The Model 90s 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 E90 is a C90 with more powerful Pratt & Whitney PT6A-28 engines and a higher gross weight. The E90 was produced from 1974 to 1980. 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.