Aviation's Bird Flu

THE FIRST RECORDED INFLIGHT COLLISION INVOLVING A powered aircraft and a bird is believed to have occurred not too long after the first powered flight. In September 1905, Orville Wright was chasing a flock of birds when he struck one. He landed safely but the encounter was fatal for the bird. The incident, recounted in the Wright Brothers' diaries, began a dangerous relationship that continues to this day, having claimed many hundreds of human lives and countless thousands of birds.

That danger was reemphasized in mid-January in the accident involving US Airways Flight 1549, which ran into a gaggle of Canada geese shortly after taking off from New York LaGuardia, lost both engines and successfully ditched in the Hudson River. It is fair to say, however, that the risk posed by mixing aircraft and birds is never far out of mind even if solutions remain elusive. Today, for a variety of reasons, the risk may be greater than ever, say experts.

"There is no doubt [US 1549] was an accident waiting to happen," warns recently retired US Dept. of Agriculture ornithologist Richard Dolbeer, chairman of Bird Strike Committee USA. "There has been a dramatic increase in bird species, particularly large flocking bird varieties, and in our 1990-2007 database we had 1,000 incidents of direct hits into two engines," he says.

According to BSC-USA data, the cost of venturing into the bird's domain is high. Human fatalities in bird strike-related air crashes number 219 worldwide since 1988, while bird strikes cost US civil aviation more than $650 million a year. Globally that number is $1.2 billion. Many other aircraft have experienced significant damage from strikes and harrowing landings for those onboard.

Testifying to a US congressional committee following the 1549 ditching, FAA Deputy Associate Administrator for Aviation Safety Peggy Gilligan said the agency has collected more than 100,000 voluntary wildlife strike reports since 1990, 85% of them involving commercial aircraft, with the "increasing number of bird strikes a combination of better reporting and increasing bird populations."

When reporting was introduced in the US in 1990, that year saw only 1,900 reports. This had grown to 8,000 in 2008 but the problem is even worse than the numbers indicate, says BSC-USA, with studies showing that only about 20% of bird strikes to passenger aircraft are reported and only 5% of general aviation aircraft strikes.
The pattern is similar in Australia, according to a report from the Australian Transport Safety Bureau released in late 2007. It examined bird strikes from 2002 to 2006 and found that in the five-year period there had been an increase in strike reports from 750 in 2002 to 1,250 in 2006, with a total of 5,103 strikes, 7.5% classified as damaging.

That bird strikes are becoming more frequent is of little surprise to Dolbeer given the increase in bird populations. For instance, the North American nonmigratory Canada goose population increased about fourfold from 1 million in 1990 to more than 3.9 million in 2008. Between 1990 and 2007, more than 1,400 strikes involving Canada geese were reported in the US and more than 40% of the events involved multiple birds. Dolbeer adds that there have been increases in other large birds such as "snow geese, bald eagles, ospreys, sandhill cranes, wild turkey vultures and white pelicans." And these birds are heavyweights with a body weight of 15-20 lb.

The reasons for the spectacular increases, he says, relate to the banning of DDT and similar chlorinated-hydrocarbon insecticides in 1972, an increase in the protection of many species and expansion of a number of wildlife refuges. "In the 1960s the environment was pretty polluted and the measures put in place were obviously a good thing and enabled species to rebound," he notes.

Avian Radar

FAA statistics show that the closer the aircraft is to the runway, the higher the risk of a bird strike, with 73% occurring within the airport environment up to 500 ft. Thus regulators globally have focused bird strike mitigation efforts at and up to 5 mi. from airports. In 2000 FAA began research to determine if low-cost radars can detect birds reliably at or near airports to provide a real-time bird strike advisory system. It is conducting radar evaluations with three Accipiter Avian Radar systems at Seattle-Tacoma International and Chicago O'Hare, three being installed at New York JFK and a possible rollout for LaGuardia and Newark. The program is being carried out by its William J. Hughes Technical Center in Atlantic City and its Center of Excellence for Airport Technology at the University of Illinois at Urbana-Champaign.

Avian radars are not new and have been the subject of research and development for more than 40 years. Airport ASR-9 Doppler surveillance radar and WSR-88D weather radar have been used for bird detection at distances of up to 100 nm. But cost, update rate and resolution have impeded their avian potential for shorter ranges near airports.

Avian radars evolved in the late 1990s using inexpensive X-band and S-band marine radar transceivers developed to track birds and aircraft. Accipiter Radar Technologies CEO and President Tim Nohara says major advances in automatic avian target extraction took place between 2000 and 2005, spurred by the interest of the US military, FAA and Transport Canada. Radar engineering companies Accipiter Radar with Accipiter and DeTect with Merlin entered the market to compete with GeoMarine's development in 2000 of the first automatic vertical scanning MARS radar for bird detection. In Europe, Netherlands-based TNO has developed its Robin Lite bird radar, which has been used to great effect by several air forces in Europe.

Accipiter avian radar systems are in use at numerous US Navy, Marine Corps and USAF airfields as well as in the commercial trials. In those trials, Nohara says the purpose is to "understand what they give you and comprehend their limitations and then move to see how controllers and wildlife experts can use this tool." He sees what he calls the "wildlife management mode" as the here-and-now: "The avian radars are extremely effective in assisting often under-resourced staff in managing habitat, frightening birds off and even advising ATC of a large flock."

Dolbeer agrees wholeheartedly. "Certainly staff could use the radars to record nighttime bird movements and to monitor bird paths, for instance toward some new landfill or water feature in the proximity of the airport."

Nohara is not so sure about the public acceptance of a "sense-and-avoid mode" that would have a cockpit radar display for pilots for use around airports. "There are advocates for this but we can't have pilots making sudden maneuvers in the airport vicinity. I am not certain we want to go there. The airport is an incredibly intricate control system, and if we inject new information to cause some significant changes you must engineer that in order to assess the impact on a system that has evolved into an extraordinary safe environment over many decades." He sees this type of mode for pilots as perhaps "10 years out."

The latest generations of avian radars are able to detect from "insect to aircraft" with reasonable 3D information on position and altitude, direction and speed of each bird/flock track in a 360 degree surveillance radar mode as required by airports. Classification of birds using wing-beat frequency would require a far more restricted target mode.

Airport Experience

At Sea-Tac in cooperation with the University of Illinois, the Accipiter avian radar systems were installed in August 2007. Testifying before the US House subcommittee on aviation on Feb. 24, MD Mark Reis said the airport is using the radars to "confirm that hazardous bird activity is not increasing near the airport's stormwater ponds and to help identify wildlife trends." But, he asked, "How much information do the air traffic controllers and pilots truly need to enhance safety, and what actions if any should [they] take when concentrations of birds are found?"

Avian radar is not yet the "silver bullet," he testified, as it detects too much bird activity, "meaning we need to determine what information is best to pass on immediately to the air traffic controllers. With appropriate information screening, that capability may come." He compared the situation to that of windshear radar, "a technology that took years to perfect."

Taking a contrasting view is Florida-based DeTect, which says advanced bird radars from a number of manufacturers have been deployed tactically by the US military since 2003 and NASA since 2006 with real-time displays. DeTect recently announced the next generation of its Merlin radar, which it says improves its detection of birds through fog and light rain.

CEO Gary Andrews says, "NASA has two Merlin systems it uses to provide real-time detection for space shuttle launches." Detect has delivered over 50 bird radars worldwide including to La Mercy International in Durban.
Andrews says, "About half the radars are in aviation safety, mostly with USAF and NASA, and the other units are derivative technologies where the system is used to manage bird mortality risk at wind farms, as automated bird control systems at industrial sites and by researchers for migratory studies."

Netherlands-based TNO has developed its Robin Lite for civil airports. The radar has evolved from its Robin designed for the military over 20 years, which has resulted in a 50% decline in strikes in that environment.
Senior Project Manager Andy Borst suggests that Robin Lite's ability to identify species is potentially useful as some birds like pelicans and gulls are stupid and may not get out of the way. But he sounds a note of caution on the legal aspects of real-time data, with ATC being in a conflict over takeoff clearance with flocks of birds in the area.

There Is a Light

While airports and regulators grapple with the effectiveness and use of avian radars, airlines can add a significant weapon in the war on birds if the experience of Qantas is any guide.
After a year-long, highly successful trial, it is installing Bend, Ore.-based Precise Flight's Pulselite on its 737-800 and -400 fleets as well as its Q400s. Pulselite is a hardware addition, the size of a typical CD burner, which pulses the aircraft's landing lights approximately 45 times per min. Originally designed as a "be seen and avoid strategy" for GA aircraft, Pulselite-equipped planes can be seen at more than 40 nm. during the day. The system can be linked to TCAS and will activate on a traffic advisory if the pilot has the aircraft's strobe lights selected.

Qantas conducted an extensive evaluation of Pulselite from January 2005 to August 2007 and found a 40% reduction in strikes for the 737-400 fleet and a massive 66% reduction for the -800 fleet. That variation is explained by a more intense landing light configuration for the -800, says Precise Flight Australian representative Peter Reardon. According to QF Boeing Technical Pilot Alex Passerini, the system "has shown a positive trend in reducing bird strikes and has a host of other advantages."

The 737 trial, which now has turned into a 737 fleetwide commitment, followed similar experience with the Dash 8-300 fleet, where installation of Pulselite resulted in a bird strike reduction of approximately 50%. The fleet was averaging 3.65 strikes/aircraft/year prior to the evaluation and 1.83 with Pulselite. QF's success has resulted in orders from Air Pacific, Air Vanuatu and Jet Connect for 737s and Air Nelson for its Q400s. Horizon Air was the first US airline to install the system after a serious bird strike in 2003.

According to Reardon, a former air safety investigator and air safety consultant, a bonus of the system is that the life of landing lights, which do not run as hot because they pulse, has increased by 300%. Qantas has applied Pulselite to its vertical stabilizer logo lights on the -800 fleet as a runway incursion defense strategy. Its experience is starting to gain traction in the US and elsewhere as it talks with its associate airlines, says Precise Flight VP Scott Philiben, who adds, "they are our shining light!"

Another interested airline is Ryanair, says Philiben. The LCC's attention was sparked by a serious accident last Nov. 10 when one of its 737-800s with 177 aboard struggled to a "landing" that collapsed its left main landing gear when both engines lost virtually all power after ingesting starlings that engulfed it at about 200 ft. on final to Rome Ciampino. There were 90 starling impacts to the 737's nose, wings and engines and it was written off.

Philiben explains that it is the spectral color change of the pulsed light that gets the bird's attention--particularly in low-light conditions, the worst time for bird strikes. "It's the incandescent change from the bright to reddish orange they pick up on," he explains. Pulselite is clearly most effective at night and he notes that bird strikes are 7.2 times more likely to occur at night than in daylight between 500 and 3,500 ft. above the runway, which is where 30% of substantial damage is done owing to the greater speed of the aircraft.

The Pulselite work is positive, says Dolbeer. "I am really excited about what Qantas is doing. We are working with Precise Flight examining more cycling of the light pulse and also adding the ultraviolet light spectrum." Ultraviolet paint for parts of aircraft is also a possibility, he says.

Seeing and Hearing

Dolbeer raises some fascinating but simple facts about the relationship between birds and planes: "Most birds aren't suicidal and they will get out of the way if they can see or hear an aircraft." But aircraft are much quieter these days, so "birds can't hear an aircraft approaching," particularly in the landing phase. Studies have shown that aircraft powered by the noisy engines from the 1960s had far fewer bird strikes, he says, pointing out that most aircraft had four engines and "now most have just two."

He laments that there is a major disconnect between biologists and the aviation industry. "What we need is a more robust reporting system as we cannot solve the problem unless it is better defined." There is also a significant lack of understanding about birds, he says. "We need more training of pilots and air traffic controllers about the habits of birds. For example, when faced with an encounter, birds will always dive to get out of the way--they use gravity."

Tragically, many hull losses are caused by strikes when the birds are already on the runway before the takeoff roll starts, says Dolbeer. "Birds always face into the wind when they are on the ground and aircraft take off and land into the wind so the birds can't see the aircraft coming. Pilots and ATC just assume that birds would fly away. Well, the birds will not fly away!"