T-38 og bird strikes

Pentagon

A Persistent (Feathered) Threat to U.S. Air Superiority

Bird collisions have plagued the Air Force’s T-38 trainer for more than 40 years

By Mark Thompson @MarkThompson_DCNov. 04, 2013

Air Force photo

The T-38, shown here over Edwards Air Force Base in California, has been colliding with birds for more than 40 years

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Air Force pilots flying the T-38 Talon can rest easy, knowing that their cockpit canopy can survive hitting a 4-lb. bird at 190 m.p.h.
Unfortunately, the Northrop supersonic jet trainer has a top speed of 812 m.p.h.
“To my knowledge, the training planes are the only ones in the Air Force fast enough to make a bird strike lethal, and with a windshield too flimsy to deflect one,” a onetime Air Force pilot has written. “I think they still haven’t fixed that problem.”
Indeed, after 43 years of trying to solve the problem, the Air Force is planning to try, once again.
The Air Force has long had a program to reduce collisions between its planes and the sky’s original inhabitants: BASH, which is short for the Bird/Wildlife Aircraft Strike Hazard program. Midair collisions between birds and Air Force aircraft have destroyed 39 planes and killed 33 airmen since 1973. Bird strikes have been a problem for aircraft since Calbraith Rodgers’ Model EX Wright Pusher flew into a Larus californicus off the California coast in 1912, dooming all three.
“Approximately 500 bird strikes occur each year in Air Training Command with over half of these on the T-38,” a 1992 Air Force report noted. “During climbs, cruise, and descents below 10,000-feet the T-38 is normally flown at speeds of 240-to-300 knots which presents a bird strike hazard by larger birds to the pilots.”
So it announced on Oct. 31 that it was going to try anew. The service is seeking “comments and identify potential sources, materials, timeframe, and approximate costs to redesign, test, and produce 550 T-38 forward canopy transparencies to increase bird strike capability.” The move follows a T-38 crash on July 19 in Texas triggered by a canopy bird strike. Both pilots safely ejected. In a related action to improve T-38 safety, the Air Force is spending $184 million on upgraded ejection seats for the fleet.

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“The current 0.23 inch thick stretched acrylic transparency can resist a 4-pound bird impact at 165 knots which does not offer a capability to resist significant bird impacts, and has resulted in the loss of six (6) aircraft and two pilot fatalities,” the service acknowledged. “Numerous attempts since 1970 were made to evaluate existing materials and redesign a transparency that could withstand a bird impact of 4 pounds at 400 knots.” Air Force Captain Theodore Freeman was the first astronaut killed in training, when a Canadian snow goose shattered his T-38 canopy while landing in Houston, on Oct. 31 — Halloween, again — 1964.
Previous efforts have foundered because they’d require expensive cockpit modifications to the twin-engine, two-seat supersonic jet. “Although it would increase the level of bird impact protection,” the Air Force said, “the proposal was cancelled due to the high cost of the modification.”
In part, that’s because in past efforts, the Air Force required a pilot to be able to blast through the cockpit canopy as a last-ditch means of bailing out.

“Combining efficient bird strike protection and TTC [Through-The-Canopy] ejection are novel and contradictory requirements,” a 1990 Air Force study noted, “since the tough materials which resist bird penetrations also resist ‘punch through’ ejection.”
But the latest effort, the Air Force said, “does not require the retention of Through-The-Canopy (TTC) ejection capability” because the new ejection system blows off the canopy intact. The service hopes to “take advantage of new technology to fix the threat” posed by avian missiles, an Air Force general says.
After spending 43 years wrestling with the problem, the Air Force suddenly seems in a rush. In its Halloween announcement, it said it wanted proposals by Nov. 27. Speaking of birds, that’s the day before Thanksgiving.