The first step in my transformation from "pilot" to "fighter pilot" took place on 27 July 1999, the Tuesday directly following my graduation from USAF Undergraduate Pilot Training. It was a trip back to the Centrifuge (colloquially called "the ‘fuge") at Holloman AFB, NM.

The fighter aircraft in the Air Force today are capable of extremely high G-loading -- much more, in fact, than the pilots can sustain. A pilot's average "resting" G-tolerance is between 4 and 5 G, while a fighter jet can sustain anywhere up to 9Gs or more. In order to bridge the gap, pilots need special equipment and physical training to boost blood pressure to the head and prevent G-induced loss of consciousness, known as "G-LOC". The anti-G suit only provides approximately one extra G of tolerance, so a pilot's most significant weapon in the war against G-LOC is the Anti-G Straining Maneuver (AGSM). The AGSM is a method of tensing your leg and lower torso muscles and rhythmically breathing to increase blood pressure. A good AGSM can add nearly 2.5Gs to a pilot's tolerance against the incapacitating effects of Gs.

Part of the Air Force’s G-force resistance training regime is two trips to spin in the centrifuge. Basically the centrifuge is a gondola outfitted like an aircraft cockpit on the end of a long arm. A 6500 ft-lb. engine spins the arm and the gondola rotates outside the circle; the transverse inertial force exerted on the pilot is the same as would be experienced in the cockpit of an aircraft in a high-G turn. Inside the "cockpit" is a control stick and a simulated Heads Up Display (HUD) from a fighter. There is also a camera inside so the physiologists can watch us as we experience the G-loads. The camera feed is taped by the physiologists for use as a debriefing tool after you spin so you can see your mistakes and be aware of what you need to correct. The fuge operators allow us to videotape the camera feed for ourselves, which makes a nice keepsake for a pretty unpleasant experience.

This second trip was to be vastly different from my first visit 6 months earlier. On my initial visit to the centrifuge before starting T-38 training, there had been no performance requirement – it was merely an introduction to the high-G environment. A G-LOC during any of those spins simply meant you’d have to try it again – and you’d go home with a souvenir videotape of yourself looking completely ridiculous as you blacked out. On this trip, there were much higher stakes at risk: if we didn’t pass, our fighter pilot careers (as fledgling as they may have been) would have been over.

In order to continue on to fly our assigned fighter aircraft we would have to pass a qualification spin by sustaining a required G-force for a specified duration. We would also have to demonstrate to the physiologists that we could properly perform the AGSM. The requirement for F-15E-bound pilots was 7.5G for 15 seconds. In all honesty, I wasn’t too worried about my qualification – I had performed the same 7.5 for 15 spin 6 months earlier with no problem. In addition, I had grown much more accustomed to the high-G environment through 6 months of flying the T-38 Talon in SUPT. I was confident that these two factors would translate into success for me this time around.

I flew to El Paso, Texas with two of my SUPT classmates. There, we rented a van and drove just over an hour north to Alamogordo, New Mexico, the location of Holloman AFB.. Holloman is in the high desert of the southwest: barren desert flatlands. The base is near the White Sands missile range, where America's space program was born by testing captured German V-2 rockets in the 40s and 50s.

The next morning after arriving at Holloman, we showed up to the Physiological Training building. First, we had about two hours of academic training about the physiological effects of the high-G environment, as well as more training about how to perform the AGSM. After demonstrating our styles in front of the class (for maximum embarrassment and to ensure we’re doing it right), it was time to move next door and spin in the 'fuge!

I was to be the third man to spin. Watching my buddies spin before me made me aware that this was not going to be a pleasant experience. While at high G, their faces were distorted and they looked most uncomfortable while straining. The fact that they nearly couldn't walk after the ride made the anticipation even more! I strapped on my G-suit and stepped into the fuge. One of the toughest parts for me was when the fuge started to spin because I got a bit spatially disoriented. The computer monitor HUD in front of you displays a simulated horizon showing a right turn, and if you can keep looking at that you'll easily re-orient your gyros.

The total centrifuge qualification profile consists of 5 spins. The first spin is designed to find your resting G tolerance with no AGSM or G-suit. The first spin also tests the actual strength of your AGSM technique. Here’s how it works: you start out at 1.2G, then 0.1G is added every second until you reach the maximum target G of 8.0G¹. At the beginning, the pilot is not supposed to strain. As the G is increased, the pilot begins to strain when there is noticeable vision loss. For me this occurred at 4.4G. From then on, you had to execute a proper AGSM technique to maintain vision all the way up to 8G. The difficult aspect of this profile (aside from going to 8G with no G-suit!) is that. at 0.1G per second, you’re performing an AGSM for about 30 to 40 seconds. That half-minute can seem like an eternity when your skull weighs 100 lbs. and your body nearly half a ton!

As the Gs were piling up and I continued my AGSM, I noted again that the G-forces experienced in the ‘fuge seem much worse than the same G-force experienced while actually flying. It defies physics, I know, but I’ve talked to many others who feel the same way. On this first spin, I was trying out a different technique – I was not looking at the G-meter and clock, but instead focusing completely on the lightbar that is used to measure vision loss. It seemed like the spins had lasted longer on my previous ‘fuge visit -- I had been watching the individual seconds click off (temporal distortion?) and seeing the G increase. Even with this technique, I started to doubt if I was going to make it as the G continued to build. The operators were counting off the seconds for me and instructing, "one...two...three...BREATHE!" While this was helpful, I was already starting to experience those same feelings of air hunger that I’d had on my previous trip. I felt like I was suffocating. I decided that I was committed to sticking with it (I could terminate at any time simply by releasing the stick) until I either G-LOCd or the ride was over. This determination worked to my benefit, as it turned out. Soon I started to get some light loss and, believing that I was somewhere around 6G and still had a ways to go, I gave my AGSM my last bit of effort and really tightened down. Soon that last effort was spent – I was getting very tired and the suffocation feeling was almost unbearable. Finally I started to gray out and desperately hoped I was somewhere near 7.3G. I had just started to release the stick when I heard the fuge operator call "Terminate," indicating I’d made it all the way to 8G and the ride was over!

The second spin was designed to warm up your AGSM endurance and allowed us to use the G-suit. This was a rapid G-onset (6 G/sec.) up to 1G over my resting tolerance (5.4G) and lasting 30 seconds. This time I methodically tensed up my leg and skeletal muscles and concentrated on making my chest pressure high and air exchanges crisp. Once I was "on top" of the Gs, the operator advised me to let off on my strain. Previously, I’d been giving my AGSM my all-out effort, and often I’d give too much strain for the G I was experiencing. So, I backed off on the intensity and strained as needed. I discovered I was fine with only minimal chest pressure and rhythmic breathing, but fully using the lower body muscle tensing. I found the 30 seconds passed rather quickly and easily.

The third spin was the much-anticipated qualification spin. For me that meant 7.5G for 15 seconds. Since this was "the big one," I gave it my maximum effort the whole way through. Watching myself on the videotape later I saw the most intense look on my face I’d ever seen! In very short order, the spin was done and I passed with ease. I cheered out loud to the operators – my first hurdle on the way to flying the Eagle was complete! But, there were still two more spins to go and I was already starting to feel fatigued from the first 3 spins.

The easiest spin of the day was the "check six" – 6G for 10 seconds while looking over your right shoulder as if checking your jet’s six o’clock position. The challenge on this one was that the operators were no longer counting off the seconds for the rhythmic breathing. Now it was up to us to demonstrate our technique to them for evaluation. This spin, too, seemed to go by in no time, and now I only had one more to go.

The final spin in the centrifuge is the real kicker. The physiologists and operators of the centrifuge like to call it "the price you have to pay for the joys of flying a fighter!" This is the ACM – Air Combat Maneuvering – spin that simulates a dogfight. It’s a no-help-from-the-operators, no-holds-barred test of your G-straining ability. To simulate a dogfight, the gondola has a simulated HUD on a TV screen. In the HUD you see tail view a computer generated F-14 flying around with a horizon and landscape. You simply have to pull the stick back, put the F-14 in the HUD crosshairs, and gun his ass with 20mm! At least the designer of this profile had the good sense to allow AF fighter pilots the joy of gunning a "Tomgrape" – it’s just too bad the rest of it sucks! The total profile lasts about a minute and you spike up to a maximum of 8 or 9G in four "engagements." Between fights there are 3-4G "resting" periods (who ever heard of "resting" at 4G?). At first, this profile was fun, but after the second 8G "fight," I was getting very tired and it seemed like this was lasting an eternity. You’ll recall that on the 5.4G spin I’d relied almost completely on my leg muscles to fight the G. By now those over strained muscle groups just didn’t have the endurance to make it through the whole fight. By the time the Tomcat "turned and burned" his way up to 8G for the last time (who the hell has ever heard of a F-14 pulling 8G anyway?) I didn’t have it in me to follow him. I made it up to 6.7G before letting go of the stick and calling it quits, exhausted. I never G-LOCd, but I was so fatigued that I realized if I’d continued I would have! Fortunately since I’d satisfactorily performed over most of the spin, they let me pass.

Once the fuge stopped spinning, one of the operators came and opened the door of the gondola to let me out. I was so spent that I couldn’t get myself out of the seat and had to be assisted. I flopped down on the chair that awaits close by for such an occasion. As I fought back the urge to puke, my classmates cheered and high-5’d me.

I’d made it!

I was going to the Strike Eagle!

Capt Randy Haskin is an F-15E Strike Eagle pilot at Seymour Johnson AFB, NC. He is a graduate of USAF pilot training at Columbus AFB, Mississippi. You can read about his experiences as a student military pilot at his website called "The Road To Wings."