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

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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

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.

“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.

23 comments
Joe19366
Joe19366

I cant believe 1" inch thick lexan cant do the job? is the airforce too cheap to use it? Is lexan (dupont?) not juiced in with the right politicians/state or not paying the right "campaign contributions to get in to this bid? Acrylic is always known as low cost material... if you had "the hulk" imprisoned in a fish bowl style cell - would you want acrylic or lexan!!! if i hit acrylic with a hammer its gunna crack and break - especially .23 inches thick of it!!!


I'd bet 1 inch thick lexan can take an ak 47 round  no problem - if not a .50 bmg... they can also test the hell out of it by sending birds down an airtube at 1000mph to make sure the canopy will take the hit...

kingofthenet
kingofthenet

I think something that deforms but does not break could work.

tomakay1
tomakay1

Train birds to drop bombs, problem solved.

ptmuldoon
ptmuldoon

I am know expert on birds, but what about the simple ability for the plane to emit an sound wave that any bird would typically not like and would get out of the way?

WobbLes
WobbLes

or maybe move your training bases to area with less birds? Oh wait, you closed most of those in 1989....

dogyear
dogyear

"Transparent aluminum."

DavidWelch
DavidWelch

I wonder why the solution isn't as simple as this. With all the high tech digital camera technology available today, why does the pilot need a transparent windshield through which to look? I may be thinking a little too sci fi into the future, but spaceships like the Starship Enterprise don't have windshields. They have display screens that project a forward (any direction, really) view from the ship.

popcornmaltese
popcornmaltese

RolandDelhomme Thank you for this authoritative supplement. My dad, who was an Army Air Corps B-24 pilot, managed to avoid bird strikes (not so with flak!) but he told me that a crow hit the windshield of his 1938 Buick when he was going 90 MPH. The windshield was undamaged! 

JustUsBikers
JustUsBikers

I guess hi tech planes don't need missiles to bring them down.   Just let loose a bunch of birds!

RolandDelhomme
RolandDelhomme

Not just the T-38; as too many other Air Force pilots and others can attest. Even the F-16 canopy has seen upgrade. It's not just pentration of the canopy that poses a direct, forward hemisphere threat to a pilot, but also the propagation of a wave induced by impact, which can have sufficient amplitude to actually contact a pilot's helmet and transfer sufficient force to incapacitate, within milliseconds. A sharp salute to fallen friends, and the good folks working to mitigate avian hazards, in all forms, to military and civil aviation. USAF bird strike experts reach out to civil aviation continuously, and share much valuable information, much of it quite surprising; for instance, the correct mowing height for grass at an airfield is not low, but rather higher-it disrupts the birds and their ability to communicate as a flock, thus rendering the taller grass less hospitable. One commander ignored this advice, and horrible loss of life ensued due to multiple birdstrikes on an aircraft operating at a low cut airfield, after advice to let the grass grow taller.Flysafe, gang!

elhamb3166
elhamb3166

This does not seem to be an insoluble problem.  Ejection is straight up through the canopy.  Bird impacts are presumably happening straight on to the front of the canopy.  Solution:  Two different thicknesses and strengths of materials used in the canopy.  

Note to Air Force:  Put the thick, strong material on the front of the canopy, the thin, weaker material on the top.

JohnPhuNguyen
JohnPhuNguyen

@Joe19366 As stated in the article, the Through the Canopy ejection method contradicted with the goal of protecting against bird impacts. Also, Lexan has poor visibility characteristics. It scratches easily, bends under temperature changes, diffuses light, and yellows as it absorbs ultraviolet rays. Unfortunately for aircraft, ultraviolet rays are much more intense in the air than what we're used to on the ground. Lexan will never be used in aeronautical applications.

LesClemens
LesClemens

@kingofthenet I disagree, at that speed a deforming material will not have the time to move. It will be penetrated. You need to dump the "through the canopy" ejection. Make the rear canopy a separate section that is removed during ejection and thicken up the forward canopy. Money is the issue????? What is a pilots life worth? idiots. 

jaredddbrown
jaredddbrown

@ptmuldoon Because the bird wouldn't even have time to hear it, process the sound, and move before the jet had plowed into it

The jets are breaking the sound barrier.  

monokit
monokit

@DavidWelch 

Samsung can make curved screens (tech's actually pretty new, won't be mainstream for a while yet), and we can connect them to cameras on the outside of an armoured canopy. That bit's easy.

The problems only start there though. Put a CRT on the shelf next to an LCD screen. Run them both from the same video source - something that changes quickly, like a music video. What do you see?

The CRT screen updates almost immediately; the LCD screen has small delay before updating its image. In other words, the LCD appears to a delayed feed. In an aircraft or car this delay would be dangerous, as it adds to your reaction time.

Add to that the heat put out by the screens, the additional power draw (reduced operating range) of both the screens and your now increased cooling requirements, and the problem of making a curved screen and camera network resilient enough to survive both the shocks and g-forces of combat flight, and it's suddenly a much harder problem.

There's one other problem that can't be solved easily - to make this work, you're projecting a 3d image (the world outside) onto a curved 2d plane (the canopy), with the pilots head moving freely around inside the canopy. He's lost his perception of depth (dangerous, especially on landing), and there's going to be a lot of distortion as his head moves around.


Better solution would be a 3d camera on a ball joint connected to something akin to the oculus rift for the pilot - solves the depth & distortion issues, but you'd need a much lighter and much higher resolution screen than currently available for it to work. There's also the problem of an external ball camera that can survive ACM and not interfere with the planes aerodynamics.


The problems aren't unsolvable, the solutions just aren't practical yet.

EricNorthman
EricNorthman

@DavidWelch There aren't many pilots out there that would fly a jet like that. They want and need to see the area around them in a 150 deg+ arc, and no digital screen is going to replicate that appropriately. The previously aforementioned fact that there is no real way for the birds to get out of the way in time is compounded by the fact that the T-38 is a very small cross-sectioned jet, one of the smallest in our, or anyone's inventory. The problem is as big for the bird seeing a T-38 as it is for the pilot seeing the bird. I was stationed at Eglin AFB in Fla for 10 years, and only had a few birdstrikes during that time. The canopy of an F-15 though is pretty tough and can withstand a pretty good hit. Had to clean the remnants off of my jet's canopy a few times though.

KCPhil
KCPhil

@JustUsBikers   The T-38 is not really all that high tech, by today's standards.  It's a trainer that's been in use since 1961.  But - I suspect I'm being too literal.

EricNorthman
EricNorthman

@elhamb3166 We do not eject *thru* a canopy. The canopy is shot backwards at about 30 deg and after it is taken away by the slipstream, then the seats are ejected. At least, that's the way it should happen. "Top Gun" is not real life, those canopies are long gone by the time the seat rockets fire.

ARTRaveler
ARTRaveler

@LesClemens @kingofthenet If it costs a million dollars to train a pilot to effective war capability, just how much are you willing to spend to have people survive their training.  Folks, this is a "no brainer" to at least getting ideas out for wind tunnel testing.  You wasted billions on a fighter, the F-35 that is a loser, can fly in the rain, and kills pilots but at least it isn't being used every day.  Get this problem fixed, starting with the best industry minds you can find. And get away from aircraft companies and look at people like DuPont who make the acrylics and their competitors.  There are bound to be industrial uses beyond the military.

boguem
boguem

@jaredddbrown @ptmuldoon Not at the altitudes at which you normally find birds, though that's irrelevant.  Even at the stated 240-300 knots they fly within the birds' territory, birds wouldn't have time to react.  Plus, how are you going to get an entire flock to react in the same direction?  If they scattered, you'd just have a wider area for possible strikes.