Instrument landing of aircraft

NOT many years ago, unfavorable weather conditions meant the cancellation of all aircraft flights. Subsequent development of radio aids to air navigation have made it possible for an airplane to fly with safety under conditions of poor visibility, but it still is necessary to cancel flights where conditions at the airport of destination are such that the pilot cannot see to land. The problem of landing an airplane under adverse weather conditions remains the most important problem in commercial flying today. The United States Civil Aeronautics Authority (now Civil Aeronautics Administration), realizing this to be the bottleneck of safe flying under conditions of low ceiling and poor visibility, has endeavored to overcome the difficulty by fostering the development of a suitable instrument landing system.