Free from bird-hits

New technology promises to keep birds away from airplanes

Published: Sunday 31 October 1999

in 1975, a dc -10 taking off from New York City's John F Kennedy airport lost one of its three engines when it ran into a flock of seagulls. The plane slid off the runway and caught fire, but no one was hurt. The passengers of a Boeing 707, however, were not so lucky. Four years ago, this plane struck a flock of geese during takeoff; it lost two of its four engines and crashed. All 24 people on board were killed.

There are numerous such instances reported all over the world. Every year in the us, pilots report more than 5,000 bird strikes that cause more than us $400 million in damages to commercial and military aircraft. The Federal Aviation Administration ( faa), which has been experimenting with everything -- from electromagnetic to ultrasonic devices to scarecrows -- is yet to come up with a solution to keep birds out of the path of oncoming aircraft.

Bird strikes were not as common in the us some 30 years ago as they are at present. This was because the bird population was low. But thanks to conservation efforts such as a ban on pesticides like ddt in some countries and broadening of the Migratory Bird Treaty Act in 1972, the bird population has increased. In Canada, for example, the goose population was about 600,000 in the mid-80s. Today, its population is more than two million. With increasing deforestation and humans taking over their old habitat, birds have made open spaces like airports their home.

Some experts believe that the only option to this problem is to understand the behaviour of birds. They say that birds are sacred of radars. With this belief, some researchers may have a solution to this problem. Jim Genova of the Defence Research Associates in Washington, dc , is working on a project based on research begun in the 1960s by biophysicist A H Frey who discovered that humans had the ability to hear radar. He experimented with his students who were able to hear sounds coming out of microwave transmitters. The theory was that the microwaves caused pulses of heat in the brain, which expanded and contracted the cochlea. Genova used this theory on birds.

Taking Frey's theory one step ahead, Genova and his colleagues set up a microwave transmitter on to a truck and set free a cage of wild birds. As the transmitter was switched on, the birds were startled and did their best to fly out of the vehicle's path more quickly than when the transmitter was switched off. "The tweaking of pulses sent out by a common aircraft transmitter, called distance-measuring equipment ( dme) , can turn a ubiquitous aircraft instrument into a warning siren for the birds," Genova says.

He now plans to mount a modified dme on a small plane and let loose a flock of birds towards the aircraft to see if his technique works. Pilots around the world hope that his experiment succeeds.

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