KILLER CLAMS? - WHAT'S MAKING THESE SHELL FISH A THREAT TO THE AIR FORCE'S MOST ADVANCED FIGHTER?

  • Published
  • By Tech. Sgt. Russell Wicke
  • Air Combat Command Public Affairs (ACCNS)
Langley Air Force Base, Va. --  Free-falling clams dropped by in-flight birds are regular air-threats to the high-tech F-22 Raptor.

Gulls drop fist-sized mollusks on the Langley Air Force Base, Va., runway to break open the shell-fish appetizer -- nothing personal. But their shelling device just happens to be a convenient launch pad for aircraft in the 1st Fighter Wing.

The gulls remove half their mess, slurping up tender meat from the runway -- but they leave behind hard, brittle seashells for an F-22 to suck up through its engine. Although the Air Force is wildlife friendly, Lt. Col. Lawrence Spinetta, 1st FW safety chief, isn't willing to let a $10.2 million engine go to the birds -- or the clams.

That's why Langley operates an aggressive flight-safety program to mitigate the bird and wildlife aircraft strike hazard, better known as BASH.

"BASH is particularly important for Raptors because they are so expensive," Spinetta said. "If we lose one aircraft, it costs the Air Force and taxpayers $135 million."

Wildlife Biologist Tom Olexa, U.S. Department of Agriculture at the 1st FW, said most wildlife threats to aircraft are birds; although, deer, coyotes, turtles and even clams, are also foreign-object threats.

"A key component of BASH is to ensure the safety for our pilots and aircraft," Olexa said. "But we also want to protect (wildlife) from being struck by our aircraft."

But "aircraft conservation" is a priority on Air Force bases, Spinetta said, because Air Force "birds" belong to taxpayers.

"A little sparrow may not seem like it's a threat to a 60,000-pound aircraft, but it is -- particularly if it gets sucked down the intake," the colonel said.

Even if a bird strike doesn't cause a crash, damages can soar into the millions.

The Federal Aviation Administration claimed birds cost the civil aviation industry about $600 million per year. The Air Force alone coughed up roughly $16 million in 2007 from bird strike damages. Only a few types of birds account for the majority of the damage. Certain species in particular do more than peck at the Air Force wallet.

For example, the turkey vulture alone accounts for nearly 800 strikes and more than $51 million in Air Force flying history, according to Dan Sullivan, Air Force BASH deputy chief and wildlife scientist. It ranks No. 1 in Air Force bird strikes.

However, the most expensive bird is the American White Pelican. In only 18 strikes, this bird accounts for more than $257 million in damages. Sullivan said this cost is attributed to the size and weight of the bird -- a whopping 20 pounds, compared to an average five pounds for the turkey vulture.

"The black vulture and turkey vulture are the greatest threat to Air Force aircraft overall because they are somewhat large and soar at high altitudes -- about 3,000 feet," Sullivan said. "During the day, as the air warms up, they ride a rising thermal draft. Their high altitude makes them hard to detect from the ground."

He added these vultures, among other avian species, are increasing in population because of U.S. conservation efforts.

Other threatening birds at high altitudes include all raptor species. Sullivan said these birds also are increasing in numbers because the United States stopped using dichlorodiphenyltrichloroethane, a pesticide known as DDT. The cessation of DDT use was necessary, he said, because it threatened the once-endangered bald eagle. But an offshoot of this action means the Air Force shares more of its air space.

And sharing air space with birds is a moderate concern to Air Force pilots.

"I think it would be a life-changing event to have a five-pound Canadian goose smash through your windshield at 400 knots," said Spinetta, who is also an F-15 pilot.

No pilot wants to share the cockpit with fowl, but avoiding birds in midair is nearly impossible, Spinetta added.

"It's very difficult (to dodge a bird) at the speeds we're going (350 to 400 mph at low altitude)," said Capt. Ray Thaler, 1st FW F-22 pilot and chief of flight safety. "(With) birds being very small, you never usually see them until the last half-second."

The problem is, he said, a single bird can take out an entire engine or could break through a canopy and hit the pilot. This becomes more serious in single-engine aircraft like the F-16.

Almost nothing can be done, short term, to avoid high-altitude strikes. But Langley's BASH team is heading up a project to track Ospreys, the fifth most-dangerous bird species to aircraft, Spinetta said. He added that there are more than 72 Osprey nests within a 20-mile radius of Langley.

To mitigate the growing threat, the 1st FW, NASA and USDA came up with a unique way to track the Osprey.

"Captured birds were fitted with GPS-capable transmitters ... (that) transmit the altitude, speed and direction of travel of each bird every two hours," Spinetta wrote in an editorial for the Flight Safety Magazine. "As a result, Langley has been able to pinpoint nests and focus its reduction, suppression and prevention efforts to eliminate many Osprey hazards."

The nests are usually relocated to safer areas by USDA members.

Other more traditional techniques for eliminating hazards involve harassing birds on the airfield, Olexa said. He added that the most common tool is simply a combination of pyrotechnics and artificial bird distress calls, known as bioacoustics.

"The trick is to make the airfield less attractive to wildlife," Sullivan said.

He explained that one way is by planting certain grass species that cause an upset stomach to geese. Another example is to avoid planting fruit/nut producing trees. The Langley BASH team also covered tall airfield objects with spiny metal strips or cone-shaped devices to deny perching.

From 1995 to 2000 Langley spent more than $1.6 million in aircraft damage from wildlife strikes. Since they employed the services of USDA in 2001, there was a 98 percent reduction in cost. From 2001 to 2006 wildlife strikes accounted for a mere $31,000.

"Pocket change," Spinetta said, compared to the previous five years' cost.

And that's why BASH and USDA Wildlife Services are partnered up -- to save aircraft, pilots, birds ... and maybe even a few clams.