SERVICE BULLETIN - Wing X Stol

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SERVICE BULLETIN Number SB-1-96 April 11, 1996 SUBJECT : Lower Main Spar Cap at Wing Station 100.00 * Inspection and reinforcement, of the lower wing spar cap at the wing lift strut pick-up point at Station 100.00 1. PLANNING INFORMATION A. Effectivity * All Cessna 180 and 182 series aircraft with authorised gross weights in excess of 3,000 Lbs. equipped with A.R.T. “WingExtensions” approved under STA SA93-136 or STC SA00276NY. * All Cessna 185 series aircraft equipped with A.R.T. “WingExtensions” approved under STA SA93-136 or STC SA00276NY. B. Reason Early model wings on the affected aircraft do not incorporate an angle stiffener at the spar splice at wing station 100.00. Static testing performed by A.R.T. has shown that these modified wings do not satisfy the applicable design requirements. The modification introduced by this Bulletin corrects this deficiency. C. Description This Bulletin consists of two parts. Part A consists of an inspection of the area along the lower main spar cap from Station 90 outboard to Station 110, in order to determine if the “angle stiffener ” is present on the subject wing. If the “angle stiffener ” is installed, no further action is required. Part B consists of installation of a reinforcing strap. If the “angle stiffener ” is not present Part B must be accomplished. D. Compliance A.R.T. considers compliance with this Bulletin to be mandatory. E. Approval The design content conveyed by this service bulletin has been approved by a Design Approval Representative for Transport Canada. F. Manpower Approximately 8 man-hours will be required to accomplish this modification. This estimate is for direct labor performed by an experienced crew and it does not include set-up, planning, familiarization, cure time, part fabrication, tool acquisition or lost time. G. Material - Price and Availability A kit consisting of two(2) Stainless Straps (16” L. X 1” W . X 0.077” ) Type and specification : MIL-S-5059 AMS- 5518 H 301 1/2 HARD is available from Air Research Technology. Kits may be obtained by submitting a purchase order, specifying S/N# of WingExtension kit to A.R.T. Administration. H. Weight and Balance Weight Change due to accomplishment of Part B is negligible. ACCOMPLISHMENT INSTRUCTIONS 1. Parts Required Per Aircraft 1. Service Bulletin Kit SB-1-96, consisting of: Part Number Qty Description S S - 1 2 - 1 - 0 7 7 2 Stainless Steel Strap 2. The following materials are required for the completion of this service bulletin and are to be procured by the operator directly from industry sources. Part Number Qty Description CR3213-6-6 28 Universal Head CherryMAX Rivet CR3213-6-7 2 Universal Head CherryMAX Rivet Epoxy Primer INSTRUCTIONS PART A - Inspection 1) Open the inspection hole situated on the underside of the wing, aft of the spar, closest to where the strut connects to the wing. Using a flashlight and a mirror, by visual inspection, ascertain if the subject wing has the “angle stiffener” installed along the lower spar cap between Wing Station 90 and 110 (approximately). Refer to Figures 1 and 2 to assist identification of the “angle stiffener”. 2) Both wings, left and right must be inspected individually. 3 ) The installation of the Stainless Steel Strap 0.077” in accordance with Part B of this Bulletin is MANDATORY on wings which do not incorporate the “angle stiffener”. 4) If the “angle stiffener” is present, do not install S/S straps. Make a log entry indicating that “ART Service Bulletin SB-1-96 Part A complied with, Part B is not applicable due to presence of angle stiffener in both wings”. PART B - Strap Installation 1 ) Installation may only be carried out in an approved sheet metal shop using recognized procedures and techniques. Workmanship must comply with AC43.13-1A. 2) On the underside of the wing, along the spar identify and mark the center of the rib at Wing Station 100.50 using a felt marker . NOTE: Wing Station 100.50 is established by the outboard Web of the center rib at Wing Station 100.00 3 ) To provide room for installing the strap the strut must be removed at the wing junction. Cradle the wing securely and remove the strut connection where it joins to the main spar. 4) Carefully drill out and remove all existing rivets approximately. 8” inboard and 8” outboard of Wing Station 100.50. Caution do not to enlarge the drill holes beyond tolerance or severe spar damage may occur. 5 ) Take the 16” Stainless Steel Strap 0.077” and precisely mark the center using a felt marker. 6) Slide the “s/s strap”under the leading edge wing skins and up against the underwing skin along the spar channel and then center the “s/s strap” at Wing Station 100.50. 7) The “s/s strap” , when centered on Wing Station 100.50 at the spar channel splice will be completely hidden, because it is covered by the leading edge wing skins. When the correct position is established, accurately mark the drill hole positions on the “s/s strap”, the existing L/E wing skin holes can be used as a guide. Then remove the “s/s strap”. IMPORTANT NOTE A) The number of holes to be drilled may vary with different aircraft however (7) rivets on each side of the spar splice at Wing Station 1 0 0 . 5 0 i s t h e m i n i m u m r e q u i r e d i n o r d e r t o o b t a i n t h e d e s i r e d structural strength of the spar splice. B) The hole positions, as marked may not align perfectly down the center of your “s/s strap”. This is normal; however, a rivet edge distance of .375” must be maintained on the “s/s strap”. CAUTION Care must be taken while drilling in order to avoid contact with the strut attach fitting inside the wing. DO NOT SUBSTITUTE the universal head CherryMAX rivets or the Stainless Steel Strap. These parts are shear strength specific and critical to maintaining adequate strength in the wing spar splice. USE ONLY fasteners and materials supplied or referenced herein. If a stainless steel strap is damaged during installation, obtain a new strap from the manufacturer.