Tailhook - WikiHQ

thumb|Aircraft's tail hook catching the wire while landing on an aircraft carrier

thumb|F-15 tailhook. Most USAF tactical jet aircraft have tailhooks for emergency use.

A tailhook, arresting hook, or arrester hook is a device attached to the tail of some military fixed-wing aircraft. The hook is used to achieve rapid deceleration during routine landings aboard aircraft carrier flight decks at sea, or during emergency landings or aborted takeoffs at properly equipped airports.

The tailhook was first demonstrated at sea on 18 January 1911 by the aviator Eugene Ely, having successfully landed aboard the armored cruiser USS Pennsylvania with the aid of the device. It was not until the early 1920s that a practical system, paired with deck-mounted arresting gear, was devised and put into use. During the 1930s, numerous vessels were thus equipped, permitting the use of increasingly heavy combat aircraft at sea during the Second World War. Following the introduction of jet-powered aircraft during the 1950s, arrestor technology was further advanced to permit aircraft operating at greater speeds and weights to land aboard aircraft carriers. The system has continued to see widespread use into the twenty-first century.

History

thumb|F/A-18C tailhook with arresting wire

On 18 January 1911, the aviator Eugene Ely flew his Curtiss pusher airplane from the Tanforan airfield in San Bruno, California, and landed on a platform on the armored cruiser USS Pennsylvania anchored in San Francisco Bay,

While the system initially drew only limited attention, there was greater recognition of its merits following the outbreak of the First World War. During 1958, further testing took place using an arrangement of four Allison J33 turbojet engines.

While the tailhook is predominantly operated in a naval context, numerous land-based aircraft have also been fitted with them to assist with slowing down landings during emergencies. One highly unorthodox incident, known as "Pardo's Push", occurred during the Vietnam War in March 1967, involving a United States Air Force McDonnell Douglas F-4 Phantom II piloted by Bob Pardo assisting a second heavily damaged Phantom II in exiting the combat zone by pushing his aircraft against the other's deployed tailhook, reportedly halving its rate of descent temporarily.

In the twenty-first century, the tailhook has remained a part of the principal means of landing aircraft at sea for several navies, including the US Navy. During the 2000s, the Dassault Rafale, a French multirole fighter, became the only non-US fighter type cleared to operate from the decks of US carriers, using catapults and their arresting gear, as demonstrated in 2008 when six Rafales from Flottille 12F integrated into the Carrier Air Wing interoperability exercise. During the 2010s, new software trialled with the Boeing F/A-18E/F Super Hornet fighter reportedly showed promise in simplifying carrier landings.

During flight testing of the new Lockheed Martin F-35 Lightning II, one of the serious deficiencies that necessitated redesigns and delays was the failure of the navy's F-35C variant to catch the arresting wire in all eight landing tests; the tail hook had to be redesigned over a two-year period. Deficiencies have also been identified with the land-based F-35A's emergency tailhook. On 3 November 2014, the first successfully arrested landing of the F-35C was performed.

Description and operation

thumb|Man inspecting an [[F/A-18 tailhook prior to launch]]

The tailhook is a strong metal bar, with its free end flattened out, thickened somewhat, and fashioned into a claw-like hook. The hook is mounted on a swivel on the keel of the aircraft, and is normally mechanically and hydraulically held in the stowed/up position. Upon actuation by the pilot, hydraulic or pneumatic pressure lowers the hook to the down position. The presence of a tailhook is not evidence of an aircraft's aircraft carrier suitability. Carrier aircraft hooks are designed to be quickly raised by the pilot after use.

A large number of land-based fighters are also outfitted with tailhooks, which are intended for use in case of a brake/tire malfunctions, aborted takeoffs, or other emergencies. Land-based aircraft landing gear and tailhooks are typically not strong enough to absorb the impact of a carrier landing, and some land-based tailhooks are held down with nitrogen pressure systems that must be recharged by ground personnel after actuation.

Method

thumb|[[Mikoyan MiG-29K|MiG-29K with hook down]]

Prior to making an "arrested landing", the pilot lowers the hook so that it will contact the ground as the aircraft wheels touch down. The hook then drags along the surface until an arresting cable, stretched across the landing area, is engaged. The cable lets out, transferring the energy of the aircraft to the arresting gear through the cable. A "trap" is often-used slang for an arrested landing. An aircraft which lands beyond the arresting cables is said to have "boltered." Occasionally, the tailhook bounces over one or more of the wires, resulting in a "hook skip bolter."

In the case of an aborted land-based takeoff, the hook can be lowered at some point (typically about 1000 feet) prior to the cable. Should a tailhook of an aircraft become inoperative or damaged, naval aviators have limited options: they can divert to shore-based runways if any are within range, or they can be "barricaded" on the carrier deck by a net that can be erected.

References

Citations

Bibliography

United States Air Force. Guide To Mobile Aircraft Arresting System Installation. Retrieved on 3 November 2007.

External links

Aircraft carriers of the USA Navy