Arrestor Hooks- Avionics

Q1. You are to give an explanation of an aircraft’s arrestor hook retardation system.

* With regards to its function.

* The operation of the systems main components.

Landing on a flight deck is very difficult to do considering the length of the runway is about 500 feet and the aircraft are usually heavy, high speed jets. To allow aircraft to land safely on the runway, a tail hook is attached to the aircrafts tail where arresting wires hook onto the tail hook to allow the aircraft to stop very quickly. This system can stop a 54,000 pound aircraft that is traveling at the speed of 150 mph in only two seconds.

The Arrestor hook system can be mechanically or electrically operated. To operate the aircraft mechanically the pilot would select the hook down. This is usually a handle that is connected by cables and levers to release the up locks. The arrestor hook arm will retract in the over centre condition and is locked. A red warning lamp in the cockpit is illuminated by a micro switch to alert the pilot of the transition.

To stop the hook bouncing on the runway when lowered the system also has a spring jack. When the hook snags the arrestor wire the aircraft will stop quickly. The wires are attached to a hydraulic cylinder system that absorbs the energy of the aircraft.

Once stopped the pilot will then need to release the tension from the arrestor wires by moving the aircraft backwards. To do this he will release the brakes and move the aircraft backwards.

Finally the pilot will raise the hook by selecting the handle in the hooks up position. When the handle is pulled the cables will transmit the movement to retract the hooks up. Once the arrestor hook is fully retracted and locked the red lights in the cockpit will go off indicating that the system is not in use.

Q2. You are to give an explanation a generic aircraft normal and anti-skid brake systems.

* With regards to its function.

* The operation of the systems main components....