Nature's Protected Areas: A Potential Risk To Aircraft
by Al Peyus
Reprinted with permission from FAA
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
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
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
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
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
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
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
BIRDS ARE NOT THE ONLY RISK
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
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
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.
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
- 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.
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
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
The Airport Wildlife Hazard
Mitigation homepage can be found at
It also contains information on how to report bird strikes.