Most people appreciate animals, but not on and around airports. Addison Airport has documented 130 wildlife strikes since 1990, and 10 of them resulted in substantial damage to aircraft. That might not seem like a lot, but just one incident, like the airliner that landed in the Hudson River after it ran into a couple of geese, defines the consequences of the risk that the FAA encourages every pilot and airport to consider and mitigate.
The wildlife risk at every airport depends on the habitat on and around it. Dedicated to providing the highest level of safety possible for tens of thousands of aircraft that use the airport each year, Addison invested government funding in an intensive survey of its habitat, said Joe McAnally, Addison’s operations manager, who is responsible for everything inside the airport fence that affects aircraft operations and safety.
The survey is “a condition report of our current wildlife situation.” Over the past year, wildlife biologist Scott Florin from Kleinfelder, an engineering firm that specializes in airports, spent several days each month making morning, midday, and early evening observations across the habitat that extends 5 miles from the airport. In all, he recorded 59 different bird species and four animal types.
“He saw mostly doves and pigeons, but the airport is also home to huge flocks of starlings that often take flight in large flocks,” said McAnally. The survey also revealed raptors like Red-tailed Hawks and American Kestrels that feed on smaller critters. The airport is inundated with jackrabbits that normally don’t interfere with aircraft, but do serve as a food source for the occasional coyote that makes its way to the airport.
TX DOT and the FAA are now reviewing Florin’s report of his yearlong wildlife analysis. It includes “general recommendations, like habitat modification, for mitigating wildlife on the airport,” said McAnally. Specific changes to reduce the possibility of an unfortunate interaction between an airplane and critter will come with the airport’s wildlife management plan, which Kleinfelder is now drafting.
Habitat changes make the airport unattractive to birds and animals. One idea the airport is already considering is letting the grass grow taller than the traditional 2 inches, perhaps as tall as six to 10 inches. “Longer grass makes it difficult for the birds to see one another when they land. They don’t like that.” Denying animals’ airport access with grates on storm water culvers is another consideration.
Wildlife on and around the airport changes constantly, said McAnally, so mitigating the hazard is a continuous process that begins with reporting. He urges anyone who’s involved in or witnesses a wildlife strike to report it. This information helps the FAA track trends and determines hazards by species, and it helps the airport’s wildlife program better identify, understand, and reduce the threat. It doesn’t take long, and there’s an app for it. (See: Witness a Wildlife Strike at Addison Airport? Report it Using Your Mobile Device.)
On their cross-country peregrinations, Addison Airport is a frequent stop for U.S. Navy F-18s. When the weather and traffic at the airport allow, they arrive in a fashion unlike that of civilian aircraft. The jet (or jets) enter the traffic pattern by flying directly over the runway, reverse their direction with a snappy 180-degree turn in a steep bank, followed by another 180-degree turn that puts them on final approach to the runway.
It may look like showboating, but it’s the safest, most efficient way to get a number of airplanes on the ground in the shortest amount of time and it minimizes the time the jet flies at slower speeds. That snappy turn is the break, and the steep bank angle increase the g forces on the airplane, which gobbles up its forward energy, or speed.
As described by the F-18 NATOPS (aircraft operating flight) manual, at the break the pilot reduces thrust and deploys the speed brake as needed during the downwind turn. “As the airspeed decreases through 250 knots, lower the landing gear and place the FLAP switch to FULL and ensure that speed brake is retracted.”
From their first day of training, naval aviators are taught to control airspeed by angle of attack (AOA), which is controlled by pitching the nose up or down. Power determines altitude; with a set airspeed (AOA), adding power results in a climb and reducing it establishes a descent. If the jet sinks below the desired final approach glide path, the aviator corrects this by adding power, which is why the engines’ volume sometimes changes on final approach.
An AOA indicator in the aviator’s field of view coincides with the desired on-speed for landing. NATOPS says: “On-speed without external stores and 2,000 pounds of internal fuel is about 125 knots [144 mph]. Add about 2.5 knots for each 1,000 pounds increase in fuel and stores.” Final approach concludes with “a firm touchdown at least 500 feet past the runway threshold.”