Bird Strike Committee Proceedings


Date of this Version

August 2001


Wright et al. (1988) stated that although deer strikes comprise only about 2% of total reported wildlife strikes, 86% of those strikes damaged the aircraft. Dolbeer et al. (2000) ranked deer as the most hazardous species to aircraft based on damage and effect-on-flight. On January 14, 2001, a Learjet collided with two white-tailed deer (Odocoileus virginianus) on an airport in Troy, Alabama. Both pilots were critically injured and would have perished in the fire that destroyed the aircraft if rescuers had not arrived quickly. The above example of a damaging wildlife strike to an aircraft is not uncommon. Wildlife strikes to civil aircraft are a serious economic and safety problem in the United States (Cleary et al. 2000). However, reporting of bird or other wildlife strikes to aircraft (Federal Aviation Administration [FAA] Form 5200-7) remains voluntary. Further, prior to this, the strike data for non-avian species are incomplete prior to 1991. The forms for reporting strikes before 1991 only collected bird strike data. The author gathered deer and mammal strike data prior to 1991, from the National Transportation Safety Board and the Aviation Safety Reporting System databases. The white-tailed deer populations in the United States have increase dramatically in recent years. In 1900, white-tailed deer had been hunted to near extinction with only about 100,000 remaining, but they now number over 26 million (Jacobson and Kroll 1994). From 1982 to 2000, 901 mammal strikes with civil aircraft were reported to the FAA (Table 1). The number of damaging strikes was 502 (71%) (Table 1). Deer strikes totaled 518 (there were also 3 moose, 7 elk and 6 pronghorn strikes). The number of damaging strikes caused by deer was 425 (86%) (Table 1). During this same period, 47 states reported deer strikes (Table 2), with 404 (78%) of the reports coming from states east of the Mississippi River. More strikes occur in November (20%) than in any other month (Figure 1). The strike rate (number/hr) was 3, 7, and 11 times greater at dusk than during night, dawn, or day respectively (Table 3). About 57% of deer strikes occurred during the landing phase of flight (Figure 2), making landing at dusk in November the most likely time for deer strikes. In addition, 75% of strikes had a negative effect on the flight (Figure 3). Only 20% of reports indicating damage provided estimates of repair costs. The mean cost for these reports was $74,209 (range $100- $1,400,000). Reported human injuries resulting from deer strikes have been few (20 from 1982-March 2001) but the potential exists for a major disaster. For example, aircraft with a capacity of 101-380 passengers were involved in 12% of the reported strikes (Table 4).