deflector

A jet blast deflector (JBD) or blast fence is a safety device that redirects the high energy exhaust from a jet engine to prevent damage and injury. The structure must be strong enough to withstand heat and high speed air streams as well as dust and debris carried by the turbulent air. Without a deflector, jet blast can be dangerous to people, equipment, vehicles and other aircraft.
Jet blast deflectors range in complexity from stationary concrete, metal or fiberglass fences to heavy panels that are raised and lowered by hydraulic arms and actively cooled. Blast deflectors can be used as protection from helicopter and fixed-wing aircraft propwash. At airports and jet engine service centers, jet blast deflectors can be combined with sound-deadening walls to form a ground run-up enclosure within which a jet aircraft engine can safely and more quietly be tested at full thrust.

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