Bat Incidents with U.S. Civil Aircraft

Abstract

Wildlife collisions with aircraft (hereafter incidents) threaten human safety and cause substantial economic loss. Although more than 97% of wildlife incidents with U.S. civil aircraft involve birds, damage is more than 4.5 times more likely to occur during a mammal incident (e.g., deer, canids). Bats are the only mammals with the potential to be struck by aircraft outside the airport environment (at least 152.4 m above ground). We examined the Federal Aviation Administration's (FAA) National Wildlife Strike Database from 1990 to 2010 to estimate the frequency of bat incidents with aircraft within the U.S. and the risk relative to other wildlife incidents. We summarized 417 bat incidents with U.S. civil aircraft. There were 10 bat species or species groups involved in these incidents; however, 68.9% were not identified to species. Most (85.7%) bat incidents occurred at Part 139 certificated airports that receive regularly-scheduled passenger flights with more than nine seats or unscheduled flights with more than 30 seats. More incidents occurred during August (28.3%) than any other month. Most bat incidents occurred at night (81.7%), but the greatest incident rate occurred at dusk (57.3%). More incidents occurred during aircraft landing (85.0%) than take-off (11.2%) or other phases of flight (3.7%). 'Minor' damage to aircraft occurred on only two occasions but no damage costs were reported. Incidents coincided with bat behavior, including diel activity, migration, hibernation, and juvenile recruitment. We conclude bat incidents are low risk to U.S. civil aircraft and have minimal economic effect on the U.S. civil aviation industry.