“The current certification standards for turbine engine (60 inch and 100 inch size) testing are as follows: an engine must be able to withstand the ingestion of 16 small birds (3 oz. each); 8 medium birds (1.5 lbs each); or 1 large bird (4 lbs) (Eschenfelder 2000). Turbine engines are not required to be able to withstand the ingestion of a bird larger than 4 pounds. Eschenfelder (2000) concluded that these engine ingestion standards may be inadequate because they do not reflect the sizes and numbers of birds encountered in actual birdstrike incidents.” (Portland International Airport Wildlife Hazard Management Plan, 2009 Update)While manufacturers are responsible for the safety of their aircraft in such collisions, airports are tasked with the goal of preventing them in the first place.
According to the Portland International Airport Wildlife Hazard Management Plan (WHMP), “Between 1990 and 2007, 82,057 wildlife strikes involving civil aircraft were reported to the FAA.” One study reported, “ . . . 197 human injuries and 11 fatalities nationwide resulting from wildlife strikes between 1990 and 2007.” This, resulting in almost $100 million in damages and over $30 million in associated costs (chewing electrical cables, damaging infrastructure, etc.) annually industrywide.
"Wildlife strike" sounds as if the aircraft industry is under attack when we just get in each other’s way. That's what happens when you build an airport where animals live. When airplanes and wildlife try to occupy the same airspace at the same time, the wildlife pretty much loses.
And, so, Portland International Airport (PDX) has a Wildlife Department. And, a Wildlife Hazard Management Plan.
I read Portland’s Wildlife Hazard Management Plan and found it very interesting for the extent to which considerations must be made in order to avoid wildlife collisions. First and foremost, they must control the food, water, and shelter that attracts wildlife to the airport. To do this they must consider landscaping (which plants can be planted and where); grass length and mowing schedules; grasshopper control; man-made structures that attract nesting opportunities; mitigation to relocate animal populations to more desirable, and less dangerous, places; raptor tagging and tracking; conforming to the myriad federal, state, and local regulations (you can't even imagine); and, coordinating with various agencies and wildlife experts such as the Audubon Society.
I found the report interesting because I never before considered how much went into avoiding animal collisions at airports. Here are several excerpts:
- Between January 1998 and December 2008, 752 bird strikes and 4 coyote strikes were reported at PDX.
- Raptors ... were the most frequently struck group of birds . . . .
- . . . the red-tailed hawk is currently the number one wildlife species of concern at PDX.
- Portland International Airport (PDX) is the 34th largest airport in the country and home to the 142nd Fighter Wing of the Oregon Air National Guard. Bordered on 3 sides by open water features, located on a major migratory flyway and at the confluence of 2 major river systems, PDX is located in a region rich in avian wildlife.
- Hazing and harassment are the primary means used to clear wildlife species of concern from the airfield to allow for safe aircraft operations. Techniques currently used to haze birds include pyrotechnic devices (e.g., shell launching pistols, 12-gauge shotguns), remote controlled propane cannons, other auditory frightening devices (e.g., vehicle air horns and sirens), visual deterrents (e.g., green laser), paintball markers, and bean bags consisting of a 2 inch square heavy cloth bag filled with lead pellets contained in a 12-gauge shotgun shell (used primarily for coyotes).
- There is no record of a cat ever being struck by aircraft at PDX.
- There have been numerous occasions when stray dogs, or escapees from airline carriers, have run loose across the airfield before they could be caught.
- In order to effectively reach all areas of the airfield, wildlife control vehicles are all-wheel drive capable with the ability to communicate, via radios, with other airport assets and with the Air Traffic Control Tower. In addition, each vehicle is equipped with air horns, sirens and spotlights. Vehicles used primarily for airfield patrols are also equipped with pyrotechnic scaring devices, such as a shell-launching pistol and/or a 12-gauge shotgun.
- Most studies show that a compromise of 7 to 12 inches works best at deterring both small and large bird species. The Wildlife Manager will continue to follow the most recent grass height studies. . . .
- To avoid attracting wildlife species of concern near the runways, grass within a safety area around the runways will be mowed only at night with the runway closed.
- The thatch that remains after mowing also influences gray-tailed vole populations, a major prey species for many birds of concern at PDX, in ways not yet clearly understood. PDX will continue to investigate the dynamic relationship between use of the airfield by wildlife species of concern and grass mowing.
- 750 acres of mowed grass that lies within the fenced perimeter portion of the Primary Zone (the area within the airfield perimeter fence, a 300-foot buffer around the perimeter fence, and the runway protection zones (RPZs) located at the end of each runway. )
- ... the Port initiated a grasshopper control program in 2008. . . . surface numbers of earthworms in the Primary Zone are monitored by Operations Department personnel.
Who knew? (Pilots, maybe, but not me!)