OCR Text |
Show GROOVY RUNWAYS FOR SAFETY Diaiiiond-blndi-d iiuuhincs are used to cut narrow grooves across runway to prevent skidding during wet weather. Parallel grooves across an airport air-port runway provide a safety factor in wet weather that commercial com-mercial airline pilots say is equal to an additional 2.000 feet of runway. When planes land or take off in the rain, they run the risk of skidding because of a weird phenomenon called hydroplaning. hydroplan-ing. There is a possibility that a cushion of water will form under un-der the craft's tires. Should this happen, the tires mount and ride on a solid sheet of water, much in the way that a surfboard surf-board rides the crest of a wave. There is absolutely no contact between the tires and the runway. run-way. The pilot loses control of his craft when hydroplaning occurs. The plane may then overshoot or run off the runway. Fortunately, NASA and other government researchers have found a cure for wet-weather skids caused by hydroplaning. The solution is to cut into the runway shallow grooves about 14 in. deep and VI in. wide, with about 1 in. between grooves. Machineswithdiamond blades cut precise grooves across the runway, perpendicular to the plane's direction of travel. Their purpose is to provide escape routes for the water, leading it away before it can form a skid-causing skid-causing cushion. Runway grooving has been carried out in the past IV2 years at Washington's National Airport, Air-port, New Yorks J.F. Kennedy, Kansas City's Municipal, and Chicago's newly remodeled Midway Mid-way Airport. In tests at military bases, jet fighter pilots say that where usually us-ually 10,000 feet is needed to stop on a wet runway, they can halt in under 4.500 feet on a grooved surface. |