# D

S.B. 84 ---30 ---14

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# SERVICE BULLETIN Customer Support
ATA SYSTEM: 3011 NUMBER: 84 ---30 ---14 

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

SUBJECT: Ice & Rain Protection --- Installation of Timer Monitor Unit P/N 4100S018 ---07 --- ModSum 4 ---126525

1. PLANNING INFORMA TION A. Effectivity Aircraft Affected: In ---Service: DHC ---8 Aircraft Models 401 and 402 Serial Numbers 4001, 4003 ---4004, 4006, 4008 ---4375 with a AERAZUR Timer and Monitor Unit (TMU) p/n 4100S018 ---06 installed. Production: ModSum 4 ---126525 will be installed before delivery on applicable DHC ---8 Aircraft at Serial Number 4376 and subsequent.

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S.B. 84 ---30 ---14 Page 2 of 18 20 May 2011 LS 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.
Part Number Description 4100S018 ---06 AERAZUR Timer and Monitor Unit B. Reason Problem: Multiple in service incidents such as air turn backs and aborted take ---offs have occurred due to the poor reliability of existing Timer Monitor Unit p/n 4100S018 ---06. Failure of the TMU could cause the AUTO deicing mode to become unavailable. Cause: An investigation by the vendor of the TMU has determined that some tantalum capacitors installed in the Module 300 power supply may leak if overstressed. If leakage occurs at any tantalum capacitors site the adjacent PCB insulation weakens. As a result a short ---circuit between GND and the Dual Distributing Valve may occur. Solution: This service bulletin introduces ModSum 4 ---126525. The ModSum replaces the existing TMU p/n 4100S018 ---06 with TMU p/n 4100S018 ---07. The new TMU is redesigned to minimize some of the issues inherent to some of the earlier TMU’s p/n 4100S018 ---06. For additional information refer to the enclosed vendor service bulletin (VSB) AERAZUR 4100S018 ---30 ---001 para 1. PLANNING INFORMATION, D. Description, subpara (3).

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S.B. 84 ---30 ---14 Page 3 of 18 20 May 2011 LS C. Description The procedures in this service bulletin give the instructions to do the tasks that follow: --- the aircraft electrical system is de ---energized --- lock pins are installed thru each main gear and main gear door mechanism --- the nose gear ground lock is engaged --- the lower wardrobe outboard access panel is removed --- existing TMU p/n 4100S018 ---06 is located and removed to agree with AMM procedures --- new TMU p/n 4100S018 ---07 is installed and tested to agree with AMM procedures --- the lower wardrobe outboard access panel is installed --- Close ---Out. D. Compliance Bombardier Inc. recommends incorporation of ModSum 4 ---126525 at the earliest opportunity unless otherwise directed by the operator’s airworthiness authority. An Airworthiness Directive to be issued by Transport Canada 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. This Service Bulletin does not affect Airworthiness Limitations (AWLs) or Damage Tolerance Inspections (DTIs). F. Manpower It will take an estimated 1.5 man ---hours to complete this service bulletin. The breakdown of the man ---hours is shown in the table that follows:

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S.B. 84 ---30 ---14 Page 4 of 18 20 May 2011 LS TASK MAN ---HOURS Job Set ---Up 0.25 Procedure 1.00 Close ---Out 0.25 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 Refer to enclosed AERAZUR VSB 4100S018 ---30 ---001 para 2. MATERIAL INFORMATION section. 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 The initial issue of this service bulletin was prepared to the engineering drawings and related data that follows: ModSum 4 --- 126525 Rev. ‘B’ ModSum 4Q126525 Rev. ‘B’

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S.B. 84 ---30 ---14 Page 5 of 18 20 May 2011 LS AERAZUR VSB 4100S018 ---30 ---001 Issue 0 PCA 43360 Revision 2 (for internal reference only) 2. MATERIAL INFORMA TION A. Parts Required Per Aircraft Refer to applicable information in enclosed AERAZUR VSB 4100S018 ---30 ---001 para 2. MATERIAL INFORMATION section. B. Parts Required to Modify Spares None C. Special Tools and Equipment Required None D. Existing Parts Accountability Refer to applicable information in enclosed AERAZUR VSB 4100S018 ---30 ---001 para 2. MATERIAL INFORMATION section.

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S.B. 84 ---30 ---14 Page 6 of 18 20 May 2011 LS 3. ACCOMPLISHMENTINSTRUCTIONS 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. (3) Make sure the nose gear ground lock is engaged. (4) Gain access to the TMU located behind the wardrobe enclosure. B. Procedure (1) Remove existing TMU p/n 4100S018 ---06 (refer to AMM TASK 30 ---11 ---01 ---000 ---801). (2) Install new TMU p/n 4100S018 ---07 and do applicable return to service checks (refer to AMM TASK 30 ---11 ---01 ---400 ---801). 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.

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S.B. 84 ---30 ---14 Page 18 of 18 20 May 2011 LS 1Jan 2009 SERVICE BULLETIN (SB) --- RECORD OF INCORPORATION --- Q SERIES DASH 8 AIRCRAFT To: CMDB Focal 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