The Beechcraft King Air series has its roots in the Twin Bonanza of 1951. That aircraft model was enlarged and re-engined to become the model 65 Queen Air. The Queen Air design changed with a swept tail and pressurization. With the addition of Pratt & Whitney turboprop engines, the Queen Air became the model 90 King Air. The Model 90’s have seen their way through the alphabet with the 90, A90, B90, C90, D90 (not built), E90, F90 and H90 (also not built). The C90 models were the most popular. The model 90 was first certificated in 1959 and is still being produced over four decades later as the C90B and C90SE. Two Pratt & Whitney PT6A-21 engines power all of the C90’s (C90, -1, A, B, SE). As the C90 has progressed, there have been evolutionary changes made in avionics and systems, to keep the aircraft fresh. The C90SE is a “Special Edition” C90 with fewer options, more basic avionics and a reduced base price over the C90B essentially a price leader. The King Air 90’s seat five and have aft-lavatories, a nice feature in a small turboprop. The cabin is not round, but shaped similar to a loaf of bread. This gives the passenger more shoulder room over a round cabin.