When observing the Boeing 757 on the ramp, keen-eyed observers might notice a significant difference in the shape and sound of the powerplants under the wings. This leads to a very interesting question: why does the Boeing 757 have two distinct engine types, the Rolls-Royce RB211 and the Pratt & Whitney PW2000? Engine choice is a primary driver of an aircraft’s performance, fuel efficiency, and maintenance profile. Taking a closer look at this dual-engine strategy helps explain how Boeing managed to create an aircraft with such legendary capabilities.