Airstair

This article is about stair units integrated into aircraft. For mobile stairways for boarding and alighting aircraft, see boarding stairs.
Northwest Airlines Boeing 727 with rear airstair deployed
DC-3 modified with a simple airstair
Cubana de Aviación Yak-42D with rear airstair deployed
Airstairs on the side of a "Combi" 737-200 aircraft of Alaska Airlines
George W. Bush boards a VC-25 via airstairs. These airstairs do not exist on regular 747 aircraft.

An airstair is a set of steps built into an aircraft so that passengers may board and alight the aircraft. The stairs are often built into a clamshell-style door on the aircraft. Airstairs eliminate the need for passengers to use a mobile stairway or jetway to board or exit the aircraft, providing more independence from ground services. Some of the earliest aircraft to feature airstairs were the Martin 2-0-2 and Martin 4-0-4. Some models of the Douglas DC-3 were also retrofitted with airstairs (see picture). As airport infrastructure has developed, the need for airstairs has decreased, as jetways or mobile stairways are often available.

Wide-body aircraft rarely employ airstairs, as the doors are significantly higher above the ground than narrow-body aircraft. One notable exception is the Lockheed L-1011, the only wide-body aircraft to feature full-height airstairs. The only other wide-bodies with airstairs, the VC-25 and the Ilyushin Il-86, have airstairs contained in the cargo hold, with steps inside the cabin to access these stairs.

Some aircraft, like the Boeing 727 and McDonnell Douglas DC-9, were designed to improve ground services, with passengers deplaning from the front as the aircraft is serviced from the rear, enabling quicker turnarounds.

Airstairs are also used as a security measure, for example on aircraft carrying the President of the United States, allowing the aircraft to be boarded by VIPs at any time - with or without the cooperation of ground services.