February 1, 2007 The Federal Aviation Administration's new Enhanced Surface Markings Project, developed with the help of human factors engineers, promises to reduce the number of collisions on airport runways. The new markings are a pattern of dashed lines on both sides of a center line located 150 feet before a plane reaches a runway, giving pilots more warning of an upcoming runway. The new standards will also help drivers of surface vehicles like baggage carts, fuel trucks and maintenance carts, which are involved in 20 percent of runway accidents.
Many frequent flyers are familiar with taxi and take-off waits on airport runways. The wait is frustrating for passengers, but pilots need to pay extra attention while near or on a runway.
In August 2006, a pilot mistakenly used the wrong runway in Lexington, Ky., crashed and killed everyone on board but himself. The largest accident in history happened in 1977 when two planes collided on a runway, killing 583 people. A confusing, complex sea of lights, markings, signs and lines were some of the factors that lead to the crashes.
"Once you miss one runway sign, then you can easily find yourself taxiing onto a portion of the airport surface, where you aren't entirely sure that you should be at that time," Ron Stevens, a pilot with MITRE's Center for Advanced Aviation System Development in McLean, Va., tells DBIS.
Now, human factors engineers have designed new surface markings to help safely guide pilots on runways.
"What we were trying to do is modify those markings to give some preview information to the pilot that you're beginning to approach a runway," MITRE Engineer Oscar Olmos tells DBIS.
The new markings are a pattern of dashed lines on both sides of a center line located 150 feet before a plane reaches a runway. The line-pattern change gives pilots more warning of an upcoming runway and helps eliminate possible accidents.
Olmos says, "The biggest benefit is just runway safety, being sure that the pilots feel comfortable with where they're at on an airport and they're not inadvertently going onto the runway when they shouldn't be."
Pilots testing the new markings agree, the new markings help make runways safer. As a result, the FAA is requiring all major airports to implement the new markings by 2008. The new line-pattern designs will also help drivers of surface vehicles like baggage carts, fuel trucks, and maintenance carts, given that 20 percent of runway accidents between 1999 and 2002 involved these vehicles.
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 video portion of this report.