As we practice our license to learn, some hazards demand our frequent attention: Traffic, weather and terrain are the top three. They present varying levels of predictability, and a huge amount of brain power and economic investment has been poured into keeping pilots out of the teeth of these hazards. But what about the less predictable living hazards that share the airport-and sky-with us? Plenty of critters live on and around airports, and as for sharing the sky with birds, well, they got there first.
A TERN FOR THE WORSE
Sometime in the 1980s, a Japan Airlines-bound ab initio student at Napa Airport, Calif., (APC) had a rough time understanding the tower controllers by-the-book NOTAM. She warned, “Aircraft in the vicinity, be aware of large waterborne fowl in and around the airport environment.” After several futile rounds of the hapless student pilot requesting that she say again, she finally bellowed, “Birds! We have birds on the runway!”
Birds in the aviating environment are far from the cute critters alighting on Cinderellas hand. A brown pelican, for instance, can pack a punch, weighing up to six pounds (and lets hope you never encounter the 33-pound Dalmatian pelican). Turkey vultures weigh up to 10 pounds; however, the mass generated by a closure rate greater than your en route cruising speed can be incredibly destructive. Size doesnt always matter: The tiny starling is a feathered bullet, with a body 27 percent more dense than the herring gull.
The Bird Strike Committee USA (BSC-USA) is a volunteer organization comprising representatives from the FAA, the U.S. Department of Agriculture, the Department of Defense, as well as aviation industry and airport management. Formed to identify and analyze wildlife strike data in the interest of safety, BSC-USA notes that bird and wildlife strikes cause in excess of $600 million in damage to civil and military aviation in the United States alone. Since 1988, more than 219 people have been killed worldwide as a result. In 2007, over 7600 bird and other wildlife strikes were reported for civil aircraft in the U.S., and the guilty parties are dominated by waterfowl, gulls and raptors, representing 75 percent of the reported bird strikes between 1990-2007.
The BCA-USA presented a best management practices report in June 2007, making 11 recommendations to mitigate the hazards posed by wildlife in the aviation environment. (For the entire report, check their Web site: www.birdstrike.org/meetings/BMP.htm#_Toc169661993.) The reports high points include assigning responsibility to an airport official to implement a wildlife management program, and to become involved in local planning and land use decisions within five miles of the airport that could attract hazardous wildlife. Planning bodies, while practiced at applying the appropriate municipal codes to their decision-making, do not always have the benefit of aviation-specific information during that process.
Airport management is also charged with habitat management, such as netting bodies of water or replacing attractive plantings with foliage that animals dont like as much. The recommendations also identify the use of dogs, raptors and trained personnel with firearms to disperse especially persistent flying hazards.
The report cautions airport staff cannot be everywhere (thats Supermans job), and it takes time for wildlife specialists to react to a given hazard. Thats especially true at airports near the water. Carlo Aclan, an ATP who flew out of San Carlos, Calif., (KSQL) for many years, recalled several occasions when he saw a flock of seagulls near short final, and called the tower to dispatch the seagull-shooing pickup truck while he stayed in the pattern.
Of course, pilots should implement their own risk assessments, and delay takeoff or landing if possible when hazardous wildlife is encroaching in the airport operating environment. Its the “if possible” that drives the majority of incidents and accidents caused by birds and animals.
The BSC-USA notes that 56,000 bird strikes to U.S. civil aircraft between 1990 and 2004 were reported to the FAA, an estimated 20 percent of the total likely number of strikes. Takeoff and landing operations comprised 41 percent of the reported strikes, and 75 percent of strikes occur at or below 500 feet (AGL). Between 1990 and 2003, 1300 strikes were reported as occurring at or above 5000 feet agl. The highest reported strike occurred at 37,000 feet. We presume the bird was cited posthumously for not wearing an oxygen mask.
NEAR THE RUNWAY
According to ICAO, 90 percent of bird strikes occur near airports. A strike during takeoff is a particularly bad addition to an already labor- and brain-intensive operation: High deck angles combined with high power and low speed at low altitude make it imperative to anticipate the unexpected, and to adhere to your appropriate emergency procedures. This is not a good time to try that turnback to the airport.
The U.K.-based General Aviation Safety Council (GASCO), a nonprofit organization that includes AOPA and a number of other groups, advises a thorough preflight, since birds can build a nest overnight. Look for stray pieces of grass or other foliage, and follow up with a close look in the dark nooks of your engine compartment or empennage. A nest near the engine can cause a fire, and one in the tail can interfere with control travel. When taxiing, look for birds on the infield and taxiway; many gulls have a dark back, effectively camouflaging them until you hit them on takeoff. If you do see a large flock, ask ground personnel to disperse them if possible, but dont take the Dirty Harry approach by scaring them away with your aircraft.
Its a good idea to use your landing lights during the departure and approach segments, and if you have windshield heating, its use will make the windshield more pliable and more resistant to shattering. If youre able to see birds while still on approach, go around-they may be gone by the time you start your second approach.
Training for the unexpected can save the day; consider having a conversation with your favorite CFI about the effects of a missing prop on your planes handling. The preflight briefing for your non-flying passengers is important: If youre incapacitated by a bird strike, be sure your passenger can get you on the ground in one piece. Its also a good idea to brief the possibility of losing communications in the cockpit in the event of a bird strike. While your passenger keeps an eye out for other traffic, suggest they include birds in their scan; a non-pilot may not consider birds to be a threat to the safety of your flight.
Allen Wolpert, an ATP who flies out of Danbury, Conn., advises, “Dont make a small accident into a big one. Ive had two bird strikes: One was during a circle-to-land approach out of a low overcast. A flock of birds was sitting just to the right of the runway as I did a close-in circle. I saw the flock lift off and head toward the runway just as I entered the flare. I decided quickly that the safest action was to continue the landing rather than do a go-around, fly into the flock, and potentially have to deal with one or two engine failures. My props cleanly cut the heads off of three or four birds, which then lay dead on the runway.”
AFTER THE STRIKE
If you hit a bird during your takeoff run, abort the takeoff if you have enough runway remaining, then taxi off and shut down. Look closely at the intakes and engines for damage or bird ingestion, as well as for bird pieces blocking your ductwork. Inspect your landing gear and brake lines, as well as your antenna arrays.
If the bird strike occurs when you cannot abort the takeoff, execute the appropriate emergency procedures. If you see birds ahead, try to fly safely above them, as birds will generally dive to avoid a threat. In the event you fly through a flock, or experience a strike, fly the aircraft: Dont let the encounter sucker you into a stall or spin. If you experience any structural damage, check the planes controllability at a safe altitude before trying to land. A broken windshield will increase the wind blast and debris; slow down and put on some sunglasses to protect your eyes. Reviewed your NORDO procedures lately? The blast of the wind may make your transmissions unreadable, presuming you still have your comm antennas.
Once youre on the ground, check your plane for damage, report the bird strike to the FAA and call a mechanic to give your aircraft a good look.
The GASCO advises a collision with even a small bird is closer to a collision with a compact, dense missile. The closure speed between your aircraft and the bird gives it the capability of inflicting substantial damage to your plane. For example, a collision with a two-pound seagull at 105 knots creates an impact force of 4800 pounds.
Bird strikes in cruise have destroyed windshields (sometimes injuring or killing the occupants), broken pitot tubes, shattered props and hammered wings. Wood props are especially vulnerable to breakage, creating a real energy-management and CG problem, although losing a metal prop affects CG more.
Most of the in-flight strikes naturally involve the forward-facing aircraft components, such as propellers, windshields, leading edges of wings and the horizontal stabilizer, and the leading edge of the vertical stab. Sometimes the prop will turn into a bird processor, but the occasional bird will sneak through the spinning blades and keep going into the cockpit. Birds can generally evade a plane cruising at about 90 knots, but above that speed, a strike is more likely. Also, the risk of strikes increases during July and August, as the rookie birds venture from the nest. And remember, birds do fly at night. The chance of actually seeing that bird is low, but keep the thought in the back of your mind. Finally, birds of prey have been known to attack aircraft.
Flight instructor John Diegoli of Hayward, Calif., notes that birds in flight instinctively want to descend if they encounter an aircraft. He suggests waiting them out if possible; he once encountered a bird that was flying so erratically that if he had maneuvered the plane at all, he would have hit the bird. He added that during an associates flight, a duck at her altitude missed the propeller, blasted through the Plexiglas, hit her in the head and ended up in her lap. Fortunately, she wasnt knocked out and was able to land safely.
As fortunate as these pilots were, that kind of pointy mass combined with a high closure speed can be fatal if the soon-to-be-ex-bird draws a bead on you. Diegoli has reacted to a bird strike by ducking sideways behind the panel, which gives him more protection than the Plexiglas would.
Speaking of do-it-yourself Plexi care, aircraft detailer Renny Doyle cautions against abrading your windows so much that a bird strike would cause a break in a thin spot. “If a scratch penetrates halfway through the plastic, Im going to think really carefully before replacing it. An A&P will know-if its more than a fingernail-depth scratch, somebody should look at it.”
While no one has reported a deer strike in cruise (Santas reindeer have TCAS), there are myriad ways that ground-bound animals can make takeoff, landing and taxiing difficult. According to AOPA, second place in the wildlife strike sweepstakes is awarded to deer. The U.S. deer population has increased to 30 million, partly because of lack of natural enemies, and restrictions placed on hunters in the areas near airports. Deer can weigh between 125-200 pounds, and can put a substantial crease in your aircraft.
The FAA reported that between 1990-2007, there were 796 deer strikes in the U.S., most of them occurring at dusk or night; they are particularly active in autumn. They blend into the foliage, and can run up to 30 mph. Yes, deer do freeze in landing lights; if you are safely able, turn your light on and off to break their fixation.
Don Brown, a retired Atlanta Center controller, recalled, “Back in my ramp rat days I got invited on a midnight run to London, Ky. (LOZ), in an Aztec. We landed about one in the morning. Just as the nosewheel touched down, a dog flashed by the landing lights. The pilot instinctively hit the brakes for a split second; fortunately, we missed him. I always remembered that as a controller, and never pressured anybody to cancel in the air on the midshift. Id rather know that they didnt swerve off the runway dodging a deer. Im always surprised how many pilots cancel going into a deserted airport late at night. I wouldnt. Id call after I got on the ground.”
Its a good idea to brief your passengers for potential wildlife strikes, and use the extra sets of eyes to look for animal life while on approach. A loud clearing pass prior to landing will give you a good look at the landing environment, as well as a chance to shoo the wildlife away before returning to land. Be prepared to go around at any time, and practice good landing form, not using up the entire runway-you may need it for a late go-around, a much better alternative to an overrun.
If you experience any kind of wildlife strike, fill out the FAA online Form 5200-7 (wildlife.pr.erau.edu/strikeform/birdstrikeform.php). The FAA estimates 80 percent of all wildlife strikes are unreported, and that the accompanying damage is also underestimated.
The takeaway? Birds and other animals add a few wildcards to the airport and cruise environment: They havent read the FAR/AIM, and dont much care what happens to us or our aircraft. Be ready to go to Plan B quickly, stay ahead of your airplane, and stay focused on the flight until youre shut down.
Cory Emberson is a private pilot with several hundred hours and is a contributing editor to KITPLANES magazine.