# Bombardier Service Bulletin 84-27-53 Copy: No revision named ("U.S. DOT/FAA - Service Information"), 12 pages: PDF https://openairdocs.org/files/sha256/97/13/971376d4d5a959b7c793069c38798f5303836339b185e532e6814a6f94009c26; text https://openairdocs.org/service-documents/bombardier/sb-84-27-53/file/971376d4d5a9.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: 84-27-53 - Page: https://openairdocs.org/service-documents/bombardier/sb-84-27-53 ## 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: No revision named Also cited in [1 proposed AD](https://openairdocs.org/service-documents/bombardier/sb-84-27-53/proposed.md). ## Text (12 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) de HAVILLAND BOMBARDIER DASH8 SERVICE BULLETIN Customer_ Support ATA SYSTEM: 2721 NUMBER: 84-27-53 SUBJECT: Flight Controls - Retrofit Empennage - New Rudder PCU Mounting Adapter - ModSum 4-113655 1. PLANNING INFORMATION A. Effectivity Aircraft Affected: In-Service: DHC-8 Aircraft Models 401 and 402 Serial Numbers 4001 thru 4343. 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 Reason Problem: The current rudder Power Control Unit (PCU) mounting adapters have been found to be inadequately designed and have the possibility of cracking. Solution: This Mod replaces the current rudder PCU mounting adapters with a redesigned adapter. 26 Nov 2010 S.B. 84-27-53 Page 1 of 10 JR ### Page 2 (OCR) SERVICE BULLETIN 84-27-53 C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: - 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 panels are opened - the upper and lower rudder PC's are removed - the PC's mounting adapters are removed and discarded - new mounting adapters are installed - the rudder PCU's are re-installed - the rudder PCU's are rigged - an operational test of the rudder control system is done - close out. D. Compliance Bombardier Inc. recommends incorporation of ModSum 4-113655 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). 26 Nov 2010 S.B. 84-27-53 Page 2 of 10 JR ### Page 3 (OCR) SERVICE BULLETIN 84-27-53 F. Manpower It will take an estimated 9.50 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 0.15 Procedure 8.00 Test / RTS 1.00 Close-Out 0.15 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 8MK4437-001 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 Bivd. Toronto Ontario Canada M3K-1Y5 Facsimile: (416) 375-3060 Telephone : (416) 375-3920 Kit Number Description 8MK4437-001 Retrofit Kit Mounting Adapter PCU - Rudder H. Tooling - Price and Availability None 26 Nov 2010 S.B. 84-27-53 Page 3 of 10 JR ### Page 4 (OCR) SERVICE BULLETIN 84-27-53 . 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: DRAWING SHEET REV 8MK4437 1 - - 8Z6854 1 A ModSum 4 - 123100 Rev. 'A' ModSum 4Y123100 Rev. 'A' ModSum 4Q113655 Rev. 'D' ModSum 4-113655 Rev. 'D' PCA 42433 Revision 0 (for internal reference only) Transport Canada Airworthiness Directive Pending 2. MATERIAL INFORMATION A. Parts Required Per Aircraft (1) Modification Kit 8MK4437-001 (2) Detailed Kit Content: 26 Nov 2010 S.B. 84-27-53 Page 4 of 10 JR ### Page 5 (OCR) SERVICE BULLETIN 84-27-53 Quantity Per Kit Part Number Description Remarks -001 8 NAS1149D0432J Washer see Note 1 as required MS20995C32 Lockwire see Note 1 8 MS21042L4 Nut see Note 1 8 MS20002C4 Washer see Note 1 8 NAS1149D0416J Washer see Note 1 8 MS21250H04006 Bolt see Note 1 8 NAS6604-15 Bolt see Note 1 2 82760351 - 105 Adapter NOTE 1: These items are required to install the kit and are not included in the kit and must be supplied by operator. (3) In addition to the above parts), the following materials) 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 51 or, for 400 Series Aircraft, in Consumable Products Manual PSM 1-84-18. Part Number Qty. Per Aircraft Description Remarks F13 Grade 2 as required Corrosion Preven- MIL-PRF-16173 tion Compound Grade 2 B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None 26 Nov 2010 S.B. 84-27-53 Page 5 of 10 JR ### Page 6 (OCR) SERVICE BULLETIN 84-27-53 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 New Part Part Number Description Qty. IC DC Number PNC 82760351 - 101 Adapter 2 DIS 82760351-105 S OR 82760351 - 103 Adapter 2 A DIS 82760351-105 S IC Interchangeability Code Not interchangeable. 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. R Part number after rework. Superseding or equivalent part number. Reworked part and superseding part are functionally and physically equivalent but not identical. 3. ACCOMPLISHMENT INSTRUCTIONS A. Job Set-Up (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. 26 Nov 2010 S.B. 84-27-53 Page 6 of 10 JR ### Page 7 (OCR) SERVICE BULLETIN 84-27-53 (3) Make sure the nose gear ground lock is engaged. NOTE: It is strongly recommended to do the retrofit work indoors, to avoid inadvertent rudder movement due to wind gusts. (4) Set up the work platforms or ladders as required to gain access to the rudder PCU's. Make sure the work platforms or ladders are electrically grounded. B. Procedure (1) Remove access panels 322DL, 322DR, 323BR and 323CR. Refer to Maintenance Manual Task 06-41-00-992-804 and Figure 1. (2) Remove upper and lower rudder Power Control Unit (PCU). Refer to Maintenance Manual Task 27-21-26-000-801. Discard existing hardware. (3) Ease the rudder fully to the left. Block the rudder to prevent it from moving. (4) Remove upper and lower adapter mount 82760351-101 or -103. Discard existing hardware. 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. Replace upper and lower adapter mounts with new adapter mount 82760351-105. (б) Solvent clean faying surfaces between rudder PCU and adapter mount and near spar for electrical bonding through direct contact. refer to Structural Repair Manual Task 51-80-00-02-01. (7) Use eight NAS6604-15 bolts, eight NAS1149D0416J washers and eight MS21042L4 nuts to attach adapter mount to rear spar. Use one NAS1149D0432J washer under each bolt head. Apply torque to 80 inch pounds per Maintenance Manual Task 20-10-01-430-801. Apply Corrosion Prevention Compound F13 Grade 2 to bolt shank. Refer to Figure 2. Use eight MS21250H04006 bolts and eight MS20002C4 washers to attach adapter mount to PCU. torque to 80 inch pounds per Maintenance Manual Task 20-10-01-430-801. (Countersink side of washer facing bolt head). Refer to Figure 2. (9) Secure MS21250H04006 bolts using lockwire MS20995C32. 26 Nov 2010 S.B. 84-27-53 Page 7 of 10 JR ### Page 8 (OCR) SERVICE BULLETIN 84-27-53 (10) Install upper and lower rudder PCU's. Refer to Maintenance Manual Task 27-21-26-000-801. (11) Rig the rudder PCU's. Refer to Maintenance Manual Task 27-21-26-830-801. (12) Do an operational test of the rudder control system. Refer to Maintenance Manual Task 27-20-00-710-802. C. Close Out (1) Remove all tools and equipment from the work area. (2) 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. Remove Temporary Amendment No.18 from Airplane Flight Manual PSM 1-84-1A. 26 Nov 2010 S.B. 84-27-53 Page 8 of 10 JR ### Page 9 (OCR) SERVICE BULLETIN 84-27-53 (M/SPAR DATUM) - (F/SPAR DATUM) - (R/SPAR DATUM) TREATMAS DETAIL A ACCESS PANEL 322DL Looking Inboard on Vertical Stabilizer Figure 1 26 Nov 2010 S.B. 84-27-53 Page 9 of 10 JR ### Page 10 (OCR) SERVICE BULLETIN 84-27-53 BOLT MS21250H04006 LOCKWIRE MS20995C32 WASHER MS20002C4 8 REQUIRED RUDDER ACTUATOR ASSEMBLY- — RIB #9 DATUM ADAPTER MOUNT 82760351-105 RIB #8 DATUM ADAPTER MOUNT 82760351-105 BOLT NAS6604-15 WASHER NAS1149D0416J WASHER NAS1149D0432J (under bolt head) NUT MS21042L4 8 REQUIRED DETAIL A Figure 2 26 Nov 2010 S.B. 84-27-53 Page 10 of 10 JR ### Page 11 (OCR) BOMBARDIER 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.com Jan 2009 ### Page 12 (OCR) BOMBARDIER 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 boxes) 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 • Effectivity • Reason • Description • Compliance • Approval • Manpower • Material • Weight and Balance • Electrical Load • Tooling • References • Publications Affected 2. MATERIAL INFORMATION • Kit Content • Special Tools/Equipment • Parts to Modify Spares • Consumables • Disposition of Existing Parts • Other 3. ACCOMPLISHMENT INSTRUCTIONS • Job Set-Up • Procedure • Close-Out • Test • Illustration(s) • Other 4. COMMENTS, REMARKS, SUGGESTIONS Fax this sheet to (1) 416 375 4538 or Email PDF to: syed.rizvi@aero.bombardier.com Fab 2008 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.