When Birds Strike

 - November 1, 2006, 3:41 AM

You might want to think twice about taking off at 10 a.m. in the months of May, August, September or October, because the U.S. Air Force’s copious statistics (http://afsafety.af.mil/AFSC/Bash/ home.html) on the birdstrikes it has suffered from 1973 through January this year show those to be the peak risk periods.

The takeoff roll is the most vulnerable phase of flight (accounting for 14 percent of all birdstrikes recorded by the USAF) other than the military specialty of low-level cruise, which accounts for 56 percent. Some 40 percent of birdstrikes happen at below 200 feet, and wings/rotors and radomes take the brunt, absorbing almost 40 percent of the hits. “Inside engine, unspecified” accounts for 2 percent, “Inside engine No. 1” nearly 6 percent and “Inside engine No. 2” more than 4 percent.

The horned lark is the bird struck most often, with 1,500 incidents, but it’s a small bird and the average cost per strike is only about $1,700. Damage from turkey vulture strikes (nearly 500 recorded), however, costs about $200,000 per episode, putting the $200,000 annual cost of McGuire’s falconry program in perspective. Hawks and kestrels figure prominently in the birdstrike numbers. The infamous Canada goose has tallied 72 hits causing more than $85 million in damage (although this figure is puzzling, since Canada geese were blamed for downing the AWACS at Elmendorf in 1995, and press reports at the time put the value of that airplane at $180 million).