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Nature's Protected Areas: A Potential Risk To Aircraft

by Al Peyus
Reprinted with permission from FAA Aviation News

Grab a sectional chart. Take a look around it. Do you see any areas outlined with a solid blue line with blue dots on the inside of the line? Do you know what these areas are? When was the last time you took a close look at these areas? Do you know why they are to be avoided or their altitude restrictions observed? Is it really that important to observe the minimum published altitudes?

What goes on inside these blue lined and dotted areas that require aircraft to remain well above the ground or above the highest obstacle within their boundaries and that can pose a serious hazard to aircraft flying in or around these areas?

The definitions for the markings normally can be found somewhere along the edge of the sectional. Briefly, the blue line marks the boundary of National Park Service areas, U.S. Fish and Wildlife Service areas, and U.S. Forest Service wilderness and primitive areas. The definition includes aircraft usage restrictions, minimum altitudes, and other restrictions noted in Advisory Circular (AC) 91-36D dated September 17, 2004, Visual Flight Rules (VFR) Flight Near Noise-Sensitive Areas. These areas can include bird sanctuaries, national wildlife refuges, wilderness areas, or national parks. When charted, the name, which normally includes the type of area, is located near or within the marked boundary area.

Why must aircraft stay at or above the posted altitudes if it is just wildlife moving around on the ground? After all, according to Title 14 Code of Federal Regulations (14 CFR) section 91.119, Minimum safe altitudes: General, aircraft can fly in rural areas as long as the aircraft remains at least 500 feet from any person, vessel, vehicle, or structure and be legal. So why not in these lined and dotted areas?

A little history will help you understand what started all these protected areas. The first national park was set aside by the U.S. Government to protect the uniqueness of the park area. The land was set aside to remain as it is to allow the citizens of the United States, and the world, to see portions of this great country as it has always been before man started to rearrange, change, modify, and destroy the natural beauty of the land.

A perfect example is Yellowstone National Park. In 1872, President Ulysses S. Grant signed into law the creation of the first national park, declaring that Yellowstone would forever be dedicated and set apart as a public park or pleasuring ground for the enjoyment of the public. These parks are some of the most beautiful portions of our wonderfully diverse country. Today, the government provides protection, guidance for the use, and the limitations of occupancy and operation in and around these national parks and areas.

Years ago, flying tours were allowed to drop down below the walls of the Grand Canyon. After several mid-air accidents, some aircraft failing to successfully climb back out of the Grand Canyon, and a multitude of noise complaints from the public, flights below the walls of the Grand Canyon were ordered to a halt. Today, Subpart U, 14 CFR part 93, regulates flight operations in the vicinity of the Grand Canyon National Park.

The national wildlife sanctuaries, such as the Quillayute Needles National Park Refuge on the coast of Washington State, protect a wide variety of wildlife. The altitude restrictions are for the protection of the animals. Aircraft noise can scare the wildlife and disrupt the daily lives of these creatures. During mating season, aircraft can disrupt mating and, thus, potentially impact an entire generation of wildlife.


Speaking of wildlife sanctuaries and refuges, these also have altitude restrictions for aircraft and for excellent reasons! Wildlife sanctuaries and refuges can be a hazard to both the wildlife as well as aircraft. If there ever was a doubt about the safety concern, allow me to introduce you to some very attention producing numbers.

Wildlife strikes can pose a serious safety risk to aviation. Of all the wildlife strikes, birds are the number one cause (97.5%) for strikes involving aircraft. The Federal Aviation Administration (FAA) and the United States Air Force (USAF) databases contain information on 66,392 U. S. civilian and military aircraft wildlife strikes reported between 1990 and 2005. This is only a 16-year time span with more than 66,000 strikes! Of those wildlife strikes, 4,532 aircraft suffered minor damage, 2,433 aircraft received substantial damage, while 36 aircraft were destroyed! The injury count was 172 people injured to various degrees, while nine people lost their lives.

For in-flight strikes to engines, the numbers are even more impressive. There were reported 8,750 incidents with bird strikes involving aircraft in which a total of 9,206 engines were reported struck. Damage occurred to at least a third, or over 3,000 of the engines hit in bird strikes!

Let me turn your attention to another important part of this story. According to an estimate by the FAA during the same time period, yearly, yes, yearly financial losses for damage to aircraft caused by wildlife are about $500,000,000! Yep! That is $500 million dollars! Do I have your attention yet?

Aircraft repair down time after a wildlife strike is another sobering statistic. Thousands of hours are required each year to repair engines and airframes damaged by strikes. Most of the reported incidents/accidents occurred close to or around airports. Many airports are in or near national parks, wildlife sanctuaries, or refuge areas. The altitude most often listed at the time of impact is at or below 2,000 feet above ground level (AGL). More frightening is that 60% of bird strikes occur at altitudes of less then 100 feet AGL! It is a "perfect" time for a collision when aircraft are at their most vulnerable during takeoff and landing.

As stated earlier, birds of all sizes are the most common wildlife involved in reported aircraft incidents/accidents. Where do the birds come from and why are they and aircraft coming into contact so often?

Both aircraft and birds use the National Airspace System (NAS) as a road system through which to get from A to B. One of the more common places birds like to gather is the same area as aircraft/airports! The open space, plenty of nesting locations (including the engine nacelle), and plenty of food (insects, mice, other birds, and wildlife) are perfect for our feathered fowl friends. Each time an aircraft takes off or lands at a bird-occupied field, the chance of collision increases exponentially. Many birds take flight at the most inopportune time, especially when startled. Just as an aircraft lifts off or is on short final for landing, the birds on the ground take flight and scatter in every direction. When encountering birds during flight and not close to the ground, it is generally best for a pilot to climb to minimize collision. The birds will normally dive to avoid an aircraft.

Another factor is that birds do not normally have the skill, training, experience, or equipment to fly in instrument conditions. They generally fly below the cloud deck or above it. As those pilots who have flown IFR during the fog season near a game refuge or bird sanctuary can attest, the most heart racing time comes as the aircraft breaks out on top of the fog and there they are! It can get the heart pounding as the waterfowl fly over, around, and through the aircraft struts, wings, and landing gear! Now that is the type of excitement pilots would prefer not finding!

The same happens when the aircraft starts an IFR descent on the approach and passes through the bottom of the cloud deck. Suddenly there they are again! The birds seem to flow like water through and around the aircraft. All too often one of the birds will strike a portion of the aircraft. In most cases it produces minor damage to the aircraft wing, strut, or fuselage.

Being in the clouds does not necessarily guarantee safe passage around birds. There are exceptions out there, as with almost every thing! Several bird strikes have been reported in the clouds!

When a large bird like a goose, duck, or raptor strikes the windscreen or engine, it now becomes an emergency! When the aircraft windscreen is broken, the cockpit gets very noisy, cold, and highly distracting for the pilot and passengers. If the bird breaks through and enters the cockpit, there is another leap in problems. A goose weighing about 10 pounds breaking through the windscreen of a 125 mph aircraft is a mighty projectile. Slowing only slightly, it can strike the pilot or passenger with lethal impact. And we think a baseball traveling at 90 mph hitting a batter hurts!

Other potential collision locations are during flights over national wildlife sanctuaries that are the homes for migrating waterfowl. These areas attract numbers of waterfowl that astound the mind, literally; millions of birds stop over in these areas. And these are not just those birds that migrate. The local birds enjoy these areas too and arrive in very large flocks. The food is great, the water is comfortable, and the space is wide open! These locations are great for the birds, but dangerous for aircraft of all sizes.

Normal altitude restrictions over these areas start at 2,000 feet AGL. But even at that altitude there is no guarantee of an aircraft's safe passage. On a clear and unobstructed day, ducks can be seen at 5,000 feet! Just ask any hunter. Geese, on the other hand, have been spotted, and occasionally struck, at altitudes over 15,000 feet AGL. Table 9 in the FAA National Wildlife Strike Database Serial Report Number 12 titled, Wildlife Strikes to Civil Aircraft in the United States 1990-2005, reported that although the majority of the strikes were below 500 feet above ground level, 13 strikes were reported above 20,000 feet and one was reported above 30,000 feet. At these altitudes, how many pilots out there can say they are always looking out for birds? The government has diagrams showing the major migratory routes used each year by migratory birds. During the seasonal migrations, aircraft are particularly vulnerable when operating in or near those areas.

There are locations in California that are south of Bakersfield and north of Los Angeles that are the home territory of the California condor. I have had the opportunity to see one in flight! Picture a bird that can have a wingspan nine feet or greater and weighs from 17 to 25 pounds according to the U.S. Fish and Wildlife Service's Internet condor Web site. An impact with one of these could ruin anyone's day, and it would not do the condor any good either!


What other problems are out there in the wildlife areas that are a concern for pilots and aircraft? It is the same concern we have when flying into airports that have animal life in the area. From islands such as Nantucket to the northern reaches of Maine to the plains of Texas to Central Florida to the Seattle area, wildlife exists.

Deer, fox, coyotes, alligators, elk, moose, rabbits, wild dogs, and even bears are a danger to aircraft operations at airports. Day or night, but especially at night, these creatures can run into the path of aircraft landing or taking off. So, what can pilots do to mitigate an encounter of this nature? For these land creatures the safety issues fall into two categories.

During the day, the pilot must be vigilant, listen to the radio, and talk to other pilots on the local airport frequency asking if they have seen or encountered any wildlife. During this time period, the animal collisions are most often caused by animals running into the aircraft path because they were frightened from there hiding space.

Nighttime provides it's own unique problems. Even towered and fenced airports can have "guests" visiting the runways and taxiways! Uncontrolled airports in rural areas are the most dangerous. Fences provide minimal separation and human habitat is limited immediately around the airport. People living around the airport actually help minimize large animal activity.

Every environment has its own concerns, issues, and problems. In many cases, the same precautions work. These following suggestions been garnered from many experienced pilots flying around and near wildlife of all sorts from California to Maine and all points in between. Here are several actions you may want to consider in mitigating wildlife encounters.

For birds of all shapes, sizes, and numbers:

  • Keep as many external lights on as you have on the aircraft. For some strange reason no one has been able to fully explain, birds "sense" or see the aircraft lights and try to avoid them.
  • Unless close to the ground, pull up and gain altitude whenever possible around the birds. They will normally dive down to avoid the aircraft! When they know you are there and have not been surprised (as when the aircraft pops out of a cloud or fog bank right into a flight of geese) birds do their best to avoid you.
  • Allow more then the minimum recommended altitude over bird sanctuaries/refuges/national parks. By giving up more altitude, the aircraft has a larger buffer zone, which provides more reaction time. The more time the pilot has the better the chance to mitigate or avoid an unplanned encounter.
  • Whenever possible, when you know you are going to be flying around birds, try to wear protective eyewear. Even a small piece of debris can cause a major problem with your eyes. For those four-legged wildlife (deer, elk, moose, fox, coyote, rabbits, wild dogs, and bear):
  • At airports that have active control towers, during the day report any animal spotted in the airport environment. The tower personnel will pass the information to the airport manager's office, which will send someone in a vehicle to chase critter away.
  • At non-towered airports, if during the day an animal is spotted inside the perimeter, contact the fixed based operator (FBO). Someone may be available to chase the animal from the airport boundaries. Also listen to the radio at least 10 nautical miles out. There may be someone ahead of you who has already spotted critters.
  • During night operations, the FBO is still your best source of information. If no one is around, then carefully and safely as you can, announce your intentions. Before takeoff, taxi down the runway to try and scare any animal around the runway away. When landing, make a low fly-by. This will allow the pilot to see what may be on the runway and, hopefully, scare away any critter grazing along side the runway.

The best advice in any case is to be cautious. There are times of the year when it pays to be extraordinarily cautious. During mating season the male deer, elk, and moose do strange things. Males challenge other males, chase female, and scatter the young. Even a small herd of deer calmly grazing in a field a good distance from the runway can scatter and run into the path of the aircraft when two males are fighting. Not only is the herd scattered, but also all the smaller creatures in the area run from the clashing males.

Some of nature's own do not fear aircraft! A case in point was an encounter I had with a bear. While on final approach to an airport in northern Maine, I observed a large bear sitting on the edge of the runway. As I watched, the bear was enjoying blueberries from several bushes that were growing wild along side the runway.

Two low passes were made. The first did not even cause the bear to look up. The second pass did cause a passing glance, but no other movement. A call was made to the FBO after the first pass and by the time the second pass was completed, a car was sent to try and chase this very large obstacle from the runway. It took three cars over 20 minutes to distract the bear from the berries. Or, the berries were gone by then and the bear was ready to leave.

There are times a change of course is not possible. When flying over or near a national park, sanctuary, or refuge, please try to fly higher than the altitudes posted. Whenever possible, navigate around these areas. You can take actions to mitigate potential encounters with wildlife.

To avoid tangling with wildlife, pilots should be extra vigilant when taking off or landing and do everything possible to make the aircraft more visible or make sufficient noise to scare the critters away from the aircraft path. Every pilot needs to be aware of possibility of critters running into harms way. Those small "yellow lights" blinking out there may be an animal's eyes reflecting your aircraft lights and this member of nature could be responsible for ruining your day.

Check the sectional charts. Mark national parks and wildlife areas! Avoid these areas whenever possible. When operating in and around them, please be cognizant and maintain full alert for the creatures that live in the area.

Al Peyus is an Aviation Safety Inspector in Flight Standards General Aviation and Commercial Division.

The Airport Wildlife Hazard Mitigation homepage can be found at It also contains information on how to report bird strikes.

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