Jan. 15--LONG BEACH -- It is a deadly legacy that Long Beach Airport does not want any part of, unless it's in the role of preventing future chapters from being written.
March 1977: Two jumbo jets collide on the runway in Tenerife, Canary Islands. With 583 people killed, it's the world's deadliest aviation accident.
February 1991: Thirty-four people are killed when a USAir 737 collides with a Skywest Metroliner on a Los Angeles International Airport runway.
July 2006: A United Airlines 737 and Atlas Air 747 cargo plane nearly collide, coming within 35 feet of each other as they were on intersecting runways.
January 2007: A Frontier Airlines flight takes a last-second maneuver to avoid hitting a smaller Metroliner taxiing on a runway at Denver International Airport.
All four were caused by one of the most nagging problems at U.S. airports, runway incursions -- incidents, some with tragic results, where airplanes collide or come perilously close while accidentally traveling on the same landing strip.
The planes may be using a taxiway and crossing a runway to get to the terminal while another incoming passenger jet gets ready to take off or land. Or an incoming aircraft may not spot another already on the runway -- a phenomenon called "rearward conspicuity," the inability to see an airplane's "behind," especially at night or during bad weather.
With an annual rate of 63 million takeoffs and landings across the U.S. annually, reducing runway incursions is a top priority of the Federal Aviation Administration.
Already FAA initiatives like pilot education have helped reduce "serious" runway incursions by 40 percent over the last five years.
A serious incursion is one where a plane has to take extreme actions to avoid a collision, or a collision actually happens.
But that downward trend has flattened out, and there are estimates that a runway incursion happens once a day in the U.S., which has prompted a search for even more prevention measures.
One of the most promising tools is in the early stages of a year-long evaluation at Long Beach Airport's 10,000-foot-long primary runway.
The potential solution appears almost simplistic in its design: a bank of four lights alongside the runway blink a warning to airborne pilots on approach whenever another airplane enters danger "zones" on the landing strip.
The lights blaze steadily when the runway is clear. But when planes on the ground make a turn off taxiways onto or across the runway, they trip buried sensor loops and the lights begin blinking their warning.
Pilots can use that information to scan the runway for obstructions, decide to fly over the runway and reapproach, or consult with air traffic controllers or the airport tower to determine if the problem may clear up.
The FAA decided to use Long Beach Airport to test the Final Approach Runway Occupancy Signal (FAROS) system because it has a complicated network of five runways that intersect with each other and with multiple taxiways.
It is also one of the busiest general aviation airports in the country, with nearly 370,000 annual flights originating there. The activity involves a mix of landings and takeoffs involving blimps, helicopters, charter and corporate planes, military cargo planes, banner towing aircraft and small general aviation craft.
Long Beach also had existing infrastructure and equipment from previous FAA tests that could be modified to develop FAROS.
Sensor loops are imbedded in the runways to detect when planes cross from taxiways onto the main runway, alerting the control tower. When combined with ground radar it gives a fuller picture of activity.
Traditional Precision Approach Path Indicator (PAPI) lights also are installed at the airport and used by planes to determine if they are approaching at too high or too low an altitude.