BACKGROUND: Major airports around the country will be safer after they implement a new Federal Aviation Administration standard to help prevent collisions on runways by providing pilots with better visual cues. The new standards are based on recent findings from the Enhanced Surface Markings Project, a collaboration between human factors/ergonomics consultants, the FAA and representatives from aviation industry. The goal was to make runway and taxiway markings more conspicuous and usable while still preserving the essential elements of current markings to keep additional training and extra confusion to a minimum. The new markings are currently being used by eight major airports, and will be mandatory for 72 major U.S. airports by June 2008.
ABOUT THE STUDY: Ironically, one of the most complex phases of flight occurs not in the air but on the ground, while taxiing to and from the gate. Low-cost but highly effective alterations in the way that lines are painted on runways and taxiways cold help pilots and ground and tower control personnel to navigate busy runways. One change is modifying the centerline extending 150 feet from the runway holding position with a pattern of dashes on either side, to give a "preview" to the pilots that a runway is approaching. The second change is placing surface-painted holding position signs at all runway intersections and on both sides of the centerline. A third recommendation was not adopted by the FAA: modifying the runway hold line with white dashes instead of yellow, to indicate the runway side and not the taxiway side. A total of 224 pilots participated in the study.
HOW AIRPLANES FLY: Aerodynamic theory rests on two pairs of opposing forces: lift and weight (the pull of gravity), and thrust and drag. A moving body exchanges kinetic energy for potential energy as it gains height. A similar phenomenon occurs with a moving fluid, like air: It exchanges its kinetic energy for pressure. This is the Bernoulli Principle. It simply states that the pressure of any fluid decreases where the speed of the fluid increases. So high-speed flow is linked to low pressure and low-speed flow to high pressure. An airplane's wings are designed to create an area of fast-flowing air (and hence low pressure) above the surface. It doesn't matter whether the object is moving through still air, or whether the air moves around the object. It's the relative difference in speeds between the two that create lift. A wing is basically an airfoil, with a leading edge that is angled to "attack" the air in such a way that it increases the speed of the airflow above the wing, decreasing the pressure there. The air pressure underneath the wing becomes greater than above, and that combination produces lift. When the lift becomes greater than the object's weight, the object will begin to rise.
The Human Factors and Ergonomics Society contributed to the information contained in the TV portion of this report.