Making Airspace for Birds and Planes
When birds and aircraft collide, it can be disastrous. Fortunately, a combination of common sense, cutting-edge technology, and a bit of bird knowledge is making the skies safer for all.
Those who work in the specialized field of birdstrike avoidance have spoken out for years about the rising hazard of airplanes hitting birds. "The numbers keep going up, and the FAA [Federal Aviation Administration] is just clueless," Paul Eschenfelder, a veteran pilot for a major international airline, told me late last year. "The airline industry doesn't want to get involved because they're afraid they might have to spend money. Nobody will get involved until we have a big catastrophe."
The big catastrophe nearly came on January 15, 2009.
About 90 seconds after takeoff from New York's LaGuardia Airport, US Airways Flight 1549 struck a flock of Canada geese, disabling both engines. "It was the worst sickening, pit-of-your-stomach, falling-through-the-floor feeling I've ever felt in my life," Captain Chesley Sullenberger would later tell CBS's 60 Minutes. The plane didn't have enough altitude to glide back to LaGuardia, so Sullenberger executed an emergency water landing on the Hudson River. He and the crew helped all 155 people on board get off safely.
While the accident brought the dangers of birdstrikes to the nation's attention, experts have long been investigating the most effective ways to curtail such collisions. They've discovered it requires an ornithologist's knowledge of bird behavior, high-tech radar equipment, labor-intensive ground observation, and some old-fashioned wildlife detective work.
On a morning last December in Tulsa, members of the 138th Fighter Wing of the Oklahoma Air National Guard filtered into a conference room for a 9 a.m. presentation. The fighter pilots wore green flight suits. Shoulder patches identified them as members of the Tulsa Vipers F-16 squadron recently returned from Iraq. They had the look of Top Guns expecting to endure a time waster taught by a civilian. A civilian bird guy.
The presenter that morning was Russ DeFusco, a leading authority on birdstrikes. His job is to keep gulls, starlings, and turkey vultures from getting sucked into the Vipers' engines. To a fighter pilot just back from combat, though, Canada geese may be low on the list of concerns. "These guys are worried about dodging bullets, not birds," DeFusco told me, "so I've got to get their attention in a hurry."
To do that, he told this story.
In July 1995 DeFusco gave a similar briefing to officials at Elmendorf Air Force Base outside Anchorage, Alaska. Elmendorf had a notorious Canada geese problem. Migrating flocks liked to rest and feed on the grass surrounding the base's runways. "You've got to watch the runway grass carefully, and do everything in your power to harass that first migrating bird away from here," DeFusco told Elmendorf officials. "If he lands and feeds, that sends a signal to the rest of the flock. One bird will draw dozens and then hundreds of others."
When DeFusco delivered a plan for an aggressive bird management program, the officials put a few suggestions into action but ignored most of the recommendations. Two months later, on September 22, an Air Force AWACS communication plane struck 25 Canada geese during takeoff. The birds knocked out the two left engines, sending the plane out of control. It crashed in heavy woods outside of Anchorage, destroying the plane and killing all 24 crew members aboard.
If the pilots in Tulsa thought their nimble fighter jets made them less vulnerable, DeFusco told them, they should think again. "The Air Force has lost more F-16s to birdstrikes than any other aircraft," he said. Twenty-two years ago DeFusco was hired to investigate an F-4 fighter destroyed by a griffon vulture in Spain. "It turned out the bird crashed straight through the canopy and decapitated the pilot. The bird goo blinded the co-pilot, who went down with the ship. When they found the co-pilot's body his hand was still gripping the stick."
Birds collide with airplanes, on average, about 20 times a day around the United States. The results of these midair meetings are fairly predictable. The birds end up as "snarge," the industry term for the gooey remains. Commercial jets usually escape with little damage. But not always. A bird can crumple an airplane's nose cone, punch a hole in a wing, disable the ground steering, or destroy an engine. "Most times they just bounce off, and you don't even know you've hit a bird," says Eschenfelder, a member of Bird Strike Committee USA, a group of aviation industry officials who track the issue. "But a jet engine can't just swallow those things and keep going. It's a real hazard, and it's happening every day."
And it's getting worse. The airline industry doesn't publicize it--for obvious reasons--but more birds are hitting more airplanes every year. According to the U.S. Department of Agriculture and the FAA, which monitor wildlife hazards to aviation, there were 1,759 reported birdstrikes to civil aircraft in 1990. In 2007 there were 7,666--a fourfold increase. Some of that can be attributed to better reporting by pilots and mechanics, although the FAA estimates that only 20 percent of all strikes are reported. Another reason for the increase might be the swelling number of flights; commercial air traffic has increased by 1.8 percent a year since 1980, and there were more than 28 million flights in 2007. The FAA estimates that number will continue growing by 2 percent a year and will reach 36 million flights by 2020. Another key indicator is a statistic known as strikes per 10,000 movements of aircraft. It's like the industry's birdstrike batting average. In 1990 it was 0.53, or one strike for every 20,000 flights. By 2007 it had tripled, to 1.75.
Despite the rising incidence and the example of US Airways 1549, the issue remains a low priority for commercial airlines and the FAA. The Air Force has long made birdstrike reporting mandatory. For civil aircraft under FAA jurisdiction, though, reporting remains voluntary. "We're always looking at ways to improve our wildlife mitigation efforts," says FAA spokesperson Hank Price. But in the weeks following the US Airways crash, the agency took no action to review its existing avoidance procedures. "The shame of it is, this is something we can have some control over," says Eschenfelder.
While the continued decline of songbirds and at-risk species is well known, populations of gulls and turkey vultures--large birds capable of inflicting a lot of damage to an airplane--have risen steadily, and grassy fields and retention ponds surrounding airports are attractive feeding and resting grounds for Canada geese. "There are a lot more big birds than there were 40 years ago, and they're hitting aircraft with greater frequency," Steve Predmore, chief safety officer of JetBlue Airways, told a gathering of industry experts in 2006. "Birdstrikes are a real threat," he said, with no silver bullet solution.
There may be no silver bullet, but the nation's pilots and air travelers do have a Lone Ranger. DeFusco realized his calling in the early 1980s when, as an Air Force Academy lieutenant, he hit a bird on his second solo flight. As flames shot out his engine, DeFusco landed the plane and walked away. Because of the high speed, pilots usually see just a flash before impact, if they see anything at all. But DeFusco was a lifelong birder. "It was a Mississippi kite," he recalls.
DeFusco worked on the Air Force's BASH (Bird Aircraft Strike Hazard) team in the late 1980s and 1990s, developing the first radar-based system for bird avoidance before leaving to become an independent consultant. Today he works out of a home office in Colorado Springs, but he's in such demand that he travels three days a week. "Anybody who has this problem eventually finds me," DeFusco says. "And right now a lot of people are finding me."
Solving human-bird conflicts in a high-risk environment like airports involves a blend of cutting-edge surveillance and traditional birding knowledge. Major airports have employed wildlife managers since the 1970s, and yet the number of birdstrikes continues to rise. Now, DeFusco believes, the aviation industry needs to stop thinking of birds as nuisances and start thinking of them as a natural phenomenon--like the weather. "We're integrating bird migration patterns and historical data into models that will let us predict when and where birds will be concentrated," he says. "Where we are with birds today is something like where we were with weather forecasting 50 years ago."
At work DeFusco combines a detective's gumshoe sleuthing with a lobbyist's persuasive diplomacy. The Tulsa job was part of a long-term contract with the Air National Guard. After the 1995 crash at Elmendorf, military officials demanded new birdstrike avoidance plans at each of the nation's 88 Air National Guard bases. DeFusco has been creating those plans since 2001--after Tulsa he'd have only four more to go.
Like a private eye looking for clues, DeFusco walked the grounds, climbed into the air traffic control tower, chatted up the maintenance crew, and poked around corners in the F-16 hangar. He sought out any natural or built feature that would attract a bird or let deer or coyotes slip through the perimeter fence. (Airplanes hit about 150 mammals, mostly deer, on American runways every year.)
"I often start with the grass," DeFusco told Lt. Col. Jimmy Nichols as they stood at the edge of the Tulsa Airport perimeter road. "Your grass here is in nice shape, not a lot of weeds, which is good. Except for Canada geese, grass is indigestible to most wildlife. The thing is, right now it's cut too low. You want it seven to fourteen inches high. If grass grows above a bird's eye height, you obscure their interflock communication system and keep them from seeing predators. It makes 'em real nervous."
Nichols made a note of it. As the 138th Fighter Wing's safety officer, he's responsible for keeping birds out of his pilots' airspace. And as a fighter pilot with nearly 20 years' experience, he wants nothing to do with birdstrikes. "I once hit a turkey vulture on a low-level flight outside Phoenix," he said. "The bird guts and feathers splattered inside the cockpit. The smell--oh, man. That's nothing I want to experience again."
DeFusco nodded in sympathy. "Gulls are the birds most often struck by commercial airliners, but turkey vultures are the number one species for significant mishaps," he said. "We've lost more military aircraft to them than any other bird." A combination of factors is at work. They're big birds--each weighs about four pounds. There are a lot of them, and they hang out in circular soaring patterns at 2,500 feet. "They've got a locking mechanism in their wings, so they're actually conserving energy soaring up there," said DeFusco. "And they've got no airborne predators, so they haven't developed an evasive response. When an aircraft comes at a red-tailed hawk, the hawk will dive. The turkey vulture doesn't know enough to get out of the way."
Some oak trees caught DeFusco's eye. Airport officials know that trees provide birds with shelter and food, but the Tulsa mayor likes them. DeFusco suggested pruning to let the wind pass through. "Birds roost there for the thermal cover," he said. "If you take that away, they'll look for other trees away from the runway. You lose the birds, the mayor keeps his trees."
DeFusco stepped inside a hangar, where mechanics were busy stripping down the nose of an F-16. Some bird droppings on the floor caught his eye. "That's from our local red-tail," one of the mechanics told him.
Allowing red-tailed hawks to reside at airports is a relatively new and still controversial strategy. In theory, the predatory birds discourage other birds from coming into the area. The data seem to confirm it. Officials at Seattle-Tacoma International Airport, for instance, have allowed six pairs of red-tails to nest nearby since 2001. "The resident hawks are airport savvy," says Steve Osmek, Sea-Tac's wildlife program manager. "The birds that tend to get struck are juveniles and migrants--the young and the dumb." The strategy isn't without risk. If a resident hawk caused a mishap, it could be tough to explain in a sound bite why airport officials encouraged their presence.
DeFusco had a simpler solution. "The hawk's okay," he told the hangar crew, "but really, the best thing you can do is close the big hangar doors a half-hour before sunrise and a half-hour before sunset, when smaller birds are coming home to roost."
Habitat management--grass, trees, hangar doors--is the low-tech part of DeFusco's job, and it's an easy sell to airport officials. The high-tech part is tougher. It's one thing to cut the grass higher. It's another thing entirely to convince air traffic controllers to start thinking of birds like they think of weather.
The concept, DeFusco explains, goes back to the National Weather Service's nationwide rollout of Doppler weather radar in the 1990s. The NEXRAD system--TV weathercasters use it for "your Doppler radar forecast!"--is so sensitive that it picks up flying birds, which are noise in the signal for meteorologists. "Their trash was our treasure," says DeFusco. "We could remove the weather from the signal, and what remained was birds. It was a huge breakthrough."
Using data from National Audubon's Christmas Bird Count, the U.S. Geological Survey's Breeding Bird Survey, and historical birdstrike records, the Air Force team created a database of bird traffic around the country. Real-time Doppler radar provided a secondary layer of information about current bird activity in the area. At the Air Force's Avian Hazard Advisory System (AHAS), pilots combine the two systems to determine the "bird weather" along their route. "From a pilot's perspective," says DeFusco, "the AHAS system is a measure of the amount of meat in the air in front of your airplane."
Among birders, for instance, the Skagit Valley north of Seattle is a well-known wintering ground for snow geese, trumpeter swans, and bald eagles--big birds that can bring down a small plane. Pilots may know nothing about the valley's birding reputation, but a glance at the AHAS site lets them know the area's birdstrike risk level is severe during late December.
Pilots, airfield managers, and air traffic controllers don't universally embrace the AHAS system, mainly because it represents one more piece of data they've got to think about. DeFusco was sensitive to the problem. "This isn't meant to keep you from flying," he assured the F-16 pilots in Tulsa. "It's like a weather condition--if you know a storm is coming in, that won't necessarily ground you, but you might alter your route to avoid it."
The military uses the AHAS system, but civilian airport officials have been slower to adopt it. "It's a challenge Russ and I have talked about for years," says Ron Merritt, president of DeTect, a company that specializes in aviation radar systems. "How do you get bird information to flight crews? There's no bird guy in the [air traffic control] tower. One way to think about it is like wind shear," he says, referring to the weather hazard responsible for a number of fatal crashes in the 1980s. Wind shear problems were reduced in the 1990s with the development of NEXRAD. "Years ago the FAA got serious about wind shear and implemented a system in some airports where a wind shear advisory light dings in the tower when conditions are dangerous. We'd like to do something similar for birds. When there's a swallow storm out there, nobody wants to fly into it."
In Tulsa, Russ DeFusco made the toughest sales call of the day: the air traffic control tower. This was the job's diplomatic end. Everybody else at the airport and Air National Guard base could be gung-ho about birdstrike prevention, but if the people in the control tower weren't on board, all of DeFusco's work might be for naught. He wanted the air traffic controllers to start integrating real-time bird hazard information (that is, pilots and airfield managers spotting flocks of birds near the runway) into their communications with pilots. "If the [bird hazard] level is severe, they should let pilots in the area know that," he said in the elevator up to the control tower. "But they've got strict union rules, and sometimes that stops the whole thing cold."
One supervisor and two controllers worked the tower. It was a slow day, and they could afford to listen to DeFusco's pitch. Below the tower two dozen mallards, buffleheads, and gadwalls paddled around a stormwater retention pond. "We want to make it easy for you," he told the controllers. They listened politely, but their faces read skeptical. On the way out, the tower supervisor gave DeFusco a few encouraging words. "I think we can do it," he said. "We've just got to make sure it's not against any of our rules."
The next morning DeFusco wrapped up his work with a briefing for the 138th Fighter Wing commander, Col. Michael Hepner. DeFusco had been up late the previous night preparing a PowerPoint presentation. He pitched the utility of the AHAS avian radar system, and mentioned the air traffic controllers' crucial role with diplomacy and tact. Hepner nodded in a way that conveyed his understanding of both the importance of the technology and the difficulty of changing air traffic control protocols.
At the end of the day, DeFusco felt he had made some converts to the cause. The air traffic controllers might not fully support it yet, but DeFusco was confident that the 138th Fighter Wing's safety officer, Lt. Col. Jimmy Nichols, would continue to press the issue long after DeFusco's report was filed away. "There's nothing like experience to bring the importance of this issue home," DeFusco says. "When you hit a turkey vulture going 500 knots, like Colonel Nichols did, you'll go out of your way to avoid a repeat performance."
This article originally ran in the September-October 2008 issue as, "Clearing the Air."
No single technique will always keep birds out of flight paths, so airports use a variety of strategies. The cheapest option? "The human being out there hooting and hollering," says John Ostrom, chair of Bird Strike Committee USA. "If you want to move birds, 'shoo, shoo, shoo' still works." Here are other popular tools:
Gas cannons Essentially propane ignited to make a loud noise, gas cannons can be set to timers or remotely controlled. At Minneapolis-St. Paul International Airport, they're often used with distress-cry generators, which broadcast digitally recorded bird sounds.
Radar Seattle-Tacoma International Airport has been the primary test site for bird radar since 2006, and it recently installed a third radar system. Other airports, including Chicago's O'Hare and Dallas Fort-Worth in Texas, plan to install bird radar this year.
Pyrotechnics Each day officials at airports nationwide set off everything from bangers and screamers to grenade-launched pyrotechnics to disperse flocks around runways. They're cheap, easy to use, and effective--even against imperturbable Canada geese.
Falcons and dogs Not all solutions are mechanical. New York's John F. Kennedy International has a resident falconer; his handful of predators keeps smaller birds at bay. Southwest Florida International in Fort Myers is one airport that uses border collies to chase unwanted guests off the tarmac.
Paintball Personnel often use paintball guns, which are less pricey than animal programs. For this nonlethal tactic, officials at Minneapolis-St. Paul International Airport aim into and just outside of flocks that don't budge when pyrotechnics are set off.--Katherine Tweed