Aerospace Physiology: Training the early warning system Published Oct. 25, 2021 By Tech. Sgt. Isaac D. Garden 20th Fighter Wing Public Affairs SHAW AIR FORCE BASE, S.C. -- The human body is a marvel that has the ability to deliver feedback, which acts as an early warning system to change our current situation for better or worse. The body operates best at sea level with all senses firing in proper orientation, but as altitude increases, feedback starts rolling in. The 20th Operations Support Squadron aerospace physiology specialists have capitalized on the body’s early warning system, and have used it to further train pilots and aircrew. “Aerospace Physiology is responsible for teaching pilots and aircrew the essential skills for in-flight emergencies and to combat the onset of G-forces in the F-16,” said 1st Lt. Zachary Carson, 20th OSS chief of aerospace physiology. “These skills include recognition and correction for hypoxia, decompression sickness and preparation for G-tolerance.” In the dynamic environment of flight, recognizing the symptoms of altitude hypoxia could mean the difference between returning to base or loss of life. The onset of hypoxia is largely dependent on altitude, climb rate and duration. On average, a pilot in an unpressurized environment at 25,000 feet will have three to five minutes before exceeding their time of useful consciousness. “The onset of altitude hypoxia is slow and insidious, which is why it is so important for pilots and aircrew to recognize their symptoms,” said Carson. “Our Airmen can practice recognition and correction for hypoxia in a safe environment (correction involves manipulating the oxygen regulator to provide 100% oxygen). If symptoms are not recognized, the depletion of oxygen to the brain will eventually lead to unconsciousness and death.” The F-16 Viper is a fighter jet that can fly at speeds greater than Mach 2; twice the speed of sound. The term “pulling Gs,” also known as the G-force, refers to the force of gravity weighing down on the body. The F-16 is capable of pulling nine Gs, which makes your body feel nine times heavier than usual. “Over time, your body gets used to G-forces,” said Capt. Marie Carillo, 79th Fighter Squadron assistant director of operations, F-16 flight lead. “You continue to pull Gs and your vestibular system gets used to the effects of flight. At this point, we fly so often that AGSM (Anti-G Straining Maneuver) is instinctive. We’re executing AGSM up to 19 times per sortie. I don’t even think about it anymore; once you feel the G-onset, you start your AGSM.” The AGSM teaches pilots to tense-up the lower body, apply a 3-second respiratory component and relax the upper body. This allows pilots to force blood back to the brain and prevent G-induced loss of consciousness. The training that Airmen receive ensures combat readiness and sharpens the tactical proficiency needed to maintain a prepared force, keeping Airmen safe and in the fight. “On a daily basis, we’re in an environment where we need to recognize signs and symptoms of spatial disorientation and hypoxia, said Carillo. “Previously, I became disconnected from oxygen at 18,000 ft., and this training helped me recognize those signs and symptoms and reconnect to oxygen quickly.” Hypoxia symptoms include tingling in the extremities, lightheadedness, numbness, hot/cold flashes, labored breathing, headaches and blurred vision. If you have ever been hiking, biking or skiing at high altitudes and felt lightheaded or short of breath, you have experienced mild hypoxia. Airmen receive advanced, realistic and innovative training opportunities to hone individual skills and integrate capabilities that prepare Airmen for the most extreme circumstances before they ever set foot on a plane. “All pilots and aircrew accomplish aerospace physiology training during their initial training pipeline, and this must be done via hypobaric (altitude) chamber,” said Carson. “The training supports proper pre-flight and post-flight preparation in anticipation of high altitude and highly dynamic environments to ensure the health and safety of our Airmen, and to keep them flying.” By preparing for a worst case scenario in-flight, 20th FW pilots and aircrew ensure we can respond on a moment’s notice to defend U.S. interests and protect U.S., allied and partner forces.