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Bird Hazards

Introduction:

  • Birds and other wildlife pose serious hazards to pilots during day and night, especially in the terminal area
  • Migratory activity is generally predictable along recurring flyways but their appearance on your route of flight will always be unexpected
  • Proper background and preflight planning can help mitigate the risks of a bird strike
  • Although steps can be taken, sometimes bird strikes will happen which warrant a report
  • Preflight planning information found at http://www.usahas.com/
Major Migratory Flyways, U.S. Fish and WIldlife Service
Figure 1: Major Migratory Flyways, U.S. Fish and WIldlife Service

Migratory Bird Activity:

  • Bird activity increases because of migrations during the months of March through April, and August through November
  • The altitudes of migrating birds vary with winds aloft, weather fronts, terrain elevations, cloud conditions, and other environmental variables
  • While over 90% of the reported bird strikes occur at or below 3,000 feet AGL, strikes at higher altitudes are common during migration
  • Ducks and geese are frequently observed up to 7,000' AGL and pilots are cautioned to minimized en route flying at lower altitudes during migration
  • Migratory bird activity is considered the greatest potential hazard to aircraft because of their size, abundance, or habit of flying in dense flocks
  • Considered the greatest potential hazard to aircraft because of their size, abundance, or habit of flying in dense flocks are gulls, waterfowl, vultures, hawks, owls, egrets, blackbirds, and starlings

Migratory Flyways:

  • Major Migratory Flyways:

    • The Atlantic Flyway: parallels the coast
    • The Mississippi Flyway: stretches from Canada, through the Great Lakes and follows the Mississippi River
    • The Central Flyway: represents a broad area east of the rockies through central America
    • The Pacific Flyway: follows the west coast
  • Other Migratory Flyways:

    • There are also numerous smaller flyways which cross these major north-south migratory routes

Reducing Bird Strike Risks:

  • When encountering birds en route, climb to avoid collision, because birds in flocks generally distributed themselves downward, with lead birds being at the highest altitude
  • Avoid overflight of known areas of bird concentration but if you must, do not fly low altitudes
  • Charted wildlife refuges and other natural areas contain unusually high local concentration of birds which may create a hazard to aircraft
  • Strike Information Summaries provide historical data using various parameters
  • Preflight planning information found at http://www.usahas.com/

Reporting:

  • Bird Strikes:

    • The most serious strikes are those involving ingestion into an engine or windshield strikes
    • Engine ingestion may result in sudden loss of power or engine failure
    • Windshield strikes have resulted in confusion, disorientation, loss of communications, and aircraft control problems
    • Timely reporting allows Air Traffic Control as well as other pilots in the area to remain proactive
    • If you do have a bird or other wildlife strike then report it using FAA Form 5200-7, Bird/Other Wildlife Strike Report available in the AIM Appendix 1, FSS, FAA offices or online at http://wildlife-mitigation.tc.faa.gov
      • Reports are used to develop standards to cope with potential hazards and for documentation of necessary habitat control at airports
      • Additionally, completed reports are available to pilots for learning from other's experience
  • Wildlife Activity:

    • If you observe birds or other animals on or near the runway request airport management to disperse the wildlife before taking off
    • Also contact the nearest FAA ARTCC, FSS, or tower (including non−Federal towers) regarding large flocks of birds and report the:
      • Geographic location
      • Bird type
      • Approximate numbers
      • Altitude
      • Direction of bird flight path
    • Many airports advise pilots of other wildlife hazards caused by large animals on the runway through the A/FD and the NOTAM system

USAF Condition Codes:

  • SEVERE:
    • Bird activity on or immediately above the active runway or other specific location representing high potential for strikes
    • Supervisors and aircrews must thoroughly evaluate mission need before conducting operations in areas under condition SEVERE
  • MODERATE:
    • Bird activity in locations representing increased potential for strikes
    • BWC moderate requires increased vigilance by all agencies and supervisors and caution by aircrews
  • LOW:
    • Bird activity on and around the airfield representing low potential for strikes

Flights Over Charted U.S. Wildlife Refuges, Parks, and Forest Service Areas:

  • The landing of aircraft is prohibited on lands or waters administered by the National Park Service, U.S. Fish and Wildlife Service, or U.S. Forest Service without authorization from the respective agency except for:
    • When forced to land due to an emergency beyond the control of the operator
    • At officially designated landing sites
    • An approved official business of the Federal Government
  • Pilots are requested to maintain a minimum altitude of 2,000' above the surface of the following:
    • National Parks
    • Monuments
    • Seashores
    • Lakeshores
    • Recreation Areas and Scenic Riverways administered by the National Park Service
    • National Wildlife Refuges
    • Big Game Refuges
    • Game Ranges and Wildlife Ranges administered by the U.S. Fish and Wildlife Service
    • Wilderness and Primitive areas administered by the U.S. Forest Service
  • FAA Advisory Circular AC 91-36, Visual Flight Rules (VFR) Flight Near Noise Sensitive Areas, defines the surface of a national park area (including parks, forests, primitive areas, wilderness areas, recreational areas, national seashores, national monuments, national lakeshores, and national wildlife refuge and range areas) as: the highest terrain within 2,000' laterally of the route of flight, or the upper most rim of a canyon or valley
  • Federal statutes prohibit certain types of flight activity and/or provide altitude restrictions over designated U.S. Wildlife Refuges, Parks, and Forest Service Areas
    • These designated areas, for example: Boundary Waters Canoe Wilderness Areas, Minnesota; Haleakala National Park, Hawaii; Yosemite National Park, California; and Grand Canyon National Park, Arizona, are charted on Sectional Charts
  • Federal regulations also prohibit airdrops by parachute or other means of persons, cargo, or objects from aircraft on lands administered by the three agencies without authorization from the respective agency except when:
    • Emergencies involving the safety of human life
    • Threat of serious property loss

Airbus A320 Crashes Into Hudson River After Bird Strike
Figure 2: Airbus A320 Crashes Into Hudson River After Bird Strike

Case Studies:

  • NTSB Identification: DCA09MA026: The ingestion of large birds into each engine, which resulted in an almost total loss of thrust in both engines and the subsequent ditching on the Hudson River. Contributing to the fuselage damage and resulting unavailability of the aft slide/rafts were (1) the Federal Aviation Administration’s approval of ditching certification without determining whether pilots could attain the ditching parameters without engine thrust, (2) the lack of industry flight crew training and guidance on ditching techniques, and (3) the captain’s resulting difficulty maintaining his intended airspeed on final approach due to the task saturation resulting from the emergency situation

Conclusion:

  • During the past century, wildlife-aircraft strikes have resulted in the loss of hundreds of lives worldwide, as well as billions of dollars in aircraft damage
  • The FAA maintains a comprehensive program to address wildlife hazards
  • Through policy and guidance, research and outreach, we strive to stay ahead of the issue
  • Any emergency situation requires prompt action by the pilot
  • Be especially familiar with engine out procedures when in the vicinity of known bird hazards
  • Collisions of landing and departing aircraft and animals on the runway are increasing and are not limited to rural airports
    • These accidents have also occurred at several major airports. Pilots should exercise extreme caution when warned of the presence of wildlife on and in the vicinity of airports
  • Interestingly enough, birds fly at night at about the same frequency as during the day
    • Furthermore, birds tend to be VFR creatures and avoid clouds
  • Remember that in addition to birds, there are other animals that could be considered a strike hazard

References: