Wind is the determining factor. Airplanes have to take off and land into the wind. That is why runways at LAX and most other Southern California airports run east to west, said Richard Cox, manager of Terminal Radar Approach Control (TRACON), the radar facility on Imperial Highway that works with the LAX control tower.
Planes Head West
Usually, planes approach LAX along three major lanes from the east, north and south, with a few approaching from the Pacific Ocean. They are directed into two landing files that descend from the east over Inglewood or Lennox to the airport, Andersen said.
For takeoffs, the normal pattern is for planes to head west over the ocean. Those that have eastern destinations go north or south to flight paths that do not interfere with incoming traffic.
The Palmdale center regulates the flow of incoming planes above 13,000 feet and more than 40 miles away; TRACON tracks the planes between 5 and 40 miles away; and the Los Angeles control tower handles them once they are within 5 miles.
"And we all keep an eye on the weather," Andersen said. "We'll coordinate well in advance. We might say, 'Tomorrow we'll probably be turning the airport around at noon.' "
If the wind starts coming out of the east, reaches at least 10 knots and remains constant, the Los Angeles control tower makes a decision that involves Burbank airport, Ontario airport, John Wayne Airport and the control center at the El Toro Marine Air Station in south Orange County. The intricate process of reversing and rearranging air traffic, which started about 9 a.m. Thursday, takes about 15 minutes, officials said.
"Imagine a string of airplanes for 200 miles," said Dick Deeds of the Air Line Pilots Assn. "Sometimes at L.A. it's as long as 800 miles from the east. And all of a sudden those airplanes can't land for a while. It starts compressing like a spring."
A Headache for Controllers
The airport turnaround procedure is more of a headache for controllers than for pilots, Deed said, but pilots prefer the usual landing and takeoff approaches because they are used to them.
Officials designate the last airplane that will depart to the west and the first that will arrive from the west. Some planes are placed on holding patterns; others are held on the ground. Air space is reconfigured so that incoming flights from the east skirt LAX to the north and south, and approach from over the ocean. Departures are routed on eastward takeoff paths that vary, depending on the weather and the volume of air traffic, Cox said.
"It's not like they go as far as the Harbor Freeway every time and then turn," he said. "It all depends on the amount of traffic."
Cox and Andersen said the procedure is complicated and infrequent but poses no danger to travelers. It's toughest when the wind changes and strengthens suddenly, Andersen said.
"If it picks up to 15 to 20 knots we've got to do it quickly," he said. "Sometimes we'll have less than five minutes."
One advantage of the normal east-to-west pattern is that takeoffs, which are noisier than landings, occur mostly over the ocean. Turning the airport around increases noise over Lennox and Inglewood. But airport officials say they do not receive more complaints on such days.
"People know that it usually happens in a storm," said airport spokeswoman Pat Schoneberger. "Most of them know it's for safety and there's nothing we can do about it."
Most people in the area also know the rhythms of the airport well enough that they are not fazed when landing and takeoff directions change, officials said.