LONDON — Air Marshal Arthur McDonald, a career Royal Air Force officer who conducted a secret rehearsal of the Battle of Britain three years before the Luftwaffe flew into a well-prepared hornet's nest that handed Adolf Hitler his first defeat and changed the course of World War II, has died.
He was 93.
A longtime senior officer whose posts included the last British command of the Pakistani air force, Mr. McDonald, who retired in 1961, was also a noted amateur sailor who represented England in the 1948 Olympics and won his last race at the age of 92.
London newspapers reported he died July 26.
It was in June 1937 that a civilian airliner took off from the Netherlands and flew across the North Sea on a flight of such uneventful routine that when the plane landed safely in London the Dutch pilot had no idea that he had unwittingly become a footnote to military history or that Squadron Leader Arthur McDonald had tracked him all the way.
For, although there had been earlier tests with cooperating RAF target planes, the Dutch airliner was the first foreign plane in history to be detected and tracked by a new system that later became known as radar.
It was a British scientist who discovered and developed radar, but it was Mr. McDonald who led the effort to adopt the technology for military use.
By the time the air assault began as a prelude to a German invasion, the British had a chain of radar beacons and the techniques that Mr. McDonald had designed for the rapid, accurate, and efficient deployment of defending planes.