by Whit Gibbons

March 17, 2003

The goal of an organization named BASH and a research program called BAM is to preserve "war fighting capabilities through the reduction of wildlife hazards to aircraft operations." Travis DeVault of Purdue University introduced me to the generalities of the program several months ago in relation to his research on big birds that can cause big problems for airplanes. In short, the Bird/Wildlife Aircraft Strike Hazard (BASH) is a team of wildlife biologists and other scientists associated with the U.S. Air Force who are attempting to reduce the problems that wildlife, especially birds, cause to military aircraft.

During peacetime we generally think of airplane crashes in regard to weather or technical problems associated with the plane itself. During military conflicts, we of course think first of combat actions. But the impact on aircraft from collisions with birds has become a matter of concern year round, during war or peace. According to BASH records at Kirtland Air Force Base in New Mexico, more than 52,000 bird/military aircraft collisions were documented from 1985 through 2002 (that's more than 7 a day for 18 years). Since 1973 birds colliding with airplanes have killed 35 aviators and destroyed 32 aircraft. The repair or replacement costs for damaged aircraft from bird strikes averages more than $30 million a year.

The U.S. Bird Avoidance Model (BAM) is a program designed to create models that can predict ways to reduce the probability of aircraft colliding with birds. The program, which relies heavily on technology known as the Geographic Information System (GIS), integrates the relationships among the geographic range and habitats of different species of birds, their migration patterns, and breeding habits. Among the products of the research are predictions about the chances of birds and airplanes crossing paths. With such information, flight plans can be formulated that reduce the chances of midair collisions.

The goal of research by DeVault and other scientists at Purdue University is to collect data that will make BAM more sophisticated and effective. They gather data on flight characteristics, habitat use, and home range size for species of birds that are particularly problematic in regard to collisions with aircraft.

Turkey vultures, black vultures, and red-tailed hawks have been singled out for some of the studies because of their abundance in many regions and their large size. The wingspan of a turkey vulture is six feet, making such birds a formidable threat to any airplane. Unlike other large birds such as geese or herons, vultures and hawks spend a large percentage of their time soaring on thermal updrafts. During fair weather, DeVault's radio-tagged black vultures on the Savannah River Site in South Carolina spent about 55 percent of their daytime hours in flight. Turkey vultures spent about 63 percent of their day aloft. Thus they are not only huge but are potentially in harm's way more often than many other types of birds. The collected data from such studies will be used to refine the current BAM, with the hope of making it more effective in preventing bird strikes.

The most serious clash of military aircraft with birds occurred in 1995 when an air force plane collided with a flock of three dozen geese during takeoff from Elmendorf AFB in Alaska and sucked at least three into the engines. The plane crashed about a mile from the runway and all 24 pilots and passengers were killed. Over the years, about 70 documented collisions with Canada geese have cost the military more than $85 million in lost or damaged equipment; however, 7 recorded encounters between aircraft and white pelicans have caused damage to aircraft totaling more than a quarter of a billion dollars. Of the big birds, turkey vultures are most commonly hit by aircraft; more than 450 known strikes having been recorded.

Any collision of an aircraft with a big bird or flock of smaller ones could cause an airplane's engines to malfunction and lead to a crash. Hence, research to understand the ecology of birds will help in coordinating the flight plans of planes with those of birds, which can be critical in avoiding potential air crashes that could occur anywhere and anytime, during war or peace.

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