Described in a 1964 flight test report by Flight International as the "Rolls-Royce of the propeller-driven fleet", the Beechcraft King Air is that rare product that enters the commercial market ahead of the competition and somehow manages to stay atop through nearly half a century.
Launched by Olive Ann Beech, chairman and president of her eponymous company, the King Air's low-wing cantilever monoplane design almost certainly exceeded even her expectations for success.
In its first 40 years of production, the King Air outsold all its competitors combined. The type is listed in the US National Air and Space Museum's luminous inventory as "the world's most popular turboprop aircraft".
Either by virtue of its own success or the failure of the market to fill a vacuum, the King Air occupies a lucrative space for small and midsize corporate fleets, as well as seemingly insatiable demand as a sensor and transport platform from military and government buyers around the world.
Its grip on the market for a light-twin turboprop is such that it has faced few attempts at head-on competition, with its rivals falling in both the single-engined turboprop and light turbofan categories.
The King Air's success may have been predicted. Beech helped pioneer the market for business aviation with Staggerwing in the 1930s and the best-selling Model 18 Twin Beech that became ubiquitous on civil airfields after the Second World War.
But the King Air proved the most adaptable of the Beech product family. It has survived multiple changes of manufacturing ownership, absorbed design changes that include a T-tail and a trebling of available engine power, and proved serviceable in more business, military and commercial roles than can be listed here.
With its latest technology refresh, the King Air 350ER has enough range to reach Hawaii from California, the longest leg any twin-engined turboprop will ever need to cross. And it again proves the King Air can go further than anyone might expect.
©Cutaway Drawings: Ian Epton