RAF UPPER HEYFORD EMERGENCY ARRESTER GEAR - MARCH 2011

Another small but significant building myself and BK visited today was out on the main runway:thumb

Description:-

The Airfield arrester gear, is located in two buildings located approximately 1500ft from each side of the runway in two white buildings. The wire ran through two tunnels underground from the buildings.
The wire is tensioned across the runway at each end and terminates into a strong nylon webbing which is wound around a pulley.

The cable across the runway is usually left resting in contact with the surface. Just before an emergency landing, the airfield arrester party or fire section will go to the Arrester site nearest the approach threshold and pull out a series of nylon discs which are bunched up at each end of the cable, these when pulled out are spaced about 5ft from each other and cause the cable to be raised a few inches of the tarmac.

The basics of the working system is that the aforemention pulley sits above a chamber full of fluid, as the cable is pulled out by an emergency engagement the pulley spins fairly fast, paddles below it have to move through the fluid, which as they spin cause a viscosity change in the fluid. This in turn slows down the pulley and brings the aircraft to a stop.
The two white buildings are anchored heavily underground so that an incoming aircraft does not rip the buildings out of the ground as the aircraft hook catches the wire and spins the pulleys.

The cables' position on the runway is maked by large yellow discs painted on the tarmac, and by a marker board at each end of the cable, with yellow illiminated discs on it this is a location marker for the incoming pilot.

On with the pics:thumb

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One of 2 buildings which contained the pulleys that the arrester wire was wound around! Today the buildings are empty with all controls having been removed:(

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Looking from the runway towards the control building with the wire tunnels present. The yellow warning illuminated sign was so that pilots would recognise the postion of the wire, so that the planes arrestor hook could be lowered in time:thumb

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Close up of the arrester wire tunnels, the bolts in the ground supported two tension pulleys which the cable ran through.

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The cables path can still be clearly seen today across the runway, even though the wire was removed back in 1994:thumb The yellow discs on the runway marked the cables position.

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Once past the cable! The runway quickly runs out:D