# Viking Air Service Bulletin V3/0002: Revision C - Rights: © Viking Air. Filed by the FAA in regulations.gov docket FAA-2015-3073; AD 2015-24-02 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Viking Air Service Bulletin V3/0002](https://openairdocs.org/service-documents/viking/v3-0002.md) - Title as filed: U.S. DOT/FAA - SB V3-0002 RevC - COMPLETE-Distributed copy - Pages: 14 - PDF: https://openairdocs.org/files/sha256/31/a6/31a63b4dd404ea34727ad9611448d7484c3f1c4b072511c8be93bfdf46e06fa7 - Page: https://openairdocs.org/service-documents/viking/v3-0002/file/31a63b4dd404 ## Text Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 SERVICE BULLETIN TRANSMITTAL SHEET Service Bulletin No.: V3/0002 Date of Original Issue: 22-September-2010 Revision No.: Revision C Date of Issue: 30-April-2014 DHC-3 COMPLETE WING BOX INSPECTION – BORESCOPE AND VISUAL Viking has received SDRs related to cracking of the DHC- 3 wing upper skin corrugations as well as cracks in the m ain spar lower cap. The intent of this S ervice Bulletin is to detect and repair these cracks and to obtain as much information as possible from operators to evaluate the overall condition of the fleet to assess if further action is required. NOTE 1: NO RETROACTIVE THRESHOLD INSPECTION IS REQUIRED IF THRESHOLD INSPECTION FROM SB V3/0002 REVISION A OR B HAS BEEN COMPLETED – CONTINUE WITH REPEAT INSPECTIONS IN ACCORDANCE WITH SB V3/0002 REVISION C AT APPROPRIATE REPEAT INSPECTION SCHEDULE. NOTE 2: ALL OTHER AIRCRAFT MUST INCORPORATE APPLICABLE INSPECTIONS IN ACCORDANCE WITH SB V3/0002 REVISION C. NOTE 3: This revision supersedes the previous revision of this Service Bulletin. NOTE 4: Revision bars in the left margin of this Service Bulletin denote changes from the previous revision. This page transmits Revision ‘C’ of Service Bulletin V3/0002, pages 1 thru 12, dated 30 April 2014. Service Bulletin re-issued to include incorporation of MOD 3/1005 (MOD for inspection access holes) and detailed compliance and accomplishment instructions for the inspection of the entire wing box assembly. Remove Service Bulletin V3/0002 Revision ‘B’ dated 03 July 2013 and replace with attached. Previous issues of Service Bulletin V3/0002: Initial Issue – (22-Sep-2010) - effectivity – All DHC-3 aircraft Revision A – (22-Feb-2013) - effectivity – All DHC-3 aircraft Revision B – (03-Jul-2013) - effectivity - All DHC-3 aircraft Page 1 of 2 ATA Ref: 57-00 30-April-2014 Service Bulletin V3/0002 ### Page 2 THIS PAGE INTENTIONALLY LEFT BLANK Page 2 of 2 ATA Ref: 57-00 30-April-2014 Service Bulletin V3/0002 ### Page 3 1959 De Havilland Way Sidney, B.C. Canada V8L 5V5 Tel: (250) 656 - 7227 SERVICE BULLETIN ATA SYSTEM: 5700 NUMBER: V3/0002 SUBJECT: DHC-3 Complete Wing Box Inspection – Borescope and Visual I. PLANNING INFORMATION A. Effectivity The complete wing box inspection requirement laid out herein, has an effectivity of ALL DHC-3 aircraft. NOTES: To perform this inspection, improved access is required. Refer to Section II.A. of this Service Bulletin for details. Before you do this Service Bulletin, read ALL Sections of the bulletin and examine all Supplemental Type Certificate (STC) or equivalent action changes to make sure this Service Bulletin can be completed. FOR AIRCRAFT EQUIPED WITH STCs or EQUIVALENT CHANGES, THE OPERATOR MUST CONTACT THE STC HOLDER TO EVALUATE CONFLICT POSSIBILITIES. B. Reason Viking has received Service Difficulty Reports (SDR’s) related to cracking of the DHC-3 wing upper skin corrugations as well as cracks in the main spar lower cap. The intent of this Service Bulletin is to detect and repair these cracks and to obtain as much information as possible from operators to evaluate the overall condition of the fleet and assess if further action is required. All wings require internal inspections in order to maintain long term structural integrity. The purpose of incorporating additional inspection openings is to provide sufficient access to complete a thorough inspection of the DHC-3 wing. C. Description Inspections are required to identify possible cracking, corrosion or any other damage of the wing box assembly. To accommodate these inspections, access panels are incorporated in the wing lower skin in accordance with MOD 3/1005 ( MOD Kit DWG C3MK1005; MOD Kit C3MK1005-1). DHC-3 OTTER 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 1 of 12 ### Page 4 SERVICE BULLETIN V3/0002 The purpose of this Service Bulletin is to: 1. Borescope inspect and visually inspect the wing box for cracks and corrosion. 2. As soon as possible following the first inspection accomplished in accordance with Revision C of the Service Bulletin, complete the Operator Reply Form included with this Service Bulletin even if no cracks or damage is found. 3. Repair damage prior to next flight. D. Compliance The compliance time for actions associated with this Service Bulletin is listed in Table 1 below. NOTE 1: To accomplish inspection (action) from Table 1 below, incorporate lower wing skin access openings as defined in Section II.A. of this Service Bulletin. NOTE 2: If actual flight hours of wing are not known, contact Technical Support at Viking Air Limited (see Sec. I.J for contact information) to assist in the determination. NOTE 3: If SB V3/0002 Rev A or B has been complied with prior to the issue date of SB V3/0002 Rev C, continue with the repeat inspections, in accordance with Table 1 below, from the last completed inspection in accordance with SB V3/0002 Rev A or B. NOTE 4: Damage shall be repaired prior to next flight in accordance with accepted data (such as PSM1-3-3) or other approved data. TABLE 1 – WING BOX INSPECTION - COMPLIANCE DETAILS Action Action Detail Effectivity Threshold Inspection Repeat Inspection Complete wing box inspection Do a borescope and visual inspection on ALL areas of the Wing Box in accordance with (Sec. II). a. <31,200 wing flight hours Within 800 wing flight hours or within 6 months of issue date of this SB (whichever occurs first) Also see note 3 Every 1600 wing flight hours or 2100 flight cycles (whichever occurs first) b. 31,200≤ wing flight hours <31,600 Before accumulating 32,000 wing flight hours or within 6 months of issue date of this SB (whichever occurs first) c. ≥ 31,600 wing flight hours Within 400 wing flight hours or 3 months of the issue date of this SB (whichever occurs first) 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. 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 2 of 12 ### Page 5 SERVICE BULLETIN V3/0002 F. Manpower An estimated 36 man-hours per wing will be required to complete this Service Bulletin (16 man hours to install access panels and 20 hours to inspect the wing components). All costs to complete the inspection of the wing components are the responsibility of the Operator. G. Weight and Balance FOR MOD 3/1005 (Current) FOR MOD 3/1002 (Original) AIRCRAFT STATION WEIGHT AIRCRAFT STATION WEIGHT STA 139.25 +1.58 lbs STA 134.15 +1.58 lbs STA 159.63 +0.60 lbs STA 159.63 +0.60 lbs H. Electrical Load Data Not affected. I. Publications Affected None. J. References This Service Bulletin contains a Survey to be completed and returned to Viking. The following drawings have been provided with this Service Bulletin to illustrate the technical activities: C3MK1005, C3Z1001, and C3Z1002. For more information please contact: Viking Air Limited Technical Support 1959 De Havilland Way Sidney, British Columbia V8L 5V5 technical.support@vikingair.com FAX: 250-656-0673 Telephone Numbers: Regional: 250-656-7227 North America: 1-800-663-8444 International: 1-800-6727-6727 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 3 of 12 ### Page 6 SERVICE BULLETIN V3/0002 II. ACCOMPLISHMENT INSTRUCTIONS A. INTRODUCTION OF NEW ACCESS HOLES IN THE LOWER WING SKIN 1. To perform this inspection, Viking is providing MOD 3/1005 (MOD KIT DWG C3MK1005) for the incorporation of access holes which is only suitable for incorporation on OEM wings used on OEM aircraft. NOTE 1: (a) If MOD 3/1002 (MOD Kit DWG C3MK1002) has been incorporated in accordance with SB V3/0002 Revision A or B, the incorporation of MOD 3/1005 (MOD Kit DWG C3MK1005) is not required in order to accomplish the inspection requirements of this Service Bulletin. (b) If the inspection opening at wing station 53.75 has been incorporated in accordance with SB V3/0002 Revision NC, no change is required at this location, but the remaining inspection openings specified in MOD 3/1005 (MOD Kit DWG C3MK1005) are required unless MOD 3/1002 (MOD Kit DWG C3MK1002) was also incorporated. NOTE 2: MOD 3/1005 (MOD Kit DWG C3MK1005) is compatible for wings fitted with STC SA94-114 (or US STC SA00287NY) STOL Kit. NOTE 3: For aircraft fitted with Viking STC SA03-50, refer to Service Bulletin SB 3-STC(03-50)-001 for applicable access instructions. NOTE 4: For Wings / Aircraft equipped with STCs or equivalent changes, other than mentioned in Section II.A.1. above, the operator must contact the STC holder to evaluate conflict possibilities. 2. Add applicable new access holes in accordance with MOD Kit C3MK1005-1 on both Left Hand (LH) Wing and Right Hand (RH) Wing. 3. Parts can be fabricated by qualified individuals or purchased from Viking Product Support. B. COMPLETE WING BOX INSPECTION The Left Hand (LH) Wing: 1. Remove all inspection access panels / plugs between wing root and wing tip, including those for the access holes incorporated in Section II.A. above, and remove wing tip in accordance with PSM1-3-2 Section 2.15.1. 2. Using a flexible borescope, inspect for cracks, corrosion, missing/smoking/working /broken fasteners or other damage on the entire internal structure of wing between wing root and wing tip, upper/lower skins, ribs (webs, upper/lower flanges), fore and aft surfaces of nose spar, main spar and rear spar (including caps and webs). Pay particular attention to the following areas for cracks in fastener holes and open holes: (a.) Skin splice; (b.) Spar Web splice; (c.) Spar cap splice; 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 4 of 12 ### Page 7 SERVICE BULLETIN V3/0002 (d.) Hinge attachments on rib and rear spar; (e.) Fastener holes on skin (especially those common to the inboard/outboard- end-row of fastener holes on the reinforcement doublers); (f.) Access cutouts and lightening holes on spar/rib webs; (g.) Rib attachment to the webs and caps of the nose spar, main spar, and rear spar, looking for cracks in flanges, bending radii and at fastener heads; (h.) Corrugations at rib attachments (both forward and aft of the main spar). See Figure 1A and 1B for typical corrugation cracks; (i.) All fastener holes on the lower spar caps (main and rear spar), lower stringers and lower skins between wing root and wing tip. Note that fatigue prone areas may be located between Sta 135 and 185. See Figure 1C for example of cracks on main spar lower cap. 3. Carry out a detailed inspection of the exterior surface of the wing for cracks, corrosion, missing/smoking/working/broken fasteners or other damage. Pay particular attention to skin splice, and access cutouts. 4. Do a visual i nspection around doubler area of inspection holes at every repeat inspection. 5. Document all findings and cracks (noting length, direction, wing station position, smoking fasteners, oversized or broken fasteners, etc.); include pictures identifying the location (use station number) and orientation of all findings. 6. Complete the attached Post Inspection Survey Report Form (even if no damage was found) and forward to Technical Support as soon as possible (see Sec. I.J for contact information). 7. Repair damage prior to next flight. NOTE: Repairs shall be in accordance with accepted data such as PSM1-3-3 or other approved data. 8. Re-install inspection panels and wing tip in accordance with PSM1-3-2 Section 2.15.2. The Right Hand (RH) Wing: 9. Repeat Step II.B.1 to Step II.B.8 on the RH wing. D. RECORDING 1. Make an entry in the aircraft flight log book upon completion of access hole incorporation associated with MOD 3/1005: “INCORPORATION OF MOD 3/1005 ACCESS HOLES COMPLETED IN ACCORDANCE WITH SECTION II.A OF SB V3/0002 Revision C AT XX,XXX WING FLIGHT HOURS FOR WING S/N XXX.” 2. Complete Operator Reply Form attached following the first inspection incorporated 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 5 of 12 ### Page 8 SERVICE BULLETIN V3/0002 in accordance with Revision C of Service Bulletin V3/0002, and send it to Viking Air Limited Technical Support. 3. Make an entry in the aircraft flight log book upon completion of Section II.B of this Service Bulletin: “ INSPECTIONS COMPLETED IN ACCORDANCE WITH SECTION II.B OF SB V3/0002 Revision C AT XX,XXX FLIGHT HOURS FOR WING S/N XXX; INSPECTIONS RESULTS SENT TO VIKING AIR LIMITED.” III. MATERIAL INFORMATION AND TOOLING A. Material • Modification Kit C3MK1005-1 (includes MOD Kit DWG C3MK1005 and DWGs C3Z1001 & C3Z1002) B. Tooling – Price and Availability (a) Flexible Borescope Kit with light (b) Flashlight and mirror (c) Wing Support Stand (d) Standard AME hand tools 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 6 of 12 ### Page 9 SERVICE BULLETIN V3/0002 IV. FIGURES AND TABLES FIGURE 1A – TYPICAL CORRUGATION CRACKS FIGURE 1B – CORRUGATION CRACKS ON ONE OF THE WING SDR Typical Corrugation Cracks 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 7 of 12 ### Page 10 SERVICE BULLETIN V3/0002 FIGURE 1C – CRACKS ON MAIN SPAR LOWER CAP FROM ONE OF THE WING INSPECTION SDR 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 8 of 12 ### Page 11 SERVICE BULLETIN V3/0002 Service Bulletin V3/0002 – Operator Reply Form (Left Hand Wing) Operator Name: Contact Person: Contact Phone/Email: A/C Serial Number: Wing S/N: Total Time on Wing (in hrs): Inspection Findings (use Figure 2 diagram below to indicate location of findings): Additional Comments: Please return form via email to technical.support@vikingair.com or via fax to 250-656-0673 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 9 of 12 ### Page 12 SERVICE BULLETIN V3/0002 4 3 2 1 37.15 8 7 6 5 47.5 11 10 9 60 14 13 12 72.5 17 16 15 85 20 19 18 97.5 23 22 21 110 26 25 24 122.5 29 28 27 135 32 31 30 147.5 35 34 33 160 38 37 36 172.5 41 40 39 185 44 43 42 197.5 47 46 45 210 50 49 48 222.5 53 52 51 235 56 55 54 247.5 59 58 57 260 62 61 60 272.5 65 64 63 285 68 67 66 297.5 71 70 69 310 74 73 72 322.5 FIGURE 2 – FINDING LOCATION DIAGRAM 335 Front Spar Main Spar Rear Spar Sta. No. NOT E: NOT TO SCALE – FO R R EF ER ENC E PUR PO SE S ONL Y LEFT HAND WING – LOOKING UP AT TOP SKIN Document all findings and crack locations on this page Noting length, WS position, rivet locations, loose, oversized or blind fasteners, etc. 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 10 of 12 ### Page 13 SERVICE BULLETIN V3/0002 Service Bulletin V3/0002 – Operator Reply Form (Right Hand Wing) Operator Name: Contact Person: Contact Phone/Email: A/C Serial Number: Wing S/N: Total Time on Wing (in hrs): Inspection Findings (use Figure 3 diagram below to indicate location of findings): Additional Comments: Please return form via email to technical.support@vikingair.com or via fax to 250-656-0673 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 11 of 12 ### Page 14 SERVICE BULLETIN V3/0002 1 2 3 4 37.15 5 6 7 8 47.5 9 10 11 60 12 12 14 72.5 15 16 17 85 18 19 20 97.5 21 22 23 110 24 25 26 122.5 27 28 29 135 30 31 32 147.5 33 34 35 160 36 37 38 172.5 39 40 41 185 42 43 44 197.5 45 46 47 210 48 49 50 222.5 51 52 53 235 54 55 56 247.5 57 58 59 260 60 61 62 272.5 63 64 65 285 66 67 68 297.5 69 70 71 310 72 73 74 322.5 FIGURE 3 – FINDING LOCATION DIAGRAM Rear Spar Main Spar Front Spar Sta. No. 335 RIGHT HAND WING – LOOKING UP AT TOP SKIN Document all findings and crack locations on this page Noting length, WS position, rivet locations, loose, oversized or blind fasteners, etc. 30-April-2014 S.B. V3/0002 Revision ‘C’ Page 12 of 12 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. 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