Airstair

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Northwest Airlines Boeing 727 with rear airstair deployed Rwr727tail.jpg
Northwest Airlines Boeing 727 with rear airstair deployed
Cubana de Aviacion Yak-42D with rear airstair deployed Cubana in SdC.JPG
Cubana de Aviación Yak-42D with rear airstair deployed
Airstairs on the side of a "Combi" 737-200 aircraft of Alaska Airlines Wrangell Alaska Airlines Combi.JPG
Airstairs on the side of a "Combi" 737-200 aircraft of Alaska Airlines
George W. Bush boards a VC-25 via airstairs. Air Force One June 12 2006.jpg
George W. Bush boards a VC-25 via airstairs.

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. [1] As airport infrastructure has developed, the need for airstairs has decreased, as jetways or mobile stairways are often available.

Contents

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.

Design

Ventral airstairs are featured on most tail-engined airliners, such as the Boeing 727, the McDonnell Douglas DC-9, MD-80 and MD-90, the BAC 1-11, and the Yakovlev Yak-40/Yak-42 series, and are incorporated as ramps which lower from the fuselage. The Ilyushin Il-86 has three airstairs on the port side.

The most common type of airstair is found in most business aircraft, regional jets, and other small airliners, which is a stair built into the inside of the main passenger door, which is lowered to the outside. Aircraft such as the Fokker F-28 series and the VFW-Fokker 614 made this design popular. 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.

Another widespread type of airstair is used for forward doors. The stair folds and stows under the floor of the door and is deployed from the fuselage immediately below the forward door. This type of airstair is found on many short-range aircraft such as Boeing 737s, DC-9s, and some Airbus A320 series aircraft. The mechanism is also quite heavy; as a result, many airlines have removed this system to reduce aircraft weight.

A unique airstair design was used for the aft doors of 737 Combi aircraft, which consisted of a clamshell door which dropped down to open much like a business aircraft, but then had stairs which were stored trifold in the curve of the door, which would unfold to the ground. This system was very cumbersome, was very susceptible to damage, and thus has been removed by many of its users.

The most unusual airstair design was found on the Lockheed L-1011, which was a full-height airstair which was stored in a cargo compartment and allowed access from the right aft passenger door to the ground. This design was ultimately so large and heavy, and it took up valuable cargo space, that it was rarely used.

The original On-Board Folding Airstairs were designed by Winters Aircraft Engineering Company over 30 years ago. Airweld Incorporated is the current STC holder and has FAA PMA for all of the original STC’s issued to Winters, as well as STC’s issued to subsequent manufactures including Kaiser Aerospace, WAPCO, and Advanced Aerospace. The On-Board Folding Airstairs can be found in use on many U.S. and Foreign Military and Government Aircraft including the Boeing E4B as well as VIP aircraft around the world. The On-Board Folding Airstairs is a multi-section (3, 4, or 5 segment) airstair that can be installed at either the forward, center, or aft doors. When retracted/closed, the airstair sits on a track and is typically stowed in a closet either Forward, Aft, or Transverse.

As a parachuting exit

An animation representing D. B. Cooper parachuting from the rear airstair of the Northwest Orient Boeing 727 he hijacked (Click to view animation) 727db.gif
An animation representing D. B. Cooper parachuting from the rear airstair of the Northwest Orient Boeing 727 he hijacked (Click to view animation)

A rear, ventral, airstair can be used as a safe means of parachuting from an airliner that is equipped with one. This was attempted on 24 November 1971 by an unknown hijacker, widely known as D. B. Cooper, who jumped from a Boeing 727 along with US$200,000 in ransom money. [2] However it is unknown if he survived the jump. Subsequently, a number of individuals carried out copycat hijackings against Boeing 727s and safely parachuted to the ground, although all were apprehended by the authorities. To prevent this, Boeing 727s were ordered to be fitted with a simple device known as a Cooper vane that prevented the ventral airstair from being opened in flight. [3]

The rear airstair of a DC-9 has been used to allow for recreational skydiving operations. [4]

During the 2012 Boeing 727 crash experiment, a flight crew took off in the Boeing 727 that was to be crashed and flew it to a pre-selected desert site before safely parachuting from the airstair, as the Mexican government required that the plane be flown by a human crew for part of the experiment, especially as the aircraft's route to the crash site passed over populated areas. The 727 was then deliberately flown into the ground under remote control. [5]

See also

Related Research Articles

Airliner Aircraft designed for commercial transportation of passengers and cargo

An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an airplane intended for carrying multiple passengers or cargo in commercial service. The largest of them are wide-body jets which are also called twin-aisle because they generally have two separate aisles running from the front to the back of the passenger cabin. These are usually used for long-haul flights between airline hubs and major cities. A smaller, more common class of airliners is the narrow-body or single-aisle. These are generally used for short to medium-distance flights with fewer passengers than their wide-body counterparts.

Boeing 727 Narrow body jet airliner

The Boeing 727 is an American narrow-body airliner produced by Boeing Commercial Airplanes. After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller airports. On December 5, 1960, the 727 was launched with 40 orders each from United Airlines and Eastern Air Lines. The first 727-100 rolled out November 27, 1962, first flew on February 9, 1963, and entered service with Eastern on February 1, 1964.

Lockheed L-1011 TriStar American medium-to-long-range, wide-body trijet airliner

The Lockheed L-1011 TriStar, commonly referred to as the L-1011 or TriStar, is an American medium-to-long-range, wide-body trijet airliner by Lockheed Corporation. It was the third wide-body airliner to enter commercial operations, after the Boeing 747 and the McDonnell Douglas DC-10. The airliner has a seating capacity of up to 400 passengers and a range of over 4,000 nautical miles (7,410 km). Its trijet configuration has three Rolls-Royce RB211 engines with one engine under each wing, along with a third engine center-mounted with an S-duct air inlet embedded in the tail and the upper fuselage. The aircraft has an autoland capability, an automated descent control system, and available lower deck galley and lounge facilities.

McDonnell Douglas DC-10 Wide-body tri-jet airliner

The McDonnell Douglas DC-10 is an American wide-body airliner manufactured by McDonnell Douglas. The DC-10 was intended to succeed the DC-8 for long range flights. It first flew on August 29, 1970; and was introduced on August 5, 1971 by American Airlines.

Boeing 757 Airliner family by Boeing

The Boeing 757 is an American narrow-body airliner that was designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the 727, received its first orders in August 1978. The prototype completed its maiden flight on February 19, 1982 and it was FAA certified on December 21, 1982. Eastern Air Lines placed the original 757-200 in commercial service on January 1, 1983. A package freighter (PF) variant entered service in September 1987 and a combi model in September 1988. The stretched 757-300 was launched in September 1996 and began service in March 1999. After 1,050 had been built for 54 customers, production ended in October 2004, while Boeing offered the largest 737 NG variants as a successor.

Wide-body aircraft Aircraft with two aisles

A wide-body aircraft, also known as a twin-aisle aircraft, is a jet airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast. The typical fuselage diameter is 5 to 6 m. In the typical wide-body economy cabin, passengers are seated seven to ten abreast, allowing a total capacity of 200 to 850 passengers. The largest wide-body aircraft are over 6 m (20 ft) wide, and can accommodate up to eleven passengers abreast in high-density configurations.

Jet airliner Passenger aeroplane that is powered by jet engines

A jet airliner or jetliner is an airliner powered by jet engines. Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly classified as either the large wide-body aircraft, medium narrow-body aircraft and smaller regional jet.

This is a list of aviation-related events from 1980:

Cooper vane

A Cooper vane is a mechanical aerodynamic wedge that prevents the ventral airstair of an aircraft from being lowered in flight. In the United States, following three hijackings in 1972, the Federal Aviation Administration ordered that Boeing 727 aircraft be fitted with Cooper vanes. The device was named for an unidentified airplane hijacker dubbed D. B. Cooper, who used the rear stairway to exit a Boeing 727 in flight and make his escape via parachute.

Combi aircraft

Combi aircraft in commercial aviation are aircraft that can be used to carry either passengers, as an airliner, or cargo as a freighter, and may have a partition in the aircraft cabin to allow both uses at the same time in a mixed passenger/freight combination. The name combi comes from the word combination, and is derived from the famous Volkswagen Type 2 van, often called the "Kombi" van, specifically the Kombinationskraftwagen variant, with side windows and removable rear seats, which both a passenger and a cargo vehicle combined.

Cargo aircraft Aircraft configured specifically to transport cargo

A cargo aircraft is a fixed-wing aircraft that is designed or converted for the carriage of cargo rather than passengers. Such aircraft usually do not incorporate passenger amenities and generally feature one or more large doors for loading cargo. Freighters may be operated by civil passenger or cargo airlines, by private individuals or by the armed forces of individual countries.

McDonnell Douglas DC-9 Twin-engine, single-aisle jet airliner produced 1965-1982

The McDonnell Douglas DC-9 is a single-aisle airliner designed by the Douglas Aircraft Company. After introducing its heavy DC-8 in 1959, Douglas approved the smaller, all-new DC-9 for shorter flights on April 8, 1963. The DC-9-10 first flew on February 25, 1965 and gained its type certificate on November 23, to enter service with Delta Air Lines on December 8. With five seats across in economy, it had two rear-mounted Pratt & Whitney JT8D turbofans under a T-tail for a cleaner wing, a two-person flight deck and built-in airstairs.

Trijet

A trijet is a jet aircraft powered by three jet engines. In general, passenger airline trijets are considered to be second-generation jet airliners, due to their innovative engine locations, in addition to the advancement of turbofan technology.

Double-deck aircraft

A double-deck aircraft has two decks for passengers; the second deck may be only a partial deck, and may be above or below the main deck. Most commercial aircraft have one passenger deck and one cargo deck for luggage and ULD containers, but only a few have two decks for passengers, typically above or below a third deck for cargo. Most of them are disappearing.

S-duct

An S-duct is a type of jet engine intake duct used in several types of trijet aircraft. In this configuration, the intake is in the upper rear center of the aircraft, above or below the stabilizer, while the exhaust and engine is at the rear of the aircraft. The S-duct is located in the tail, or empennage, of the aircraft. The shape of the S-duct is distinctive and easily recognized, and was used in several aircraft, beginning in 1962 with the Hawker Siddeley Trident. Currently, the Dassault Falcon 8X and Dassault Falcon 900 business jets are the only aircraft in production that use the S-duct design.

References

  1. Simpson, Martin J. "A-26 Access and Air Stairs". Tripod.com. Retrieved 25 July 2012.
  2. Krajicek, David (1 August 2011). "D. B. Cooper, the legendary daredevil". TruTV. Archived from the original on 2013-12-10. Retrieved 25 July 2012.
  3. Bruce Schneier (2003). Beyond Fear: Thinking Sensibly about Security in an Uncertain World . Springer Science & Business Media. p.  82. ISBN   0-387-02620-7. Cooper vane.
  4. https://skydiveperris.com/experienced/facilities
  5. 'Curiosity: Plane Crash' Documents Intentional Boeing 727 Crash. ABC News. Event occurs at 0m 48s.