The stairs are actually part of the door rather than an attached stair. This design is efficient and because the aircraft which use it sit low to the ground, the design can stay simple and not add complexity or weight to the design, one of the biggest problems with airstair assemblies. The design has also been used with a single-length set of extension stairs on aircraft such as the cargo compartment of the widebody Ilyushin Il-86 (the primary entrance to the aircraft for passengers), Boeing VC-25, and the belly lounges of three Lockheed L-1011s.