What Is G-LOC
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What Is G-LOC And How Does It Work?
Here at Sky Combat Ace, we regularly knock the socks off of anyone who comes through our doors seeking the ultimate adventure. One experience some people have started to request after seeing videos of our customers is "G-LOC," a.k.a. Gravity-Induced Loss of Consciousness.
In Laymen's terms, losing consciousness when our planes pull more G's than your body can handle. Most of the time, a customer knocks themselves out from pulling back too hard on the controls trying to recreate a maneuver we show them.
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That got us thinking, we perform these crazy acrobatic stunts at up to 250 mph, sometimes 14 times a day. As a former F-16 fighter pilot myself, I'm able to pull up to 12 G's safely and unaffected. But what EXACTLY happens to those of you who request to pass out and sometimes take that little 7-second nap after only pulling as little as 5 G's?
Here's the research to help you better understand the coveted G-LOC, which will come as good news to all you would-be adrenaline junkies who are daring enough to request it. It turns out that G-LOC is safer than most think, and you're likely to lose more brain cells knocking back a few too many at the local casino in Las Vegas than knocking yourselves out in our Extra 330's.
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Flight and Newton’s Laws of Motion
Ready for a bit of science and classical mechanics? As Sir Isaac Newton laws of motion and universal gravitation theories explain, the gravitational field we live in on earth exerts a constant 1G force on our bodies. Here are the basics of Newton’s laws¹ you should understand:
- If an object is at rest or in a state of motion, it will remain at rest or not change its motion unless external forces act on it.
- The force on an object is equal to its mass times its acceleration.
- When two objects interact, they apply forces to one another that are equal in magnitude and opposite in direction.
How Gravity Changes During Flight
As Newton’s law states, in flight, the acceleration due to jet engines or free fall acceleration due to gravity on our unit mass (or weight) changes the amount of gravitational pull we or any falling object experiences (without considering air resistance).
This gravitational pull is expressed in G's. So 3G's equals three times² the earth's gravitational pull. In other words, if you weigh 150 lbs at 1G, you will weigh 450 lbs at 3G. In SI unit of mass, that’s about 68 kg at 1G and 204 kg at 3G!
Of all the systems in our body, the circulatory system and blood vessels are most affected by flight. Under normal circumstances, our bodies do a pretty good job regulating the blood flow to the brain. But the extra pressure from increased G's can pull blood away from our brain and down to our feet, sometimes causing G-LOC.
What Is G-LOC?
Loss of consciousness due to the acceleration of gravity on the body is better known as G-LOC. It occurs when increased force due to gravity is applied to the body, causing a loss of consciousness. Most people can withstand anywhere between 2 to 5 G-forces relatively unaffected.
After high intensity or longer duration, a few things can happen before a G-LOC. This is why we instruct you in the safety briefing to tell us when you're experiencing any or all of these symptoms so we can ease off the throttle:
- Tunnel Vision - loss of peripheral vision
- Greyout - Loss of color vision
- Blackout - Loss of sight, but still conscious
How Does G-LOC Work?
A healthy person may get G-LOC around 5-6 Gs, and others can withstand up to 9 Gs. When extreme positive G-force is applied (Tail slides, Hammerheads, and our favorite, the Lomcevak), external forces of gravity divert blood flow to the brain down to the feet. This is why we flip you knuckleheads upside down to get that blood going back towards your noggins.
How Do Pilots Not Pass Out From High G-Force?
In addition to extensive training and medical advice, some pilots use two resources to prevent them from passing out while flying³.
1. G-suit.
This tight-fitting garment applies pressure to the pilot's legs and abdomen using air pressure (like getting your blood pressure). It is attached to the actual jet, measures the amount of Gs the pilot feels, and then automatically applies the appropriate pressure to prevent them from passing out.
2. Anti-G Straining Maneuver (AGSM).
The pilot will tighten and release muscles in the glutes, legs, and abdomen to keep blood flow constant.
Together, these measures prevent too much blood from settling in the legs, so extra Gs can be pulled by professional pilots.
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Do Fighter Jets Have Autopilot if the Pilot Gets G-Loc?
Fighter jets are equipped with an automatic recovery system called Auto-GCAS⁴ (Automatic Ground Collision Avoidance System). This system determines if a collision is probable based on trajectory and speed. If so, it first warns the pilot, and if the pilot doesn't respond, the system can automatically pull a jet out of a nosedive.
Can G-Loc Be Dangerous?
No one has ever died from a G-LOC (except maybe die from embarrassment from their video). After proper oxygenation (again, the part where we wake you up from your quick slumber by inverting the plane), the only symptoms that may persist are a little fatigue.
Recovery is prompt following the removal of the G-force. A period of disorientation can occur, and vivid dreams have been reported during unconsciousness. We once had a member of the Canadian Tenors who came out to fly with us say he was happy he experienced G-LOC because he was back at home having Christmas dinner with his family, who he hadn't seen in months!
No matter your style, it's always an adventure here at Sky Combat Ace. If you'd like to see how many Gs you can handle, check out our flight experiences and book your flight today!
Sources:
¹Britannica, The Editors of Encyclopaedia. (23 July 2021). Newton's laws of motion. Encyclopedia Britannica. Retrieved 19 January 2022.
²Jedick, R. (5 April 2013). Pulling G’s – The Effects of G-Forces on the Human Body. Go Flight Med. Retrieved 19 January 2022.
³Verger, R. (3 January 2020). A pilot passed out while flying an F-15 over Oregon. Here’s what happened next. Popular Science. Retrieved 19 January 2022.
⁴Dockrill, P. (14 September 2014). WATCH: F-16 Autopilot System Saves The Life of an Unconscious Fighter Pilot. Science Alert. Retrieved 19 January 2022.
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