SHEPPARD AIR FORCE BASE, Texas (AFNS) -- One of the secrets behind nearly 75 years of U.S. air dominance is the quality of its pilot training. But long before students learn to identify, out-maneuver and defeat enemy aircraft, they have to learn to deal with a much more subtle but no less dangerous threat: hypoxia.

Essentially a lack of oxygen in the brain and blood, hypoxia first became a factor in military aviation during World War I as better aircraft enabled pilots to reach higher altitudes where there is less oxygen - an environment the human body is not designed for.

"Pilots are basically normal people in a very abnormal, dynamic environment," said Capt. Matthew Ramage, who is assigned to the 82nd Aerospace Medicine Squadron. "Our job in flight medicine is to make sure pilots are both physically fit and mentally prepared to deal with the unique stressors placed on their bodies in an aerospace environment, including oxygen deprivation."

Once pilot trainees meet the rigorous battery of medical testing prior to starting Undergraduate Pilot Training, they begin physiological training, where they learn about cabin pressurization and oxygen systems. In all, students get 50 hours of physiological instruction in their first year of pilot training.

The training includes classroom time as well as hands-on time with equipment. But the heart of the program is the altitude chamber, where students get a personal experience with oxygen deprivation as well as a chance to observe how it affects their peers.

Given the high-performance qualities of modern aircraft, pilots may have only seconds to take corrective actions once the signs of hypoxia are evident. Complicating this is the fact that often, hypoxia initially creates a sense of euphoria.

Ensuring pilots and aircrew can recognize hypoxia and take corrective actions as needed is the very essence of the training, said 1st Lt. Ezekiel Duran, an aerospace and operational physiologist with the 7th Aerospace Medicine Squadron at Dyess Air Force Base, Texas.

"What we're teaching them to look for are both subjective and objective signs of hypoxia," Duran said. "Subjective signs include how they're feeling, things like air hunger or hot and cold flashes. Objective signs include things like cyanosis, when fingernails, lips or skin turns blue. We help students recognize these signs and teach them how to correct the situation."

That's why hypoxia training requires pilots to complete specific actions under reduced oxygen conditions, including locating and activating oxygen equipment, turning on the regulator, checking connections, ensuring the safety of fellow aircrew members, descending below 10,000 feet and landing safely.

Other types of physiological training include parachute familiarization, ejection seat operations, local area survival and a wide array of instruction on communication and self-preservation skills.
The physiological training process does not stop at initial training. Pilots and other aircrew members are required to attend physiological refresher training every five years, which includes hypoxia recognition training.

Refresher training for hypoxia can be accomplished through use of an altitude chamber or the Reduced Oxygen Breathing Device. The ROBD can be used in several different types of flight simulators including the Hypoxia Familiarization Trainer. The HFT uses airframe-specific software to integrate flight operations with hypoxia in a simulator environment.

Currently, only combat aircrew flying in ejection seat aircraft are authorized to complete refresher training using the ROBD; however, Air Force policy will soon provide that same option to other communities once the weapon-system specific training procedures are approved and appropriate training devices are in place.

"Since the introduction of ROBD, it has enhanced training for aircrew by enabling them to recognize the subtle signs of hypoxia, whether cognitively or subjectively," Duran said. "As we know hypoxia is subtle and insidious. Now (pilots) can operate in an environment they are familiar with and can experience hypoxia symptoms on a more realistic and operational level."

At Sheppard AFB, everyone entering undergraduate flight training is required to visit the 82nd AMDS. As the home of the Euro-NATO Joint Jet Pilot Training program, the base hosts 13 different NATO partners, training approximately 200 pilots annually.

For Maj. Eydin Hansen, the 82nd AMDS aerospace and operational physiology flight commander, ensuring Airmen are trained to maximize human performance and combat human factors that can derail them and their aircraft in flight is the bottom line.

"Completing a flight physical, altitude chamber and centrifuge training, not to mention all the academic hours needed for high performance flight, is the just the first step," Hansen said. "The next step is operating safely in a dynamic flight environment, let alone under duress. In our business you may only get one chance to get it right, so their decisions have to be accurate and second nature."

Photo: Tech. Sgt. Jennifer Flecker performs shut-down protocol on a Reduced Oxygen Breathing Device at Dyess Air Force Base, Texas, on June 6, 2012. The ROBD is used during hypoxia refresher training to induce the actual symptoms of oxygen deprivation in aircrew members at higher altitudes. Flecker is the 7th Aerospace Medicine Squadron NCO in charge of Aerospace Operational Physiology,(U.S. Air Force photo/Dan Hawkins)