In an era of acute concern about airline safety, on most days Northwest Airlines pilot Paul Eschenfelder is forced to give more attention to stray starlings than the unlikely threat of a terrorist bomb.
"Birdstrikes" don't get much publicity. In fact, pilots have no instructions in their manuals on what to do if a bird crosses their path. But collisions with birds are a common threat that, until now, have attracted little attention.
Just last week, a Delta 737 was forced to make an emergency landing at Boston's Logan International Airport because one engine ingested a bird shortly after takeoff. The plane was grounded for repairs, but none of the 59 passengers was hurt.
The incident highlighted why more than 300 aviation industry representatives from around the world met at Logan this past week to discuss bird-management techniques at America's airports.
The threat of a birdstrike is considered more serious than ever, in part because programs designed to protect wildlife have worked, dramatically boosting populations of many birds in the US. That rebound comes at a time when airplane manufacturers are prone to promote two-engine - rather than four-engine - planes, like the new Boeing 777.
The US military is particularly concerned. Four major birdstrike crashes have occurred in the past two years, including an Air Force AWACS plane in which all 24 crew members were killed.
Commercial-jet windshields and engines have been beefed up to protect against collisions with fowl, but no one has found a way to completely bird-proof an aircraft. Some 4,500 birdstrikes are still reported yearly by commercial and military aircraft, causing about $250 million in damages.
"If you [hit] a 10-pound Canada goose on liftoff or landing, it's the equivalent of 1,000 pounds dropped 10 feet," says Richard Dobeer, a biologist at the US Department of Agriculture's Wildlife Research Center in Sandusky, Ohio. "It's impossible to design an engine to withstand that kind of damage."
That's why efforts to manage bird populations at airports are so important, says Dr. Dobeer. Several countries, as well one airport in the US, shared their successes at the conference. "It's a complex endeavor," says Dobeer.
MANY airports are located near wetlands, where federally protected birds proliferate. Gulls are the most serious problem; next is waterfowl - especially geese; then blackbirds and starlings.
Because many of these birds are protected, the emphasis is on nonlethal ways of solving the problem. An integrated program works the best, Dobeer says, because birds adapt to some methods of control.
New York's John F. Kennedy International Airport is considered a model of the multifaceted approach. In the late 1980s, Kennedy topped the list of reported birdstrikes in the US, with some 300 per year. It has cut that number by about 75 percent, according to Lanny Rider, manager of aerospace operations for the Port Authority of New York/New Jersey. But the numbers are slightly up again this year.
Spending about $500,000 annually, Mr. Rider says the program at Kennedy focuses on the biggest threat - gulls - but also maintains an overall strategy because birds tend to return. His tactics include:
* Runway patrols that fire shotguns with loud shellcrackers, propane cannons, and tape recordings of different species of birds making distress calls.
* Tall grass. Geese feed on grass, but do not like it tall.
* Use of falcons to patrol the airspace. Several other countries, notably Scotland, have used this method successfully. Kennedy is experimenting with having falconers on the field from sunrise to dusk. Periodically, bird owners fly the falcons - predators to smaller birds - over the airport to scare away other species.
* Spraying insecticides several times per year. Gulls feed on insects.
* Shooting limited numbers of gulls and starlings, after obtaining a permit from the US Fish and Wildlife Service.
* Cleaning up garbage and covering dumpsters. Taxicab drivers are asked not to feed gulls. Rider's staff also succeeded in getting two landfills near Kennedy closed.
Canada had a "very serious [birdstrike] problem at several airports," says Bruce MacKinnon, a specialist in wildlife control with Canada Transport. Pilots at the conference were poring over a comprehensive Canadian manual for airports and pilots on dealing with birds.
But US pilots say they still lack scientific research on how birds behave when confronted with aircraft and what pilots should do when they encounter birds. "Some pilots turn their radar on when they run into birds, or descend rapidly," says United Airlines pilot George Gil. "But that probably has no effect."
"One new thing I heard here," Captain Gil says, "is that pilots should pull up, rather than descend, because birds naturally dive."