Tutorial

3. Runway Lighting and Markings
It is relatively easy to navigate around small airports, but large airports can be a nightmare for pilots using them for the first few times. Pilots can inform the ground controller they are unfamiliar with the airport, and request progressive taxi instructions. The ground controllers are happy to help newcomers. The airborne view of Dallas/Ft. Worth airport will give you a picture of how complex and confusing a large airport can be to pilots who do not work out of DFW regularly. The view looking north shows nine runways and dozens of taxiways and high-speed turnoffs. When one thinks of an airport, one pictures a control tower. Dallas International Airport (DFW) uses not one, but three control towers to control the air and ground traffic. One tower controls the east side of the airport, a second tower controls the west side of the airport and a third tower controls the center.

Airports also use standardized lighting and ground markings to provide direction and identification to all air and ground crews. To assist pilots in differentiating at night between airport runways and freeways, airports have rotating beacon lights. These beacons usually flash green and white lights to indicate a civilian airport. These beacons are visible from the air long before the entire airport is recognizable. To help pilots at night quickly identify the beginning of a runway, green threshold lights line the runway's edge. Red lights mark the ends of runways and indicate obstructions. Blue lights run alongside taxiways while runways have white or yellow lights marking their edges. All these markings and lights serve to set a safety standard for all pilots to follow.

Taxiways are given letter names like taxiway "Alpha", "Foxtrot", "Hotel" according to the International Phonetic Alphabet. They are indicated on signs by just their letter: "A", "F", "H". If the letter is followed by an arrow, the arrow indicates the direction the aircraft must turn in order to maneuver the aircraft onto that taxiway. Sometimes taxiways are designated by a letter followed by a number (letter-number combination). This is to distinguish it from runways which are designated by just a number or a number-letter combination.

Direction sign for runway exit Destination sign for common taxiing route to two runways Destination sign for different taxiing routes to two runways

In navigation and surveying all measurement of direction is performed by using the numbers of a compass. A compass is a 360° circle where 0/360° is North, 90° is East, 180° is South, and 270° is West. Runways are laid out according to the numbers of a compass. A runway's compass direction is indicated by a large number painted at the end of each runway. Preceding that number are 8 white stripes. Following that number by 500 feet is the "touchdown zone" which is identified by 6 white stripes. A runway's number is not written in degrees, but is given a shorthand format. For example, a runway with a marking of "14" is actually close to (if not a direct heading of) 140 degrees. This is a southeast compass heading. A runway with a marking of "31" has a compass heading of 310 degrees, that is, a northwest direction. For simplicity, the FAA rounds off the precise heading to the nearest tens. For example, runway 7 might have a precise heading of 68 degrees, but is rounded off to 70 degrees.

Each runway has a different number on each end. Look at the diagram below. One end of the runway is facing due west while the other end of the runway is facing due east. The compass direction for due west is 270 degrees ("27"). The compass direction for due east is 90 degrees ("9"). All runways follow this directional layout. This runway would be referred to as "Runway 9-27" because of its east-west orientation.

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Parallel runways are identified as left or right. A clearance to land on one of two parallel runways would have the runway number followed by an "L" or "R". So two parallel runways oriented 90 and 270 degrees would be numbered "9L" and "9R" and "27L" and "27R." If there were three parallel runways the center runways would be "9C" and "27C."

As a general rule, runways are numbered relative to magnetic north rounded to the nearest ten degrees. An exception to this rule is Dallas Ft. Worth International Airport (DFW). DFW has five north-south runways all oriented true north-south, 180 and 360 degrees. The magnetic headings of all five runways are 174-354 degrees. IF DFW followed the rule then all five would be numbered "17-35." However that would cause a problem. How would an aircraft cleared to land know which 17-35 runway to use? The solution was to number the three east runways 17-35 left, center and right (17L, 17C, 17R and 35L, 35C and 35R). The two west runways are marked 18-36 left and right (18L, 18R and 36L, 36R). This does not follow the rule, but it does prevent confusion.

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