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 model 90 was first certificated in 1959. The F90 is a C90 with more powerful Pratt & Whitney PT6A-135 engines, a T-tail, B200 wings, and a higher gross weight. The F90/F90-1 was produced from 1979 to 1987. The F90 series is the performance champion of the 90 series. It has more powerful engines than any of the other King Air 90 models. 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.