Somewhere high above New Jersey, I yanked the oxygen mask off my face, worried I was about to throw up.

Maj. Jason Markzon, the pilot of our F-16 fighter jet, had just steered the plane through two tight, hard turns, part of an aviation procedure called the G-exercise. A moment later, Markzon—whose Air Force call sign is Flack—abruptly rolled the aircraft on its side, a maneuver known as a knife-edge pass that put the plane’s stubby wings perpendicular to the ground. He brought us back to horizontal, then pulled the plane hard to the right. I groaned.

The crushing turns and fast choppy maneuvers were physically punishing—a roller coaster ride I wanted to end. “Do you mind leveling out?” I asked.

“Rob, how’s it going, man?” Flack asked, his voice coming in through the speakers in my red, white, and blue helmet.

“I do not feel well,” I replied.

We had taken off some 20 minutes earlier, all eight stages of the jet’s afterburners lit and rocketing us down a runway at MacArthur Airport on Long Island. We screamed off the ground and into a partly cloudy blue sky on a windy morning in late May. Moments after becoming airborne, Flack pulled back on the control stick in his right hand, sending us into a 60-degree climb at something north of 400 mph.

The seats on an F-16 are reclined at an angle of 30 degrees, so a 60-degree climb feels like you’re going straight up. We flew to about 10,000 feet. That took all of about 30 seconds and hit us with 5.4 Gs, or more than five times the force of gravity. I weigh around 155 pounds, but at that acceleration, it felt like I weighed more than 800. Flack ended the climb by leveling us out with a slow roll. For just a moment, we were upside down.

We cruised to the Garden State, and Flack made a 90-degree turn, then a brutal 180-degree turn—a hard long pull and a steep bank angle. I experienced 6.2 Gs during the maneuver. (Astronauts typically endure three or four during liftoff, and an F-16 and its pilot can handle nine.) The sudden moves were part of our G-exercise, a standard practice before any flight that might hit the crew with high Gs to ensure that the plane, and anyone aboard, can take the stress. I did not pass.

It’s hard to describe the frightening sensation of pulling heavy Gs. A crushing feeling pushes you back into your seat. You experience difficulty breathing. The force pushes blood away from your eyes and brain, potentially giving you tunnel vision. It’s not unusual for rookies to feel pummeled by the Gs—some even lose consciousness—and shaken to the point of puking from air sickness.

I didn’t vomit. Not then, anyway.

Air Force photo

The plane wrote checks my body couldn’t cash

The Air Force sometimes offers journalists the chance to ride in an F-16 when the Thunderbirds are in town. The team, which is to the Air Force what the Blue Angels, with their F/A-18 jets, are to the Navy, performed in New York in May.

Pilots often refer to the F-16 as “the viper,” a reference to spacecraft that appeared in the original Battlestar Galactica and to the fact that the plane is so maneuverable, it can seem to snap around like the head of a snake. (The official name is “The Fighting Falcon,” but come on: “viper” sounds so much cooler.)

Flack took me up in an F-16D Block 52, a two-seater built in the early 1990s. It features a Pratt & Whitney F100 turbofan engine that produces more than 29,000 pounds of thrust with the afterburner. Hold the throttle wide open and, if you’ve burned off enough fuel to lighten the load, the plane will fly straight up. I was sitting on an Aces 2 ejection seat, which I’d armed before takeoff by moving a small lever.

The Air Force added the F-16 to its fleet in 1979 and the plane remains in service today; the sleek, single-engine aircraft is lighter than Navy fighters and can hit twice the speed of sound. It’s renowned for its agility and ability to accelerate quickly from low speed. “The F-16 was the quintessential dogfighting airplane of the late 20th century,” says retired colonel Mike Torrealday (call sign, T-Day), who flew the aircraft for about 25 years and even ejected out of one over Utah after an engine failure. “It’s probably one of the most physically demanding airplanes to fly.”

Movies like Top Gun can’t convey the brutal physics of piloting a fighter jet that can, as T-Day says, “snap 9 Gs in less than a second.” Pilots are athletes in top physical condition and endure years of training to handle the accelerative forces. This is critically important to avoid a phenomenon called G-LOC (pronounced gee-lock), or G-induced loss of consciousness.

Rob Verger strapping into a F-16 jet
Before the flight. US Air Force Thunderbirds

Before strapping into our viper, Flack and I donned G-suits—a high-waisted garment worn over the flight suit that features a hose connected to an air system in the jet. As pilots experience increasing acceleration, the suit fills with air like a blood pressure cuff, squeezing the legs and abdomen. That prevents blood from pooling in the extremities, keeping it in the chest and head and reducing the risk of losing consciousness.

Even more important than the gear is an exercise called the anti-G-straining maneuver that requires tensing the calves, hamstrings, quads, and glutes while clenching your abs. Imagine sitting in an office chair, pulling your feet backward as you roll and drag yourself forward. That helps blood remain in your core and brain, keeping your lights on and preventing you, as pilots say, from taking a nap. Aviators do this as they quickly inhale and exhale every three seconds or so by making a breathy “keh” sound.

Fighter pilots learn these techniques early on in trainer aircraft and hone them in a centrifuge, learning what it’s like to get it right—and wrong. “You can see somebody almost melt in front of you if they don’t do a correct anti-G-straining maneuver,” says Cheryl Lowry, a retired Air Force colonel and physician who teaches at the University of Texas Medical Branch.

You can’t safely pull a lot of Gs without wearing the suit and doing the exercise. Your heart rate would skyrocket as it fights to keep blood flowing upstairs rather than pooling everywhere else. You’d lose peripheral vision and then the ability to see color before going temporarily blind. “Pretty much immediately after that, you’re in grave danger of having a G-LOC,” Lowry says. When you regain consciousness—if the jet hasn’t crashed—you’ll feel woozy.

Pilots rarely lose consciousness; the Air Force says that statistically, it takes around 200,000 hours of flight time or more to get one G-LOC event. It recorded at least nine incidents in each of the past three years, including a fatality during a Thunderbirds training exercise over Nevada in April, 2018. Maj. Stephen Del Bagno crashed after feeling a max of negative 2 Gs (a situation that can occur if the plane is inverted, sending blood rushing to the head), while flying upside down before going into an 8.5-g dive. The Air Force determined that the “push-pull” effect of those two extremes impaired Del Bagno’s tolerance to the forces and reduced the effectiveness of his anti-G-straining maneuver, leading to G-LOC.

Computer code can help. The F-16 and some F-35 fighters use software called Auto-GCAS to avert a crash if a pilot loses consciousness. The Air Force says the system has saved eight lives. But the Thunderbirds eschew the technology because its pilots routinely fly at low altitude and in tight formation, and do not want to risk having the software take control of the planes.

Highway to the vomit zone

Military pilots spend years mastering the skills needed to handle the rigors of high-speed flight. I had about four hours of training that included basics like what to do during an ejection. (One tip: “think skinny and pass through” if headed toward power lines.)

Nailing the G-strain is “a little bit like getting the right swing in golf,” says Jan Stepanek, a physician and chair of the Aerospace Medicine Program at the Mayo Clinic in Scottsdale, Arizona. Seasoned aviators like Flack rely on muscle memory to pull it off, know how many Gs they can tolerate before it becomes necessary, and can do it almost subconsciously. I’m not sure I did mine correctly.

Flack had another advantage over me: Since he was in control of the plane, he knew what was coming. Motion sickness in a fighter jet, as in virtual reality and even a car’s rear seat, is caused by the disconnect between what your eyes see, your inner ear feels and how your brain handles that dissonance. Even though I enjoyed a clear view of the sky and terrain below (but not in front of me, as Flack’s seat and other equipment obstructed the view) through the canopy, the stimuli I felt on my inner ear was just too much.

I found being in the plane exhilarating—for a person who loves aviation, it was one of my life’s most intense and overwhelming moments. But the violence of it all added up. Commercial airliners generally bank into a turn at a gentle 25 or 30 degrees, and less when up high. Fighter jets can take a turn at 60 or even 90 degrees. A commercial plane is a bus; a fighter jet is a Formula 1 race car. You feel everything. It’s not subtle.

Flack eased up a bit after I removed my oxygen mask. Eventually he steered the aircraft through a slow barrel roll. “Oh my god, we are upside-down,” I announced, unnecessarily. By that point, I’d had enough.

“If it’s alright, I think I want to head home pretty soon,” I told him.

But Flack had already announced over the radio that we were “RTB,” letting air traffic control know we were returning to the base. A gusting crosswind and shorter runway than he was used to forced Flack to abort our first landing attempt. He retracted the landing gear and brought us around again before nailing the landing in a touchdown he called “pretty challenging.”

I didn’t throw up during the abrupt turns or the knife-edge maneuver or during my dramatic rip-off-the-mask moment. I kept it together during the barrel roll. But I lost it into a Zip-loc bag a few minutes before Flack’s first pass at the runway. I vomited again on the tarmac, while still sitting in the viper trying to get myself together before climbing down the ladder. And, for good measure, I ralphed again in the hangar after chugging a bottle of water too quickly. A doctor handed me two Zofran tablets and I fell asleep on the floor, still wearing my flame-retardant flight suit.

I felt a little better when I woke up, not sure how long I’d been out. But it took a week for me to feel like myself again. Flack has the right stuff. I do not.

Raw footage from my is flight below.

This story was originally published on August 6, 2019.