Editor's note: We're posting this story from our September 1999 issue because of the bird strike to US Airways flight 1549 in New York City on Thursday.
Airplanes and birds just can’t get along. Every year pilots in the U.S. report more than 5,000 bird strikes, which cause at least $400 million in damage to commercial and military aircraft. Although any airborne encounter is going to be harder on the bird (just ask romance-novel cover boy Fabio, who encountered one while riding a roller coaster), the damage the animals can inflict on aircraft control surfaces or engines can lead to disaster. In 1975 a DC-10 taking off from New York City’s John F. Kennedy airport ran into a flock of seagulls and lost one of its three engines; the airliner slid off the runway and burned, although everyone on board escaped unharmed. Four years ago the crew of a U.S. Air Force AWACS plane wasn’t so lucky. The Boeing 707 lost two of its four engines after striking a flock of geese during takeoff; the crash killed all 24 people on board.
Despite having experimented with everything from electromagnetics to ultrasonic devices to scarecrows, the Federal Aviation Administration (FAA) has yet to endorse one single sensational solution that will keep birds out of the path of an oncoming aircraft. The best bet right now is understanding bird behavior, although an intriguing old pilots’ tale—that radar can scatter birds—may carry enough truth to ultimately offer a viable technical solution to a deadly problem.
Before the 1970s, bird strikes were rare, partly because bird populations were at an all-time low. But conservation efforts—including banning such pesticides as DDT and broadening the Migratory Bird Treaty Act in 1972—have paid off big: the Canada goose population, for instance, about 600,000 in the mid-1980s, exploded to two million birds in a decade. With humans taking over the birds’ old habitats, flocks of protected species have made a home out of the wide-open spaces of international airports, which tend to be built along migratory flight paths on once undesirable, now federally restored and protected wetlands. “Birds don’t seek a kindred spirit there,” explains Ed Cleary, staff wildlife biologist for the FAA. “They see habitat that is attractive to them.”
At first, airports’ efforts to control birds had a whimsical, Seussian quality: staffs tried automatic noisemakers, such as gas cannons and ultrasonic devices, and posted allegedly frightening predator effigies. But the flocks remained. “There’s no magic black box out there,” Cleary says. “What we have got to do at any airport is determine why the animals are there and take measures to eliminate what is attracting them.”
So in 1991 the FAA brought in the U.S. Department of Agriculture’s Wildlife Services Program, the branch of the government assigned to deal with wildlife-human conflicts. “We found that a lot of technological approaches have to be used intelligently and judiciously—and sparingly,” says program head Richard A. Dolbeer. What works, they have found through tests at the Wildlife Service’s research station near Sandusky, Ohio, is a multipronged assault designed to make the airport unattractive to birds. Measures include minimizing open water near runway ends, closing nearby garbage dumps and removing other food sources such as insects (through pesticides), setting off random explosions from fireworks and gas cannons, and even reintroducing predators, such as trained falcons and dogs, and allowing professional biologists armed with shotguns and permits to bag a limited number of the federally protected avians. The approach seems to work: New York’s JFK, which in 1988 reported more bird strikes than any other U.S. airport—300—has reduced that number by 75 percent.
To eliminate the risk entirely, some researchers have not given up hope for the magic black box to shoo birds away. Jim Genova of the Washington, D.C.– based Defense Research Associates is working on a project based on research begun in the 1960s by biophysicist A. H. Frey. Following up on reports that people could hear radar, Frey found that his graduate students could accurately “hear” information coming out of microwave transmitters. (The students also reported headaches afterward.) Theorizing that the microwaves caused pulses of heat in the brain, which in turn expanded and contracted the cochlea, Genova set out to try sending a microwave alarm to birds.
At the Sandusky facility in 1997, he and his colleagues mounted a microwave transmitter on a truck and sent it barreling toward a cage of wild birds. When 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 off. Genova says that tweaking the pulses sent out by a common aircraft transmitter called a DME (for distance-measuring equipment), he can turn a ubiquitous aircraft instrument into an warning siren for wildlife.
Not everyone is as enthusiastic as Genova. “The jury is still out,” says the FAA’s Cleary. “We are considering trying to put it to rest one way or the other.” Genova plans next spring to mount a modified DME in a small plane and head toward a flock of birds to see if it works. If it doesn’t, the pilot may well have a bigger headache to contend with than the microwave variety.