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Birds and aircraft: a risky combination

We've all seen lists itemizing the more dangerous professions: firefighter, police officer, coal miner, construction worker, underwater welder, etc. But virtually any line of work - or play for that matter - involves accepting a certain level of risk. With over 25 years of aviation experience and many thousands of hours of flying time in both the military and civilian worlds, I've been exposed to a few tense moments. Most risk is mitigated through proper training, well-maintained aircraft and experience. But one potential hazard keeps me alert these days and it comes from a seemingly innocuous source: birds.

Just this spring I hit a gull on takeoff from a southern Minnesota airport. It moderately dented the wing and the bird's ribs tore into our pneumatic deicing boots prompting the airplane to be grounded until fixed.

I doubt there is an aviator out there with any significant flying time that hasn't, at one time or another, hit a bird with his or her aircraft. Most encounters are harmless (to the aircraft, not the bird) but the potential is there for bad things to happen. To illustrate, a close friend of mine was piloting a B-1 bomber some years ago when it hit an American white pelican while flying along a low-level route in Colorado. Tragically, three lives were lost in this particular incident as well as a multi-million dollar aircraft. The threat from our feathered friends is very real.

Birds, especially large ones like waterfowl and gulls, present a number of hazards to aircraft. Ingesting birds into an engine has the potential to destroy it or severely restrict its usefulness. Large birds hitting an aircraft's tail or wing can disrupt the normal airflow over the surface creating difficult aerodynamic issues. And birds striking the windscreen have broken through the glass, making life miserable for flyers.

Since people first started flying heavier-than-air machinery over 100 years ago, there have been collisions with birds. With ever faster aircraft, however, the danger ante is upped. One, faster machines mean less time for aviators to react to a threat. And two, higher speeds lead to much more potential damage to aircraft. It's a function of the old energy equation: mass times velocity squared. (Example, a Canada Goose weighing 12 pounds struck at 150 m.p.h. generates the equivalent energy of 1,000 pounds dropped from 10 feet). Add to that the dramatic increase in the number of airplanes in the sky and it's easy to grasp the statistics.

According to the Institute for Information Technology Applications located at the Air Force Academy in Colorado Springs, Colo., there have been over 120 aircraft destroyed worldwide by bird strikes since 1990, including 147 fatalities. The Federal Aviation Administration (FAA) reports an average of over 6,000 reported bird strikes yearly in the U.S. alone. However, it is estimated 80% of strikes are not reported since it isn't mandatory to do so. Dollar losses are eye-opening: An estimated $.0.5 billion per year in direct and indirect costs. And that's just civilian aviation in the U.S. alone.

Most collisions, as one may imagine, take place near the ground during takeoffs and landings. Obviously, this becomes a challenge for airports. Shawn Dobberstein, Hector Airport's executive director, said a number of tools are in place to help minimize the risk. "In conjunction with air traffic control and pilot reports, our staff continuously monitors bird activity on or immediately adjacent to the airfield," said Dobberstein. He said pyrotechnics and other devices are used to steer birds away from the airport. And grass height is precisely monitored to dissuade certain birds from landing.

This column is not meant to alarm airplane travelers; its purpose is merely to point out that, like most anything in life, there are inherent risks in the aviation business. We continue to better understand migration patterns and habits of birds. Research is ongoing to find ways to address the threat avifauna present to aircraft. New approaches are emerging, including new bird detection radars and more effective use of current Doppler radar. But given the thousands of airports around the country and the ever-growing number of airplanes using them, we will likely never be completely free of the potential hazard presented by birdlife.