Sabena airliners which were augmented and later replaced by Douglas DC-6Bs. The DC-4s also restarted the airline's traditional route to the Belgian Congo. Sabena was the first airline to introduce transatlantic schedules from the north of England, when one of its DC-6Bs inaugurated the Brussels-Manchester-New York route on 28 October 1953. The Convair 240 was introduced in 1949 to partially replace the DC-3s that until then had flown most European services. As of 1956, improved Convair 440 "Metropolitan" twins began replacing the Convair 240 twins and were used successfully well into the 1960s between European regional destinations. In 1957, the long-range
Alcazar (airline) Sabena. In addition, they had a strong tie with Northwest Airlines. In 1989, KLM bought 20 percent of the then ailing airline. In 1992, KLM had made a bailout purchase of Northwest, securing a 25 percent ownership of the airline, which is the maximum a foreign airline is allowed to own in a US airline. Swissair cooperated with Delta Air Lines and Singapore Airlines in a triangular cooperation, which was highly valued by the company's management. Delta was significantly larger than the other two US partner airlines, and had a base in New York City, rather than Northwest's hubs in