United States Air Force Europe Bird Strike Hazard Reduction

Transcription

1 203 United States Air Force Europe Bird Strike Hazard Reduction Maj. Gerald Harris United States Air Force Europe Introduction The United States Air Force Europe (USAFE) has a variety of bases, which extend throughout Europe, Africa, and the Middle East. With flight operations spanning such a variety of environments and climates, birdstrike reduction efforts are quite a challenge. The Air Force publishes general guidelines, which describe how to set up a basic Bird Air- Strike Hazard (BASH) program. These guidelines are not all-inclusive but provide a foundation on which to build an effective program. Each base then builds upon this basic document to develop an effective bird strike reduction program based upon each bases particular bird problems. Birds aren t the only problem, there are other animals that can be hazardous to aircraft, including deer, foxes, dogs, pigs, etc. Instead of a birdstrike reduction program, a more appropriate name might be wildlife management program. One of the key factors in determining how to conduct an effective program is environmental control. Determine what makes the airfield environment attractive to birds, and other animals, and reduce the attractiveness as much as possible. Bird Strike Statistics Why is the Air Force so interested in having a BASH program? We have lost 33 aircrew and 14 aircraft in the past 12 years due to birdstrikes. The average cost to the Air Force is 36 million dollars per year. And it s not only fighters which have had fatalities due to birdstrikes. The accident that really caught our attention was the E-3 AWAC s crash on takeoff in Elmindorf Alaska. It showed that not only small fighter aircraft were vulnerable to birdstrikes, but also large multiengine aircraft were susceptible catastrophic birdstrikes. What can we do to help reduce these numbers? If you look at the statistics, the Air Force has recorded over 33,000 bird strikes since That averages out to approximately 2600 bird strikes a year. Twenty-nine percent of all birdstrikes are unknown to the crew and are not discovered until after flight. If you take out the unknown bird strikes it turns out that 65% of all birdstrike occur in the air field environment (Figures 1 & 2). The second largest phase of military flight involving bird strikes is low-level with 23% of the known strikes. These are military aircraft flight statistics which include low-level training at the altitudes most bird strikes occur. Commercial aircraft typically do not fly low level, below 1000 ft AGL, which means that an even higher percentage of their bird strikes occur around the airfield. The good news is that this is the environment that we have the most control over. We can manipulate the airfield environment to make it less attractive in order to reduce bird populations in these areas.

2 204 It is important to know that bird strikes occur at different rates depending on the time of year. The majority of bird strikes occur during the two primary migration periods: during the fall migration, (September and October), when birds fly north to south, and during the spring migration when migrating birds return north during the months of April and May. It is also important to realize that the least number of birdstrikes occur during the winter months of December, January and February. Knowing the migration seasons and tracking the migration routes can allow flight crews to flight plan around known migratory routes and reduce their risk of birdstrikes. The migration routes are particularly important to know because the majority of migratory birds are the larger bird species which if hit can cause significant damage to aircraft. These include geese, ducks and storks. Another interesting statistic concerns the altitudes at which bird strikes occur. Figure 3 shows that the vast majority of bird strikes, 66%, occurred below 500 feet Above Ground Level (AGL) and 80% of all bird strikes occur below 1000 feet AGL. The less time spent below 1000 ft the less your chances are of having a birdstrike. BASH Programs In order to make the environment less attractive to birds and other animals you need to ask, what are birds looking for? A good analogy is the following: Birds are like teenagers - they are looking for three things. A place to eat, a place to sleep, and a place to breed. Understanding what is considered attractive or unattractive to birds will help you make environmental decisions to reduce their attractiveness of airfields to birds. What can be done? Maintain grass height at 20 to 40 centimeters. Birds like to have a clear view around them so they can see predators approaching. If the grass height is kept high they will not land. Bare areas allow birds to clearly see predators, therefore they will land in these areas. Plant grass in these areas to reduce the bare spots. Trees attract birds for resting and nesting. Keep the airfield area clear of trees to reduce the areas for birds to nest and roost. Open landfills and garbage dumps attract birds. Do not place a landfill near an airfield or move landfills currently located near airfields. Standing water attracts birds. Eliminate standing water in the airfield environment if possible. Insure that drainage ditches do not hold standing water. Work with your environmental control folks to reduce food sources for birds around the airfield. This can include the use of insecticides and landscaping of the areas around the airfield. Educating flyers on local bird populations, migration routes and current high-density bird locations adds additional information. Aircrews can then use risk management to determine when and where to fly. BIRDTAMs are notices to airmen informing them of known concentrations of birds during different times of the year. During the migratory seasons low-level routes should be varied to avoid known bird concentrations. Flight along rivers and waterways are reduced. Flight routes can be planned to cross perpendicular to peaks and ridgelines minimizing the hazard of hitting soaring raptors, which use the thermals over the peaks. Low level routes and altitudes are planned to avoid seasonal

3 205 Pattern Landing Missed Final/ Approach Descent Cruise Range Unknown Low-Level Figure 1: Bird strikes by phase of flight Climb Take-Off Figure 2: Bird strikes by phase of flight, without unknown category Low-Level 23% Climb 4% Airfield Environment 66% Descent 1% Cruise 1% Range

4 to % 1501 to % 1001 to % 2001 to to 3000 Above 3000 Below % Figure 3: Bird strikes by altitude Figure 4: Crane Migration over Northern Germany , German Military Geophysical Office - Biology Section

5 207 migration routes. Other options include setting minimum flight altitudes for specific legs of low-level routes and known roosting areas. When low-level routes become more hazardous due to bird migration, consider closing low-level routes on days that aircrews have reported high bird activity. Real-time warnings can come from a variety of sources but often come from aircrew that encounter large concentrations of birds in flight and report them back to their home station. Information is passed on to other aircraft in that area and in some cases lowlevel routes are closed based on bird sightings from aircrew. The German Air Force uses an enhanced air defense radar system in conjunction with the German Military Geophysical Office to produce NOTOM s based on real time bird radar returns (Figure 4). The locations of birds are passed on to aircrews using a grid map system. Once high concentrations of birds are located, the aircrews are notified of the map grid section which is effected and flight through those areas is prohibited. USAF uses local bird watch conditions to alert aircrew to bird activity around the airfield and restrict their flying during times of high bird activity. Bird Watch Condition codes are used to rapidly communicate changes in bird activity around the airfield. Bird Watch Condition SEVERE: High bird population on, or immediately above, the active runway or other specific locations that represents a high potential for strike. Supervisors and aircrews must thoroughly evaluate mission needs before conducting operations in areas under Condition SEVERE. Immediate action is required to lower the threat. Bird Watch Condition MODERATE: Increased bird population in locations which represent an increased potential for strikes. This condition requires increased vigilance by all agencies and supervisors and caution by aircrews. Bird Watch Condition LOW: Normal bird activity on and above the airfield with a low probability of hazard. This condition will be in effect for the remainder of the flying day, whenever a severe or moderate condition has been declared and subsequently downgraded. Upon extended normal bird activity, no bird watch condition need be declared. Bird forecasts predict where migratory routes are and when birds will be using them. Once birds have been sited around the airfield frightening techniques need to be employed to remove them from the airfield. Some types of frightening techniques include playing distress calls over a loud speaker system to scare birds from the airfield. Distress tapes are available for a variety of bird species. Other techniques include bird-scatter guns, which fire a charge into the air. The round then explodes making a big bang, which startles the birds and causes them to move. The charge is fired so that it will explode over the top of the birds driving them away from the runway. Gas cannons are another dispersal method used that produces a loud noise and can be programmed to fire at specific times. To use gas cannons properly they need to be moved to different locations so the birds don t get acclimated to same sounds coming from the same area. In some cases lethal methods may be required to reduce local bird populations. We employ gun clubs to come out to the airfield on prearranged airfield hunts. The hunters kill

6 208 the birds that could not be dispersed by other means. This is also effective for controlling other wildlife that is a hazard on the airfield, deer and rabbits for example. Before hunts can begin, we make sure we get the proper permits and that all hunters have been properly trained. Falconry programs have been introduced at many bases in Europe and are very successful, when used in conjunction with other methods, at keeping birds away from the airfield. Conclusions Why have BASH programs? Because birdstrikes kill people and damage aircraft, which effects your ability to maintain our forces. We know that birds want a place to eat, sleep, and breed, so we can deny them that by changing the airfield environment to make it as unattractive as possible. If we combine active controls like falconry, bird scatter cartridges and gas cannons we can further reduce the number of birds near the airfield. By letting our aircrew know when birds are in the area, and by planning flights to limit exposure we can further reduce the risk of birdstrikes. Advances in radar systems are allowing us to see real-time bird movement and forward warnings to our aircrews. Birdstrikes are a hazard that will always be there. We will never eliminate them entirely, but we can substantially reduce the risk of having a birdstrike by controlling the airfield environment, educating our aircrew, and continuing to develop technology that gives us real time bird location data.