Building Barriers
The steel cable an aircraft's tailhook would grab in the event of an emergency is held slightly more than two inches off the ground, in part, by rubber donuts like this one and is one part of the BAK-12 aircraft arresting system. The donuts in the center of the runway are spray-painted so a pilot can more easily hook the center of the cable in the event of an emergency. (U.S. Air Force photo/Airman 1st Class Kyle Johnson)