Less than two years after he and his brother Wilbur pioneered powered flight, Orville Wright became the first pilot to strike a bird in flight. The date was September 7, 1905, near Dayton, and the bird was probably a red-winged blackbird. Since then, collisions between wildlife and aircraft have increased dramatically, with 82,057 strikes reported in the U.S. between 1990 and 2007.
The Hudson River landing of US Airways Flight 1549 last January has helped focus worldwide attention on the wildlife strike problem, with a flurry of news articles, forums, seminars and overall increased public awareness of the issue.
Globally, wildlife strikes have killed at least 219 people and destroyed more than 200 aircraft. In the U.S., the vast majority of reported aircraft-wildlife collisions involve birds (97.5 percent), followed by terrestrial mammals (2.1 percent), bats (0.3 percent) and reptiles (0.1 percent). A significant percentage of wildlife strikes involve general aviation aircraft, including the 1973 fatal crash of a Learjet 24 on departure from Atlanta’s DeKalb-Peachtree Airport (PDK). The plane struck a flock of brown-headed cowbirds that were attracted to a nearby trash disposal facility, prompting the Federal Aviation Administration (FAA) to issue guidelines for the location of solid-waste disposal facilities on or near airports.
NBAA’s Jeff Gilley, director for airports & ground infrastructure, says that preventing wildlife strikes is directly related to proper zoning and compatible land uses at airports. Through its regional representatives across the country, the Association monitors airport compliance with FAA wildlife regulations and guidance. In addition, there are a number of non-FAA federal rules, regulations and permits that affect land use and wildlife control at airports, as well as state and local laws and ordinances.
“Any airport that receives federal funds has obligations triggered by their sponsor assurances agreement,” says Gilley, noting that these include the responsibility to ensure a safe operating environment and assess the risk and magnitude of the wildlife strikes at their airport. Based on assessed risk, airports may need to devise a wildlife hazard management plan for reducing strike risks at their facility.
In fact, airports around the country are taking a variety of actions to mitigate wildlife and bird strikes. Airports near large bodies of water or surrounded by wetlands have different challenges than those near wooded, unpopulated areas or those surrounded by urban development. Pyrotechnics, wildlife capture, underground holding tanks, dog patrols, special fencing and a new avian radar are among the tools airports are using to keep wildlife off runways and away from climb-out paths.
Airports Employ Preventive Measures
At Southwest Florida International Airport (RSW), border collies have been chasing away the airport’s large populations of wading birds – egrets, ibis and sandhill cranes – since 1999. According to Bobby Orick, RSW’s senior manager of operations, the collie will “clean the airfield off” first thing in the morning, and then sweep the area a couple more times during the day to scare away the large birds. “This has worked very well for us,” says Orick, who adds that the airport also uses other wildlife mitigation tools, such as pyrotechnics and weed control.
Missouri’s Spirit of St. Louis Airport (SUS) had a wildlife problem due to wetlands located on the south side of the airport, less than 1,000 feet from the main runway.
Flocking birds, deer, coyote, skunk and other wildlife were frequent visitors. When the airport decided to mitigate the wildlife problem, they worked with local conservation agencies and actually moved the wetlands to a large area far to the west of the airport.
Ingeniously, the former wetlands were then turned into an 18-hole golf course, which also serves as the master drainage facility for SUS. Dave Schubert, airport operations manager, says that the airport even makes money through its lease with the golf course. And rather than reintroducing a bird and wildlife problem by storing above ground the water needed to maintain the course, “we invested in huge underground flexible bladders for the golf course,” says Schubert.
To aid in the visual observations of potential bird strikes, an avian radar system has been undergoing testing at Seattle-Tacoma International Airport (SEA) for several years and will soon be deployed for additional testing at several other air carrier airports. Experts say that the technology can help with wildlife management and control as well as airport safety management, but the FAA also is considering several kinds of radar systems and other wildlife/bird strike prevention technologies such as bi-static radar, an active dispersal system, aircraft lighting and sound, acoustic deterrents and more.
Finally, in order to disseminate research and data on bird strikes, Embry-Riddle Aeronautical University recently launched the International Center for Aviation and Wildlife Risk Mitigation. The center will serve as a clearinghouse for information on the subject, including successful strategies to mitigate the threat.
How to Reduce the Risk of Wildlife Strikes
Although wildlife strike prevention is most effectively accomplished on the ground, experts say there are some precautions that operators can take:
- Be vigilant during takeoff: Of reported strikes with turbine powered aircraft, 93 percent occur at less than 500 feet AGL; 90 percent of strikes occur at or below 100 feet AGL. Above 500 feet AGL, the risk of a bird strike declines 32 percent for every 1,000 feet.
- Keep departure airspeed at or below 250 knots at altitudes below 10,000 feet: The kinetic energy of a bird is 31 percent greater at 300 knots than at 250 knots. Some experts suggest maximizing climb rate through 3,500 feet, especially at night in the months of April to May and September through November.
- Increase the visibility of your aircraft: Although there is no definitive data, experts say that it can’t hurt to make the aircraft as visible as possible. For example, keep exterior lights on when in the airport environment.
- Report wildlife strikes and get familiar with the FAA’s Online Strike Database: A recent proposed rule by the FAA to prevent public access to its wildlife strike database (wildlife-mitigation.tc.faa.gov) was struck down, and the web site is now more user-friendly than ever, with a wealth of information, research and news.