What do you do with a cannon that fires dead birds?

I’m in the violently green hills outside Peebles, Ohio, just north of the Kentucky border, on what appears to be a giant nature preserve. Or it would be, were it not for the sheer number of powerful jet engines, some of which are waiting their turns to have bird carcasses — 2.5 pounds, 4 pounds, 6 pounds, and 8 pounds, all pre-euthanized — hurled into their fan blades. The birds are from local suppliers that are certified by the Department of Natural Resources; GE then x-rays them to make sure they haven’t been shot. An approved bird is then loaded into a cannon device and shot into the engine. I asked about video for posting to this site, but was warned that other people find it disturbing.

The video is disturbing. It is also very cool.

Peebles is home to GE Aviation’s Peebles Test Center. Sitting outside "Disneyland for geeks" is a crumpled white car with a sign next to it: "Don’t text and drive." It’s a real car that really crashed when its driver was texting, says Brian De Bruin, the plant leader at Peebles ("If this is Disneyland for geeks, I guess that makes me Mickey Mouse," he says later). Texting and driving is a common problem in rural Adams County, Ohio, the home of the 7,000-acre reserve that tests 1,600 engines a year.

The state-of-the-art facility is located in the middle of nowhere to avoid noise pollution. Hawks lazily float on air currents above us, apparently unperturbed by the occasional sound of engines. Peebles was initially opened in 1954, and was intended to test rockets, though that never actually happened. It acquired its modern function in 1965, when GE ran its first test of the TF39 engine there that would eventually power the Air Force’s Lockheed C-5 Galaxy transport aircraft.

Security is tight, though the guards are friendly — I arrive a little early and am directed to wait for Jamie Jewell, the spokeswoman for CFM, GE’s joint venture with French company Snecma (which startles me every time someone says it aloud — I cannot help but hear the mondegreen "smegma"). Jewell arrives with De Bruin, and we all pile into a minivan. I am very much hoping that I will be able to witness engine tests, but first, Jewell and Chris Nye, marketing manager for Leap, walk me through a video of the brand-new Leap engines — turbofans that will find their way into next-generation midsize airliners from Airbus, Boeing, and China’s COMAC. GE currently is producing one engine every four hours.

The Leap testing, conducted primarily at Peebles, is meant to be complete by the end of this year. There are, of course, the FAA standards — and meeting them means that GE engines are cleared for China as well. There’s the over-torque test and teardown inspection, meant to give regulators an idea of the wear and tear the engines may face during their lifetimes; during these tests, the engines experience extreme conditions, meant to determine their durability. There’s the vibration test and the corrosion test; the thermal fatigue test and damage tolerance test; the crosswinds test and acoustic tests. Then there are the fun tests: birds, volcanic ash, dust ingestion, and hail.

But Leap is still undergoing certification testing, the bulk of which is expected to be done by the end of this year. They’ve already finished the bird test and another test, the "blade-out," which I think I like even better than the bird test. Here’s what a blade-out is: a thumb-sized amount of the explosive C-4 is attached to a blade’s base. Once the engine is running at full power, the C-4 explodes, knocking out the blade. The test is to show the engine can contain the lost blade — no one wants it to go careening into the passengers onboard the plane — and that the engine won’t catch fire.

Once the engine is running at full power, the C-4 explodes, knocking out the blade

It’s De Bruin’s least favorite test because it destroys the engine. "That makes me sad," he says.

The engines have to be durable enough to stand this kind of rough treatment, but they also must be light. Engines are, of course, hung under the wing — where they create drag, so engines must generate the needed thrust to get the airplane off the ground while minimizing weight penalties — the thrust-to-weight ratio is seven to one on the Leap engines. And the heavier the engine and the plane, the more fuel it burns. Fuel is expensive, accounting for more than a quarter of airlines’ operating costs — the single largest cost most airlines have. In the interest of saving weight, Snecma uses 11 miles of carbon fiber woven into each of its Leap blades, like a T-shirt woven on a loom, with a titanium leading edge. That’s for the birds — it’s essentially a knifeblade. The engine also boasts ceramic components to improve fuel performance and 3D-printed fuel nozzles.

Once I’ve been briefed on the Leap engine, it’s time for a tour of the facilities. Engines are frequently assembled at Peebles, since a shipping route through the Cumberland Gap is easier for trucks with lower weight — a fully assembled engine is heavy, and would limit shipping to a few daylight hours. (The GE90–115B, which is found on Boeing 777s, weighs 18,000 pounds and is about 11 feet in diameter.) So the production engines are brought to Peebles in pieces and then put together and tested for two days before being shipped for placement on planes. We enter a warehouse that exists for this purpose; Depeche Mode is playing over the speaker system.

Next, we head to a frankly enormous indoor testing facility — one that cost $40 million to build. The sites are like oversized garages, with cranes above to help maneuver engines into place. Acoustic tests take place there, but so do a lot of the tests that take place outdoors — the idea was, essentially, to create a site that wouldn’t be impacted by the weather. Overall, there are four enclosed test sites and seven open ones.

"Now, we’re going to go up the hill," De Bruin says. As we begin to wind up what is, indeed, a very tall hill, he points out the original rocket testing stand, as well as what he calls "the holler" — Appalachian slang for a hollow between two hills (or mountains, as the case may be). It is littered with old engines and parts. If anything goes wrong on an engine in production — or if a customer or the FAA has important questions — these old engines can be pulled out to be tested. It is far and away the most expensive holler I have ever witnessed.

At the top of the hill are a series of open test sites. At one, a massive machine makes ice sheets and hail to be tossed into the roaring turbofans — and if the hail isn’t large enough for testing specs, it’s melted and reformed. This site is out of production in the summertime, since the heat melts the ice used for testing. Getting the ice sheets into the engines is particularly tricky: engineers must hurl the non-aerodynamic slabs at the engines and hope for the best. It’s like trying to throw a leaf into a garbage can from several feet away, De Bruin says.

Very large honeycombed structures — they’re called turbulence control structures and inevitably bring to mind Epcot Center — litter the sites. These oversized golf balls essentially help control the airflow into engines during testing. Nearby, De Bruin points out a modified cherrypicker — engineers had trouble using the regular ones, and so they made a DIY version by fastening the hydraulic system to a flatbed truck. Though they’d built it, the engineers were too spooked to use it — but it served as a prototype for models that now dot Peebles.

In fact, I didn’t see any live engine tests while I was on-site, which seemed like a shame. Four Leap engines were scheduled to be tested, and while I saw some of them in the rigs, I didn’t see the tests themselves — apparently I arrived just in time for a lunch break and a shift change. What I did see was a video, and a 3D rendering of the Leap engine, and many of the customized test rigs. In fact, I had to spend a lot of quality time hearing facts about the new Leap engine. What I discovered was that my time as a pharmaceutical and biotechnology reporter has made me jaded; anything ready for its commercial launch I automatically regard as old and busted; the new hotness — the thing that could tank the company if anything goes wrong — is usually a few phases of testing behind.

De Bruin and Jewell return me to the guardhouse — some locals call Peebles the "Area 51 of Ohio" for its tight security — and I get back into my car. The sun is shining, the birds are singing, and somewhere, very close to where I am turning the key in my ignition, a jet engine is about to be abused.

Correction: This article originally stated one engine will be produced every five hours; in fact, it is four. In addition, Snecma, not GE, produces the carbon fiber fan blades.