News

Migrating birds increase risk to aircraft

  • Published
  • By Darlene Cowsert
  • Air Force Safety Center
KIRTLAND AIR FORCE BASE, N.M. (AFNS) --  As summer fades into fall, birds begin to migrate south to their wintering grounds. That migration means one thing to pilots and airfield managers: a dramatic increase in the risk of bird strikes.

Monthly trends recorded from 1995 - 2010 by the Air Force Safety Center Aviation Safety Division indicate the number of strikes typically increase from about 6,500 in July to more than 9,000 in September and October.

Bird strikes are much more common in late summer and early fall than during the rest of the year; strikes generally increase about 40 percent over this period. said Lt. Col. Russ Parker, 446th Airlift Wing flight safety officer, Joint Base Lewis-McChord, Wash.

"The Pacific flyway, a major migratory route from Alaska to Central America, traverses the West Coast directly across our local flying area, said Lt. Col. Russ Parker, 446th Airlift Wing flight safety officer. "Migrating birds generally fly about 2,000 feet above ground, but they make frequent stops for foraging in the local area."

For the period 1995 - 2010, the Air Force reported 64,946 strikes costing a total of more than $527 million, according to Dan Sullivan, the acting chief of the AFSC Bird/Wildlife Aircraft Safety Hazard (BASH) Team. In 2010, 4,723 reported bird strikes resulted in $22.5 million in damages, including $10 million to an F-15E Strike Eagle following engine ingestion of a Black Vulture.

"Flocking birds are especially dangerous," said Ted Wilkens, a BASH Program initiatives specialist, "because that can lead to multiple strikes or impacts."

While large-bodied birds generally create significantly more damage, smaller birds are responsible for the majority of strikes, officials said. For example, perching birds, Horned Larks and American Mourning Doves were responsible for 6,473 strikes between 1995 and 2010, costing the Air Force more than $5.5 million. By comparison, Canada Geese were responsible for 52 strikes, costing more than $80 million.

"The most prevalent bird in strikes in the McChord Field area is the starling, a non-native bird that lives on base year-round. It is small, but it tends to flock, making it more of a hazard than its size would otherwise reflect," said Parker.

Starlings are actually the culprit in the worst aircraft-bird accident in history; in 1960 an Eastern Airlines aircraft impacted a large flock of starlings just after liftoff in Boston. Sixty-two passengers and crew were killed after the aircraft stalled and crashed into the harbor.

"Another local problem bird is the Canada Goose," said Parker. "We have both resident and migratory populations of Canada Geese in the local area. Due to its large size and tendency to flock, it is a significant hazard for aircraft."

A flock of Canada Geese was the cause of the 1995 AWACS crash in Alaska that killed 24 airmen.

Most bird strikes occur below 3,000 feet during aircraft initial climbs or airfield approaches, Sullivan said. "Airfield strikes account for about 45 percent of all reported strikes and 50 percent of all damage costs."

As bird populations increase due to adaptation to their surroundings and conservation efforts, so have Air Force efforts expanded to educate aircrews about tracking migratory patterns and activity and to ensure base-level managers maintain robust mitigation programs.

"Better land use management of areas on and adjacent to airfields, improved bird identification processes, use of bird detection radar and easily accessible systems to track migratory activity and report strikes are all valuable tools in reducing the number of incidents," Wilkens said.

"Our local mitigation practices heavily focus on aircrew education and awareness of BASH (Bird Aircraft Strike Hazard) flying windows," said Parker. "During periods of potentially heightened bird activity, such as sunrise and sunset, we may restrict local flying to mission essential sorties only. We advise our crews to avoid areas that attract birds, such as low level flight over lakes, rivers, and wetlands."

Air Force installation safety offices are responsible for managing base-level BASH programs with cross-functional participation. The AFSC BASH Team is available to provide local managers technical assistance in control techniques, habitat management, coordination with outside agencies as well as objective bird strike data analysis.
 
For more information visit www.afsc.af.mil/organizations/bash/index.asp  (Sandra Pishner, 446th Airlift Wing Public Affairs, contributed to this report)