Accident Analysis: Look! Up in the sky!

Most bird strikes are less spectacular, but then, most birds don’t have the heft of a 15-pound turkey. Of course, since impact forces increase with the square of velocity, a great deal of mass isn’t always necessary. The Wildlife Strike Database that Embry-Riddle Aeronautical University maintains for the FAA includes examples of aircraft damage caused by collisions with sparrows, wrens, and black-capped chickadees (average weight: less than half an ounce). Human fatalities are rare—the database lists just 26 since 1990—but the sudden convergence of gull or goose with windshield, empennage, or rotor blade makes whatever’s left of the flight uncomfortably exciting. (It’s even worse for the bird.)

Not surprisingly, the birds that most frequently cause damage are larger varieties that get into lots of collisions—chiefly ducks, geese, and hawks. Pigeons and doves, with more than 12,000 reports, edged out gulls and terns (just under 11,000) as the ones most commonly identified in all strikes, but the latter damaged more than three times as many aircraft.

According to a 2013 report by the U.S. Department of Agriculture, more than half of all strikes occur between July and October. Three-quarters happen below 500 feet agl, and every additional thousand feet reduces the remaining risk by another 40 percent. Nearly two-thirds take place during daylight hours; and curiously, strikes are almost twice as common during descent, approach, and landing as takeoff and climb. Together, these phases account for 97 percent of the total incidents.

Still, there are no guarantees. The record altitude was 31,300 feet—and in October 2007, a Piper Seminole on a dual night cross-country departed controlled flight, crashed into a bog, and was destroyed. Investigators found that it had been rendered uncontrollable after a collision with a Canada goose bent the left side of its stabilator 90 degrees—in level cruise flight some 3,200 feet above the ground.

AOPA Air Safety Institute statistician David Jack Kenny is grateful that his wife’s bird feeders are a good five miles from the airport.