Wildlife Strikes with U.S. Military Rotary-Wing Aircraft Deployed in Foreign Countries

Human–Wildlife Interactions 8(2):251–260, Fall 2014 Wildlife strikes with U.S. military rotary- wing aircraft deployed in foreign countries BRIAN E. WASHBURN, U.S. Department of Agriculture, Wildlife Services’ National Wildlife Research Center, 6100 Columbus Avenue, Sandusky, OH 44870, USA [email protected] PAUL J. CISAR, Logistics Division, U.S. Army Aberdeen Test Center, Aberdeen Proving Grounds, MD 21005, USA TRAVIS L. DEVAULT, U.S. Department of Agriculture, Wildlife Services’ National Wildlife Research Center, 6100 Columbus Avenue, Sandusky, OH 44870, USA Abstract: During recent decades, rotary-wing aircraft (helicopters) within the U.S. Department of Defense (e.g., U.S Army and U.S. Air Force) have been deployed overseas to conduct a variety of noncombat and combat missions. Our objective was to conduct a comprehensive analysis of wildlife (birds, bats, insects) strikes with U.S. Army and U.S. Air Force rotary- wing aircraft during overseas deployments. We acquired all available wildlife strike information involving U.S. Army and U.S. Air Force military rotary-wing aircraft engaged in flight operations associated with U.S. military bases around the world during 1990 to 2011. Wildlife strikes with military rotary-wing aircraft occurred in >31 foreign countries. Almost two-thirds of wildlife strikes to U.S. Army aircraft occurred during deployments in the Middle East (e.g., Iraq), whereas, strikes to U.S. Air Force aircraft occurred most frequently in Afghanistan and the Middle East. Month, time of day, and location (i.e., on airfield or off airfield) influenced the frequency of wildlife strikes. Wildlife strikes occurred most frequently when aircraft were traveling en route or were engaged in terrain flight. Larks, doves, pigeons, and various perching birds were the species most frequently struck by military aircraft. Wildlife strike records related to U.S. military overseas operations represent a unique source of ornithological information from areas of military conflict. Key words: Afghanistan, helicopters, human–wildlife conflicts, Iraq, military, rotary-wing aircraft, wildlife strikes During the last 2 decades, a great deal civil and military aviation worldwide (Thorpe of armed conflict, and political upheaval has 2010, Dolbeer et al. 2012, DeVault et al. 2013). occurred in the Middle East (e.g., Iraq) and south- Although rotary-wing aircraft conduct es- central Asia (e.g., Afghanistan), much of which sential missions during overseas deployments, has involved the deployment of U.S. military no assessment of wildlife strikes to military aircraft. Rotary-wing aircraft (i.e., helicopters) rotary-wing aircraft during these operations have carried out numerous noncombat and has been conducted. The objectives of this combat missions during Operation Desert project were to conduct a comprehensive Storm in Kuwait and Iraq during 1990 to 1991, analysis of data available from U.S. Army and Operation Enduring Freedom (2001 to 2014) in U.S. Air Force on wildlife strikes with rotary- Afghanistan, and Operation Iraqi Freedom in wing aircraft during flight operations outside Iraq during 2003 to 2010. Air crews of military of the USA. rotary-wing aircraft face many hazards to flight safety, including physical hazards (e.g., Methods wires, buildings), weather, human factors (e.g., We acquired all available wildlife strike fatigue), and hostile actions (e.g., antiaircraft records for U.S. Army rotary-wing aircraft weaponry) that result in damage to aircraft during 1990 to 2011 from the U.S. U.S. Army and human injuries and fatalities (Couch and Combat Readiness-Safety Center and for U.S. Lindell 2010, U.S. Army 2012). Collisions with Air Force rotary-wing aircraft during 1994 to wildlife represent an important, but unstudied, 2011 from the U.S. Air Force Safety Center. We physical hazard to military rotary-wing aircraft created a new database and conducted a line- used in conducting overseas flight operations. by-line review of each wildlife strike record to Wildlife collisions with aircraft (wildlife strikes) ensure data integrity and consistency. Due to pose increasing risks and economic losses to the diverse nature of the data fields contained 252 Human–Wildlife Interactions 8(2) within the 2 military databases, we also out phase were in the later stages of taking off extracted data from narrative records, accident (≥30 m AGL and moving forward). reports, and incident information (e.g., pilot We defined a wildlife strike event with a commentary). When necessary, we recoded or rotary-wing aircraft as a damaging strike by classified wildlife strike information to allow bird, bat, or insect if there was any amount of for consistency in terminology categories damage to the aircraft reported. Damaging between the 2 military service strike records for wildlife strikes varied greatly in the amount of variables (e.g., the phase of flight the aircraft actual damage incurred, ranging from minor was in when the bird strike occurred). abrasions found on the airframe or an aircraft We parsed our database to include only component to the complete destruction of an wildlife strikes to U.S. Army and U.S. Air aircraft engine. Force military rotary-wing aircraft engaged in Previous evaluations of wildlife strikes flight operations during overseas deployments with civilian fixed-wing aircraft (Dolbeer et (i.e., outside of the USA) associated with U.S. al. 2006) and rotary-wing aircraft (Washburn military bases around the world. Notably, et al. 2013, Washburn et al. 2014) have shown these flight operations were conducted during that important patterns might exist among training exercises, peace keeping operations, wildlife strikes that occur within airport and recognized in-theater combat operations. environments compared to those that occur We determined the time of day each wildlife away from airports and military airfields. For strike event occurred based on the local time each wildlife strike, the reported location of reported in strike records. Wildlife strikes the strike event (if known) was determined occurring between 0800 and 1800 hours local to be on-airfield if the aircraft was within the time were categorized as day, while strikes horizontal delineation of an airfield when between 2000 to 0600 hours were categorized the strike occurred. Off-airfield strikes were as night events. Dawn strike events occurred defined as wildlife strike events that were during 0600 to 0800 hours, and dusk events reported to have occurred when the aircraft was occurred during 1800 to 2000 hours. not on or flying over an airfield (e.g., an aircraft Phase of flight was defined as the phase traveling en route to a specified destination). of flight the aircraft was in at the time the wildlife strike occurred (Federal Aviation Animal analysis Administration 2000, U.S. Army 2012). Aircraft Per required U.S. Air Force protocol, reports in the en route phase of flight were flying at an of strikes and remains of animals from all altitude of 305 m above ground level (AGL) or wildlife strikes with U.S. Air Force aircraft were higher. Rotary-wing aircraft that were flying sent to the Smithsonian Institution’s Museum (moving forward) at an altitude of <305 m of Natural History, Feather Identification AGL were classified as being in-terrain flight. Laboratory. Wildlife strike identifications are Hovering rotary-wing aircraft were off the made by the Smithsonian Institution staff ground (but <305 m AGL) and stationary (i.e., using feathers (Laybourne and Dove 1994), no horizontal movement). Aircraft on-approach hair (in the case of bats; Peurach et al. 2009), were in early stages of the landing process (≥30 or DNA analysis (Dove et al. 2008). For each m AGL and moving forward), typically on or individual strike event, the wildlife involved over an airfield. Landing rotary-wing aircraft was assigned to 1 of 20 groups (DeGraff et al. were in the final stages of landing and were <30 1985, Kissling et al. 2011, Wielstra et al. 2011). m AGL. Rotary-wing aircraft that were taxiing In cases where the wildlife involved was were moving along the ground or just above the identified to the species level, we assigned ground (<3 m AGL) in a transition from 1 part that wildlife strike to the appropriate group of the airfield to another (e.g., traversing from based on the species involved. Wildlife strike the hanger to an active helipad). Aircraft in the events involving >1 individual animal (e.g., take-off phase were in the process of leaving a flock of birds) were enumerated the same the ground and were ascending upward (but as wildlife strike events that involved only 1 <30 m AGL). Rotary-wing aircraft in the climb- animal, because the number of individuals Wildlife strikes • Washburn et al. 253 Table 1. Number of reported wildlife strikes, by varied among variables and analyses. We foreign country, involving rotary-wing aircraft for used linear regression analyses, ANOVA, and the U.S. Army (1990 to 2011) and U.S. Air Force t-tests to determine if significant differences (1990 to 2011). occurred in the number of reported wildlife Geographic area and country U.S. Army U.S. Air Force strikes among years and times of recognized Southwest Asia theaters of combat operations (Zar 1996). We Afghanistan 12 177 used chi-square analysis (Zar 1996) to compare Turkey 3 5 the number of wildlife strikes with U.S. Army Persian Gulf and U.S. Air Force rotary-wing aircraft among Iraq 136 117 months and time of day. Descriptive statistics Kuwait 3 3 were used to quantify the frequency of wildlife Saudi Arabia 6 1 strikes that occurred among the aircraft phases Asia and Pacific of flight. Data are presented as mean ±1 Rim standard error (SE). South Korea 28 35 We also summarized wildlife strikes that Thailand 1 6 Japan 15 occurred on-airfield separately from those that Philippines 2 occurred during flight operations off-airfield.

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