The FIRST FLIGHT CL-4S, Boeing 1918

The FIRST FLIGHT CL-4S, Boeing 1918

The Boeing CL-4S holds a unique place in the history of civil aviation as the aircraft used for the world's first International Contract Air Mail Service, in this instance between Seattle in the state of Washington, USA, and Victoria in the province of British Columbia, Canada, on March 3, 1919.

Air mail was not new: since February 18, 1911 there had been at least 14 separate air services in eight countries; but the service flown on March 3, 1919 was the first formally constituted international service.

The CL-4S used by Edward Hubbard, with William Boeing as a passenger, was the sole CL45, which Boeing had built as a personal aircraft under the designation C-700 as the aircraft followed on from a batch of 50 Model C (or Model 5) floatplane primary trainers built for the US Navy with the serials C-650 to C-699.

The C-700 was at first identical with the US Navy's Model Cs, but in December 1918 Boeing modified it to accommodate the new 100-hp Hall-Scott L-4 inline in place of the 100-hp Hall-Scott A-7A used in the navy aircraft. The aircraft was in no way distinguished, being a conventional machine by the standards of the day, though it did have the unusual feature of having no fixed tailplane, longitudinal stability being catered for by the relative angles of incidence of the wings, coupled with their heavy stagger.

The elevators were quite small in area.

The flight by Hubbard and Boeing may with some justice be regarded as the first commercial air service in the USA after World "Var I, but though 60 letters were carried, the operation was in reality a survey flight for the definitive service, which began with a number of trials in July 1920 and became a regular operation only on October 15, 1920, thus giving Aeromarine Airways the distinction of being the first US operator to initiate a

regular service after World War 1.

The service operated by Hubbard was part of the mail route to the Far East, Victoria being the terminus for the Japanese ship Africa Maru. The regular service was operated by a B-1 flying boat, which first flew on December 27, 19]9.

As the CL-4S was operating in Canada, it had to carry a registration marking, and in the absence of US markings at that time, it was registered GCADR, the G for Great Britain, and the C for Canada.