68-15-02 BRITISH AIRCRAFT CORPORATION: Amendment 39-623. Applies to Viscount Models 744, 745D and 810 Series Airplanes.
Compliance required as indicated.
To detect and repair cracks in the elevator root and ribs P/Ns 60920-65, 60920-63, 72420-11 for Models 744 and 745D, and 81020 Shts. 81 and 83 for Model 810, accomplish the following:
(a) For airplanes that have accumulated 7850 or more landings, inspect in accordance with paragraph (c) within the next 150 landings after the effective date of this AD and thereafter at intervals not to exceed 475 landings from the last inspection.
(b) For airplanes that have accumulated less than 7850 landings, inspect in accordance with paragraph (c) prior to the accumulation of 8000 landings and thereafter at intervals not to exceed 475 landings from the last inspection.
(c) Visually inspect the root end ribs for cracks in accordance with British Aircraft Corporation Preliminary Technical Leaflet No. 274 Issue 1 (700 Series)or No. 138 Issue 1 (800/810 Series) or later ARB-approved issues or an FAA-approved equivalent.
(d) If cracks are detected during the inspection specified in paragraph (c), within the next 10 landings incorporate the Repair/ Reinforcement scheme in accordance with British Aircraft Corporation Preliminary Technical Leaflet No. 274 Issue 1 (700 Series) or No. 138 Issue 1 (800/810 Series) or later ARB-approved issues or an equivalent approved by the Chief, Aircraft Certification Staff, FAA, European Region.
(e) If not already accomplished under paragraph (d), within the next 3,000 landings after the effective date of this AD, incorporate the Repair/Reinforcement Scheme in accordance with British Aircraft Corporation Preliminary Technical Leaflet No. 274 Issue 1 (700 Series) or No. 138 Issue 1 (800/810 Series) or later ARB-approved issues or an equivalent approved by the Chief, Aircraft Certification Staff, FAA, European Region.
(f) After incorporation of the Repair/Reinforcement Scheme in accordance with either paragraph (d) or (e), repeat the visual inspection specified in paragraph (c) prior to the next takeoff after each occurrence of severe nosewheel shimmy, or at intervals not to exceed 3,000 landings from the last inspection, whichever occurs earlier.
(g) For the purpose of complying with this AD, subject to acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing each airplane's hours' time in service by the operator's fleet average time from takeoff to landing for the airplane type.
This amendment becomes effective July 23, 1968.