Plain English Meaning
A patch of special crushable concrete blocks built at the end of a runway. If a plane runs off the end, its wheels sink into the blocks and the plane is brought to a stop without crashing.
Full Definition
EMASMAX is the brand name of the Engineered Material Arresting System manufactured by Runway Safe, installed at the end of certain runways to safely stop an aircraft that overruns the runway. It consists of a bed of crushable cellular cement blocks that collapse predictably under the weight of an aircraft's wheels, decelerating it without causing major structural damage to the airframe or injury to occupants.
Context Anchor
Seen in runway safety discussions, airport planning information, and pilot guidance about what may be located beyond the of a runway.