# Viking Air Service Bulletin V6/0044: Revision B - Rights: © Viking Air. Filed by the FAA in regulations.gov docket FAA-2022-0007; AD 2022-07-14 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Viking Air Service Bulletin V6/0044](https://openairdocs.org/service-documents/viking/v6-0044.md) - Title as filed: Viking DHC-6 Twin Otter SB V60044 Rev B - Pages: 10 - PDF: https://openairdocs.org/files/sha256/90/ab/90ab3ede4fcd50531f64ad8a779f8a65ace8e90f338250bc584a29d987d31342 - Page: https://openairdocs.org/service-documents/viking/v6-0044/file/90ab3ede4fcd ## Text Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 1959 de Havilland Way Sidney, B.C. Canada V8L 5V5 Tel: (250) 656 - 7227 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 1 of 10   DHC-6 Twin Otter SERVICE BULLETIN ATA SYSTEM: 51-00 NUMBER: V6/0044    I. PLANNING INFORMATION A. Effectivity Aircraft Affected: DHC-6 Series 400 Serial Numbers 845 to 957 operating on floats. B. Reason Corrosion has been reported affecting components in the fuel gallery area on 400 Series Twin Otter aircraft operating on floats. C. Description This Service Bulletin is issued to establish a compliance threshold to incorporate multiple design improvements in the fuel gallery, also to remind operators to follow all applicable maintenance and inspection tasks in Part 2 of PSM 1-6-7 (Special Inspection Requirements), as well as the Basic Inspection Requirements in Part 1 of PSM 1-6-7. D. Compliance NOTE 1: If Revision 'A' of Service Bulletin No. V6/0044 has already been accomplished, no additional action is necessary. NOTE 2: Reminder that it is important to follow all inspection requirements in PSM 1-6-7 Sections SP3.D., SP2.B.2, and SP1.E. or SP1.I. as applicable, as well as the Basic Inspection Requirements in Part 1 of PSM 1-6-7, for the repeat inspections, maintenance, and daily rinsing. NOTE 3: Incorporation of an approved superseding part number or MOD number is acceptable and does not void compliance with this Service Bulletin. Compliance contains 5 requirements: 1. If either MOD 6/2267 or MOD 6/2299 are not incorporated, within twelve (12) months from the issue date of this Service Bulletin, operators shall incorporate either MOD 6/2267 in accordance with Technical Bulletin No. V6/00034 (Fuel Boost Pump EMI Filter Relocation), OR MOD 6/2299 in accordance with Technical Bulletin No. V6/00084 (Introduction of Improved Fuel Boost Pump). NOTE 1: MOD 6/2267 cut-in at production on aircraft S/N 897 MOD 6/2299 cut-in at production on aircraft S/N 950 (replaces MOD 6/2267)    SUBJECT: FUEL GALLERY CORROSION CONTROL ### Page 2 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 2 of 10 NOTE 2: For MOD 6/2267 only, removal of sealant, inspection for corrosion, cleaning, and re-application of sealant is required every 1000 hours, in accordance with PSM 1-6-7 SP3.D., Item 15.a.(2). 2. If MOD 6/2389 is not incorporated, within twelve (12) months  from the issue date of this Service Bulletin, operators shall incorporate MOD 6/2389 in accordance with Technical Bulletin No. V6/00099 (Fuel System Manifold (Tube and Clamp) Electrical Bonding). NOTE : MOD 6/2389 cut-in at production on aircraft S/N 958 3. If MOD 6/2393 is not incorporated, within twelve (12) months  from the issue date of this Service Bulletin, operators shall incorporate MOD 6/2393 in accordance with Technical Bulletin No. V6/00100 (Improved Fuel Drain Valve). NOTE : MOD 6/2393 cut-in at production on aircraft S/N 957 4. If MOD 6/2390 is not incorporated, within twelve (12) months  from the issue date of this Service Bulletin, operators shall incorporate MOD 6/2390 in accordance with Technical Bulletin No. V6/00094 (Improved Fuel Probe Mating Electrical Connection). NOTE : MOD 6/2390 cut-in at production on aircraft S/N 950 5. If either Technical Bulletin No. V6/00124 (retrofit to MOD 6/2006 configuration), MOD 6/2275, MOD 6/2327, or MOD 6/2464 have not been incorporated, brush apply sealant on fuel pressure switch electrical terminals (initial application only) in accordance with Section II.E of this Service Bulletin. OR incorporate MOD 6/2464 in accordance with Technical Bulletin No. V6/00152 (MOD 6/2464 Fuel Pressure Switch Replacement), within twelve (12) months or 1000 flight hours from the issue date of this Service Bulletin, whichever comes first. NOTE 1: Reminder that Pre MOD 6/2327 and TB V6/00124 (MOD 6/2006 retrofit) require repetitive removal of sealant, inspection for corrosion, cleaning, and re-application of sealant to be done every 1000 hours as per PSM 1-6-7 SP3.D., Item 15.a.(2). NOTE 2: MOD 6/2327 cut-in at production on aircraft S/N 936 (Optional as retrofit in accordance with Technical Bulletin No. V6/00074). NOTE 3: MOD 6/2464 replaces MOD 6/2327. (Optional as retrofit in accordance with Technical Bulletin No. V6/00152) MOD 6/2327 is discontinued and is no longer procurable. MOD 6/2327 is a valid means of compliance if it is already installed. NOTE 4: MOD 6/2006 retrofit and sealing of electrical terminals (initial application) in accordance with Technical Bulletin No. V6/00124 is a valid means of compliance if it is already installed. Modkit C6MK2006-1 is discontinued and is no longer procurable. TB V6/00124 retrofit of fuel pressure switches to C6PF1166-5 superseded by MOD 6/2464. ### Page 3 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 3 of 10 E. Approval The technical content of this Service Bulletin has been approved under the authority of Transport Canada Civil Aviation (TCCA) Design Approval Organization (DAO) 04-V-02. F. Labour Requirements Refer to the applicable Technical Bulletins. G. Weight and Balance Refer to the applicable Technical Bulletins. H. Electrical Load Data Refer to the applicable Technical Bulletins. I. Publications Affected Refer to the applicable Technical Bulletins. J. References PSM 1-64-2 Maintenance Manual, Series 400 PSM 1-6-7 Inspection Requirements Manual This Service Bulletin is supported by the following Technical Bulletins: TB V6/00034 Fuel Boost Pump EMI Filter Relocation TB V6/00084 Introduction of Improved Fuel Boost Pump TB V6/00099 Fuel System Manifold (Tube and Clamp) Electrical B onding TB V6/00100 Improved Fuel Drain Valve TB V6/00094 Improved Fuel Probe Mating Electrical Connection TB V6/00074 MOD 6/2327 Fuel Pressure Switch Replacement (Superseded by TB V6/00152) TB V6/00124 Retrofit the Fuel Pressure Switch to C6PF1166-5 (Superseded by TB V6/00152) TB V6/00152 MOD 6/2464 Fuel Pressure Switch Replacement (Supersedes both TB V6/00074 and TB V6/00124) For more information please contact: Viking Air Limited FAX: 403-295-8888 Technical Support Telephone Numbers: 7757 8th Street NE Regional: 587-430-0572 Calgary, Alberta North America: 1-800-663-8444 Canada, T2E 8A2 dh_technical.support@vikingair.com ### Page 4 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 4 of 10 II. ACCOMPLISHMENT INSTRUCTIONS A. PART 1 OF 5 – Required for Aircraft S/N 845 thru 896 OPTION A: MOD 6/2267 (Applicable to Aircraft S/N 845 thru 896) 1. Incorporate MOD 6/2267 in accordance with Technical Bulletin No. V6/00034 (Fuel Boost Pump EMI Filter Relocation), unless previously installed as retrofit. 2. Every 1000 hours, remove all sealant, inspect for corrosion, clean, and re-apply sealant, in accordance with PSM 1-6-7 SP3.D., Item 15.a.(2). OPTION B: MOD 6/2299 (Applicable to Aircraft S/N 845 thru 949) Incorporate MOD 6/2299 in accordance with Technical Bulletin No. V6/00084 (Introduction of Improved Fuel Boost Pump), unless previously installed as retrofit. NOTE 1: MOD 6/2299 is optional for aircraft S/N 897 thru 949 (Post MOD 6/2267). Incorporation is at the discretion of the operator. NOTE 2: MOD 6/2299 is optional for aircraft S/N 845 thru 896 that have previously installed MOD 6/2267 as a retrofit. Incorporation is at the discretion of the operator. NOTE 3: Removal of MOD 6/2267 (if installed) is required to install MOD 6/2299 B. PART 2 OF 5 – Required for Aircraft S/N 845 thru 957 Incorporate MOD 6/2389 in accordance with Technical Bulletin No. V6/00099 (Fuel System Manifold (Tube and Clamp) Electrical Bonding), unless previously installed as retrofit. C. PART 3 OF 5 – Required for Aircraft S/N 845 thru 956 Incorporate MOD 6/2393 in accordance with Technical Bulletin No. V6/00100 (Improved Fuel Drain Valve), unless previously installed as retrofit. D. PART 4 OF 5 – Required for Aircraft S/N 845 thru 949 Incorporate MOD 6/2390 in accordance with Technical Bulletin No. V6/00094 (Improved Fuel Probe Mating Electrical Connection), unless previously installed as retrofit. E. PART 5 OF 5 – Required fo r Aircraft S/N 845 thru 935 OPTION A: Sealing Fuel Pressure Swit ch Terminals and Repeat Applications If sealing of the fuel pressure switch electrical terminals was not incorporated as part of MOD 6/2275 in accordance with Technical Bulletin No. V6/00033, do the following: 1. Remove and discard connector covers at fuel pressure switch electrical terminals. 2. Prepare PRC P/S 870 Class A sealant in accordance with manufacturer’s instructions. Use brush to apply dome seal to fuel pressure switch electrical terminals in accordance with standard practices. 3. Every 1000 hours, remove all sealant, inspect for corrosion, clean, and re-apply sealant, in accordance with PSM 1-6-7 SP3.D., Item 15.a.(2). ### Page 5 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 5 of 10 OPTION B: MOD 6/2327 MOD 6/2327 (Technical Bulletin No. V6/00074) is a valid means of compliance if it has already been installed. NOTE: MOD 6/2327 is discontinued and is no longer procurable. MOD 6/2327 is superseded by MOD 6/2464 (TB V6/00152). OPTION C: Retrofit to Pre MOD 6/2327 Configuration (MOD 6/2006 Retrofit IAW TB V6/00124) 1. Retrofit to MOD 6/2006 configuration and sealing electrical terminals in accordance with Technical Bulletin No. V6/00124 (Retrofit the Fuel Pressure Switch to C6PF1166-5) is a valid means of compliance (initial sealant application only) if it has already been accomplished. NOTE: Retrofit Modkit C6MK2006-1 is discontinued and is no longer procurable. Technical Bulletin No. V6/00124 is superseded by Technical Bulletin No. V6/00152 (MOD 6/2464) 2. Every 1000 hours, remove all sealant, inspect for corrosion, clean, and re-apply sealant, in accordance with PSM 1-6-7 SP3.D., Item 15.a.(2). OPTION D: MOD 6/2464 Incorporate MOD 6/2464 in accordance with Technical Bulletin No. V6/00152 (MOD 6/2464 Fuel Pressure Switch Replacement), unless previously installed as retrofit. ### Page 6 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 6 of 10 F. RECORDING 1. After completion of Part 1 of this Service Bulletin, make the following entries in the aircraft log as applicable: OPTION A (MOD 6/2267) a) As required by Technical Bulletin No. V6/00034. b) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 1, Option A, has been completed in accordance with Section II.A. (initial sealant application only)” OPTION B (MOD 6/2299) a) As required by Technical Bulletin No. V6/00084. b) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 1, Option B, has been completed in accordance with Section II.A.” OR: “MOD 6/2267 previously incorporated. Part 1 of Service Bulletin No. V6/0044 Revision B is not applicable.” OR: “MOD 6/2299 previously incorporated. Part 1 of Service Bulletin No. V6/0044 Revision B is not applicable.” 2. After completion of Part 2 of this Service Bulletin, make the following entries in the aircraft log: a) As required by Technical Bulletin No. V6/00099. b) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 2, has been completed in accordance with Section II.B.” OR: “MOD 6/2389 previously incorporated. Part 2 of Service Bulletin No. V6/0044 Revision B is not applicable.” 3. After completion of Part 3 of this Service Bulletin, make the following entries in the aircraft log: a) As required by Technical Bulletin No. V6/00100. b) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 3, has been completed in accordance with Section II.C.” OR: “MOD 6/2393 previously incorporated. Part 3 of Service Bulletin No. V6/0044 Revision B is not applicable.” 4. After completion of Part 4 of this Service Bulletin, make the following entries in the aircraft log: a) As required by Technical Bulletin No. V6/00094. b) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 4, has been completed in accordance with Section II.D.” OR: “MOD 6/2390 previously incorporated. Part 4 of Service Bulletin No. V6/0044 Revision B is not applicable.” ### Page 7 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 7 of 10 5. After completion of Part 5 of this Service Bulletin, make the following entry in the aircraft log as applicable: OPTION A (Sealing Fuel Pressure Switch Terminals – Initial Application) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 5, Option A has been completed in accordance with Section II.E. (initial application only).” OR: “MOD 6/2275 previously incorporated. Part 5 of Service Bulletin No. V6/0044 Revision B is not applicable (initial sealant application only).” OPTION B (MOD 6/2327) “MOD 6/2327 previously incorporated. Part 5 of Service Bulletin No. V6/0044 Revision B is not applicable.” OPTION C (Technical Bulletin No. V6/00124) “Technical Bulletin No. V6/00124 previously accomplished. Part 5 of Service Bulletin No. V6/0044 Revision B is not applicable (initial sealant application only).” OPTION D (MOD 6/2464) a) The required entry in the aircraft log as required by Technical Bulletin No. V6/00152. b) “Service Bulletin No. V6/0044 Revision B – Fuel Gallery Corrosion Control – Part 5, Option D, has been completed in accordance with Section II.E.” OR: “MOD 6/2464 previously incorporated. Part 5 of Service Bulletin No. V6/0044 Revision B is not applicable.” 6. Complete attached Operator Reply Form on Page 9 and return to Viking Air Technical Support. III. MATERIAL INFORMATION AND TOOLING A. Material Information (Par ts Required Per Aircraft) 1) Refer to the applicable Technical Bulletins 2) PRC P/S 870 Class A sealant (if required by Part 5, Options A and C) B. Tooling – Price and Availability Refer to the applicable Technical Bulletins. ### Page 8 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 8 of 10 THIS PAGE INTENTIONALLY LEFT BLANK ### Page 9 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 9 of 10 Service Bulletin V6/0044 Revision B – Operator Reply Form Operator: Contact Person: Contact Phone/Email: A/C Registration # A/C Serial # A/C TTSN A/C TCSN Part 1 (Section II.A) MOD 6/2267 previously incorporated? YES / NO Date Incorporated MOD 6/2299 previously incorporated? YES / NO Date Incorporated Option A (MOD 6/2267 IAW Technical Bulletin No. V6/00034) incorporated? YES/NO Date: Option B (MOD 6/2299 IAW Technical Bulletin No. V6/00084) incorporated? YES/NO Date: Part 2 (Section II.B) MOD 6/2389 previously incorporated? YES / NO Date Incorporated Date of Incorporation of Technical Bulletin No. V6/00099 (MOD 6/2389): Part 3 (Section II.C) MOD 6/2393 previously incorporated? YES / NO Date Incorporated Date of Incorporation of Technical Bulletin No. V6/00100 (MOD 6/2393): Part 4 (Section II.D) MOD 6/2390 previously incorporated? YES / NO Date Incorporated Date of Incorporation of Technical Bulletin No. V6/00094 (MOD 6/2390): Part 5 (Section II.E) MOD 6/2275 previously incorporated? YES / NO Date Incorporated MOD 6/2327 previously incorporated? YES / NO Date Incorporated TBV6/00124 previously retrofit (MOD 6/2006)? YES / NO Date Incorporated MOD 6/2464 previously incorporated? YES / NO Date Incorporated Option A (Sealing Fuel Pressure Switch Terminals) incorporated? YES / NO / N/A Date: Option D (MOD 6/2464 IAW Technical Bulletin No. V6/00152) incorporated? YES/NO Date: Additional Comments: Please return form via email to dh_technical.support@vikingair.com or via fax to 403-295-8888 ### Page 10 SERVICE BULLETIN V6/0044 13-Sep-2021 S.B. V6/0044 Revision ‘B’ Page 10 of 10 THIS PAGE INTENTIONALLY LEFT BLANK --- 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.