70-03-02 BRITISH AIRCRAFT CORPORATION: Amdt. 39-929. Applies to Viscount Models 744, 745D, and 810 series airplanes.
Compliance is required as indicated.
To prevent possible failure of the fuselage pressure shell in the area under the dorsal fin structure, accomplish the following:
(a) Within the next 90 days after the effective date of this airworthiness directive or within eight years after the date of manufacture, whichever occurs later, and thereafter at intervals not to exceed 12 months from the last inspection, visually inspect the fuselage skin under the dorsal fin for corrosion and breakdown of the protective paint. These inspections may be accomplished through the leading edge access panel for the anti-icing duct connection at the base of the fin and through new inspection holes installed in the dorsal fin in accordance with Figures 2 and 3 of the British Aircraft Corporation Preliminary Technical Leaflet No. 278, Issue 1, for Model 744 and 745D airplanes; orPreliminary Technical Leaflet No. 143, Issue 1 for Model 810 airplanes; or an FAA-approved equivalent.
(b) If skin corrosion is found during the inspections required by paragraph (a), before further flight:
(1) Repair the corroded area in accordance with the Viscount Repair Manual, or
2) Remove the complete dorsal fin (segments or all at once), repair the corroded skin, and reseal, and repaint the fuselage skin under the dorsal fin in accordance with the Airframe Corrosion Section of Viscount Overhaul Manual, for Model 744 airplanes; the Instruction Manual, for Model 745D airplanes; the Aircraft Manual, for Model 810 airplanes; or an FAA-approved equivalent.
(c) The repetitive inspections required by paragraph (a) may be discontinued when all segments of the dorsal fin have been removed and the corrective action required by paragraph (b)(2) has been accomplished.
This amendment becomes effective February 22, 1970.