Thirty-six years after the release of the first work of top Gun, Tom Cruise never stops making us dream. For Top Gun: Maverick (directed by Joseph Kosinski), the actor once again stepped into the shoes of fighter pilot Pete Mitchell. He hoped to fly a real F-18 fighter jet, but the US military refused to give him the controls. Question of budget, safety and health: To take advantage of the Gs, the body of elite pilots, considered true top-level athletes, is put to the test. This is how Stéphane Perrey, a researcher at the University of Montpellier, recalls it in an article published on the site The conversation (source 1).
“Our species is acclimated to a world of constant gravity, in this case, a pervasive acceleration force born of Earth’s pull. However, there are circumstances in which our bodies are subject to greater than classical Earth gravity. .. This is again a matter of acceleration”, indicates the expert in the explanatory statement. In aeronautics and automotive, we refer to the G (for Gravitational), as a unit of acceleration. “And its effects can be terrible.“, he warns.
What are the health consequences for pilots?
Flight is about overcoming gravity to rise through the air, and speed is of the essence, explains Stéphane Perrey.
Any aeronautical maneuver can, therefore, expose our body to significant accelerations, with significant repercussions at the cardiovascular, cerebral and joint levels.
Therefore, some aircraft are capable of reaching 12G, with acceleration climb rates in excess of 15G/s. Figures that speak little in absolute terms, which the researcher then dissects:
- While lying motionless on the ground, the acceleration felt is 1G. “Everything is going well”.
- In 2G, for example, when making a banked turn of 60 degrees, we already have a moderate compression sensation in our seat, a difficulty in moving”.
- Beyond 3G, self-regulation mechanisms are overcome, with the immediate consequence decreased vision and mental performance. For cause? As soon as a driver accelerates, the G-force forces the heart to work harder to bring blood up to the level of the brain. If it fails, it will cut off the oxygen supply to the brain, but also hearing and sight.
- From 8-9G, “it is impossible to mobilize their extremities, except for the extremities“. Note that accelerating too quickly can also cause a loss of consciousness.
And Stéphane Perrey to specify that there are three main types of G: “We can suffer side G (Gy) during a curve resulting from centrifugal acceleration pushing us outwards. For horizontal acceleration or deceleration, we are talking about Gx. Finally, Gz occurs during an aircraft descent or after a sudden ascent.”
We are more particularly sensitive to these accelerations suffered in the vertical axis (Gz), that is to say from the head to the feet, since it is there that we feel the force of gravity of the earth necessary to maintain its balance.
Fighter Pilot: Unbreakable Physical Condition
To withstand all these parameters, fighter pilots undergo a strict training program, which includes endurance and strength exercisesthat increase their tolerance to the effects of G. “Any aerobic endurance activity (even in apnea or at altitude) is good for the cardiovascular system,” recalls Stéphane Perrey.
They also focus on core strengthening exercises (lining, push-ups, pull-ups, sit-ups, etc.) and neck muscles. “High G’s make the head heavier than normal, and with a helmet on, that’s a lot of weight to bear. Pilots of the fastest, most agile aircraft have to constantly watch their external reference points and change head position.” head during its maneuvers.”, indicates the expert.
Note: To measure the G to which they are subjected, aircraft pilots are equipped withthree-axis accelerometers (lateral, vertical and horizontal): so they can know in real time what they are going through and adapt their driving. Various tools also allow them to counter G’s harmful effects, such as anti-G belts or pantsconnected to the plane, which automatically squeezes and thus restricts blood circulation in the lower part of the body.