS21250H04008 and bolts NAS1304-13. Retain washers AN960D416L. Refer to Figure 1. NOTE: Rudder removal is not required to access the adapter mounting nuts. It is recommended to use flexible socket extensions and/or universal joints to ease nut and bolt access. Two technicians are recommended for this step. Install new mounting adapter 82760165-101, with new bolts MS21250H04010, bolts NAS1304-14 and washers (countersunk) MS21299C4 in accordance with instructions in drawing 825926. 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 8 of 10 JR ### Page 10 (OCR) SERVICE BULLETIN 8-27-110 NOTE: Part number NAS6604-14 can be used as an acceptable alternate for part number NAS1304-14. NOTE: Install one new washer MS21299C4 under each bolt head MS21250H04010 (countersink facing bolt head). Install existing PCU actuators. Refer to applicable Aircraft Maintenance Manual PSM 1-8-2, Chapter 27-20-36 and Chapter 29-00-00, Aircraft Maintenance Manual PSM 1-82-2, Chapter 27-20-36, TASK 27-20-36-400-801 and Aircraft Maintenance Manual PSM 1-83-2, Chapter 27-20-36 and Chapter 29-00-00. Rig the upper and lower spring struts. Refer to applicable Aircraft Maintenance Manual, Chapter 27-20-00. Do the operational test of the rudder pressure regulator and the rudder actuator isolate solenoid valves. Refer to applicable Aircraft Maintenance Manual, Chapter 27-20-38. Do the operational test of the rudder control system. Refer to applicable Aircraft Maintenance Manual, Chapter 27-20-00. C. Close Out (1) Remove all tools and equipment from the work area. On incorporation of this ModSum/Modification, add the weight and balance data shown in Section I of this service bulletin to the Weight and Balance Manual PSM 1-8-8 or PSM 1-82-8 or PSM 1-83-8. Under 'Description of Change' enter "ModSum 8Q101890 incorporated." On incorporation of this ModSum, make an entry that conforms to local regulatory requirements in the applicable logbooks). Enter component serial numbers if applicable. Enter this ModSum number only after complete and functional incorporation of all work defined in this service bulletin. 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 9 of 10 JR ### Page 11 (OCR) SERVICE BULLETIN 8-27-110 M/SPAR DATUM FRONT SPAR REAR SPAR DATUM DATUM RIB #11A DATUM RIB #9 DATUM A RIB #8 DATUM NOW BOLT MS21250H04010 ACTUATOR RUDDER WASHER MS21299C4 WAS ASSEMBLY LOCK WIRE MOUNTING ADAPTER MS20995C32 72760059-101 NOW RIB #9 C MOUNTING ADAPTER DATUM 82760165-101 ACCESS WASHER (RETAINED) PANEL AN960D416L 332DL NUT (RETAINED) MS21042-4 DATUM RIB #8 ~ BOLT - NAS1304-14 OR NAS6604-14 WASHER (RETAINED) - DETAIL A AN960D416L NOTE: USE ONE WASHER MS21299C4 UNDER EACH BOLT HEAD MS21250H04010 (COUNTER SINK FACING BOLT HEAD). Installation of New Mounting Adapter Figure 1 12 Nov 2010 S.B. 8-27-110 Revision 'C' 13 May 2011 Page 10 of 10 JR --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). 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