sentences:  By 1957, Airwork and Hunting-Clan had converted their successful East, West and Southern African "Safari"/colonial coach flights into regular "third-class" scheduled services.However, the Government forced the independents to maintain additional stops that were no longer needed, as a result of replacing Vikings with technologically advanced Douglas DC-6s and Vickers Viscounts.It also required them to share all traffic with BOAC on a 30