Unlike all other Navy H-60s, the MH-60S is not based on the original S-70B platform with its forward-mounted twin tail-gear and single starboard sliding cabin door.
Instead, the Sierra is a hybrid, featuring the main fuselage of the S-70A/UH-60, with large sliding doors on both sides of the cabin and a single aft-mounted tail wheel; and the engines, drivetrain and rotors of the S-70B/SH-60.