Strangely, the seemingly randomly chosen examples of incidents are, neither, McDonnell-Douglas aircraft. The DC-9series aircraft was first certificated for commercial use in 1965 and has been, along with the Boeing 737 series one of the most successful and dependable aircraft in the world. The Aloha flight referenced brought to light the problem of aging aircraft and from this experience has come new and improved maintenance practices for dealing with high time aircraft. The Air Transat flight revealed an anomaly in the fuel system of the Airbus A-330 caused by chafing of a fuel line on a hydraulic pump. Knowledge gained from both incidents has greatly increased aviation safety. Over 2,500 of these fine aircraft were manufactured with most either still flying or safely retired and residing in the desert.