Arrestor cables
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An aircraft about to catch the wire |
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An aircraft coming to a stop, with the arrestor cable housing in the foreground |
Arrestor cables or
arrestor wires are thick steel cables fitted to the aft end of the
flight deck on
CATOBAR and
STOBAR aircraft carriers. The cables allow
aircraft to land safely on the short
runway by catching one of these cables with a
tailhook.
Most aircraft carriers have four cables, numbered from the stern (rear) of the ship to the bow (front). In
US Navy parlance, the aft (rear) cable is "Wire 1", and the forward (front) wire is "Wire 4". In a "perfect" carrier landing, the tailhook catches Wire 3. The aircraft then pulls the cable out of its housings, against tension provided by a
hydraulic mechanism that decelerates and stops the aircraft. This tension is adjustable; if it is too weak, it will not stop the aircraft before the end of the flight deck, but if it is too strong, it may severely damage the aircraft. Pilots about to land are required to confirm their aircraft type and fuel state, so the cables can be set for the aircraft's landing weight.
Because there is always the possibility of the aircraft not catching any of the cables, pilots bring the aircraft to full throttle as the aircraft contacts the landing surface. This technique allows an aircraft which misses all of the cables to have enough speed to go off the end of the deck at flying speed and
go around for another approach. An aircraft that misses all of the cables is called a "bolter".
Some military
airfields are also equipped with arrestor cables to permit the landing of heavy or fast aircraft on a short runway; for training naval aviators prior to carrier deployment; or for emergencies involving brake failure, steering problems, or other situations in which a full landing rollout would be dangerous or inadvisable. Arrestor cables attached to
sandbags can also be used to stop an aircraft with failed
brakes; the aircraft will drag the sandbags along the ground, slowing it to a halt.
An idea of arrestor cables was first invented by
Hugh Robinson and utilized by
Eugene Ely on his first landing on a ship - the
armored cruiser USS Pennsylvania, on
January 18,
1911. The cables were just attached to sandbags then. More modern arrestor cables were tested on
HMS Courageous in June 1931.
Henry Fancourt was the first pilot to land using the new system.
