The vice president of Bend, Ore.-based Precise Flight last month expressed disappointment with Peggy Gilligan, the FAA’s Associate Administrator for Aviation Safety, for failing to acknowledge the effectiveness of “on-aircraft” devices in deterring birdstrikes.
According to Scott Philiben, Gilligan’s February 29 testimony before the House of Representatives’ aviation subcommittee “highlighted strategies exclusive to the airport environment; our research has concentrated in on-airplane-based deterrent systems that would apply to both the airport and non-airport environments, and which would have been applicable to the strike that grounded Flight 1549, which occurred well outside the airport boundary.” On January 15, the pilots of US Airways Flight 1549 were forced to land an Airbus 320 in the Hudson River following a birdstrike that caused both engines to fail.
In her testimony, Gilligan referenced the FAA’s use of wildlife-mitigation techniques, including habitat modification and wildlife harassment tools such as air guns, lasers, dogs, wildlife patrols, trapping and extermination. She also testified that the FAA is investing in the use of bird radars to develop an airport birdstrike advisory system that would detect birds within three to five miles of an airport.
“Bird-detection radar may have the most promise as tools to help airport operators manage their wildlife control programs,” Gilligan said, adding that the agency is conducting radar evaluations at Seattle-Tacoma International Airport, Naval Air Station Whidbey Island in Oak Harbor, Wash., and Vancouver International Airport.
However, Philiben questioned the effectiveness of bird radars. “Birds don’t behave consistently,” he said. “They change direction on a whim for no apparent reason.” So even if the radar detects them, there’s no guarantee that the flock will continue in one direction, he said.
However, radar data has shown that birds scatter when they see an approaching aircraft; therefore, some researchers have suggested that it might be more effective to make aircraft more visible to the birds, rather than simply tracking the birds’ position, Philiben said.
Precise Flight developed its on-aircraft pulsing light system (Pulselite) to enhance safety by making aircraft more visible to other aircraft. To their surprise, some operators started reporting a decrease in the number of birdstrikes after installing the lights.
Precise Flight contacted the USDA’s National Wildlife Re-search Center and agreed to fund studies to confirm the operators’ reports. The studies found that 91 to 99 percent of birds “exhibited alert behavior” when exposed to incandescent pulsing lights.
The tests also showed that the pulsing lights were most effective in low-light conditions, such as cloudy days, nighttime, dusk and dawn. “A spectrum change of yellow to red is ideal in low-light conditions, which corresponds to peak bird activity times,” Philiben said. Aircraft are 60 percent more likely to hit a bird at night and have a 30 percent less chance of hitting a bird with every 1,000-foot increase in altitude.
As a result of these tests, wildlife researchers have theorized that the pulsing lights provide a frame of reference, a sense of movement and direction that gives the birds a better sense of the aircraft’s position. Philiben explained, “If they are warned of potential danger with sufficient time to react, they will get out of the way.”
QantasLink, Qantas Airlines’ regional carrier, agreed to conduct tests using the Pulselite system on a small number of DHC8-300 aircraft and saw birdstrikes reduced by nearly 50 percent. “The results were so compelling that the Qantas main airline decided to conduct similar tests on the 737 fleet,” Philiben said.
The research has also attracted the attention of business aviation manufacturers. Precise Flight is in the process of developing and certifying a special light system specifically for the G650. “Gulfstream is the only aircraft company at present to recognize the benefit of on-board birdstrike mitigation,” Philiben said.
The recognition of the effectiveness of the pulsing light system is important, Philiben said, especially since birdstrikes are increasing in frequency. Between January 1990 and August 2008, the FAA logged 106,604 wildlife and birdstrike reports. The number of annual strikes increased from 1,900 in January 1990 to nearly 8,000 in 2007. There is some evidence to suggest that the increase in birdstrikes is a result of efforts to reduce aircraft noise, Philiben said. A Swedish report found that as noise levels at airports decrease, the number of birds in the surrounding woodlands increases.
The FAA has approved and certified the Pulselite system for nearly all corporate, general aviation, rotorcraft and commercial aircraft, Philiben said.