Runways
Runways are amazing -- a typical one is about 2 miles long, as wide as a 16-lane highway and about 3 feet thick!
Think about this: A fully-loaded 777 or 747-400 weighs about 850,000 pounds (385,554 kg). Imagine a rough landing where 850,000 pounds slams down hard onto the runway. Runways have to be specially constructed to take that strain without cracking or, worse, buckling. As they're designing runways, engineers have to consider the number of wheels an airplane has, how far apart those wheels are and the size of the tires. As planes get bigger and bigger, runways have to be re-built to accommodate the increased stresses.
When the Denver International Airport was built, it took 2.5-million cubic yards of concrete to create five 12,000-foot runways, plus taxiways and aprons. First, 6 feet of compacted soil was put down; then, a foot-deep layer of soil was spread, topped by an 8-inch-thick cement-treated base; that was followed by 17 inches of concrete paving.
Main runways are usually oriented to line up with the prevailing wind patterns so that airplanes can take-off into the wind and land with it. Local and ground air traffic controllers determine which runways are used for take-off and which for landing, taking into account weather, wind and air-traffic conditions. In some airports, main runways cross each other, so the controllers have to pay even closer attention.
 Photo courtesy Lufthansa A 747 Jumbo Jet lands on a main runway. |
Planes use taxi runways to get from the gate to a main runway for take-off and from a main runway to the gate after landing. Ground controllers direct ground traffic from the airport's tower. Airline ground personnel assist with the push-back and arrival of aircraft in the gate areas, driving the tugs that push the aircraft back and directing traffic with those glowing wands.
 Photo courtesy Lufthansa A 747 Jumbo Jet is directed to the gate from the taxi runway. |
Now let's take a quick look at how airports provide jet fuel.
