 His vice-president, Joe Clark, arranged a deal with Morrison-Knudsen and got Raisbeck started on developing the Mark VI system of performance enhancements for the Beech Super King Air.Clark would later go on to co-found Horizon Airlines and Aviation Partners Inc..The Mark VI system included nacelle wing lockers, dual aft body strakes, exhaust stack fairings, engine inlet ram air recovery system, high-flotation landing gear doors and enhanced performance inboard wing leading edge.