Navy aviators and aircrews have been undergoing hypoxia training since World War II, but a new system tested at Aviation Survival Training Center (ASTC) Jacksonville promises to make that training safer, more efficient and more realistic.

The first manned tests of the 9A19 Normobaric Hypoxia Trainer (NHT) took place with personnel from Patrol Squadron (VP) 30 at ASTC July 25.

NHT simulates altitude change by altering the composition of the air the test subjects are breathing. Oxygen is pumped out of the closed testing chamber and is replaced by nitrogen. The more the oxygen level is reduced, the higher the altitude is simulated. NHT can simulate an altitude as high as 25,000 feet.

“The idea is to provide hypoxia training at normal atmospheric conditions,” said Rocco Portoghese, senior research and development engineer for the Rapid Design and Fabrication Lab of Naval Air Warfare Center Training System Division (NAWCTSD) in Orlando where the NHT was developed.

“It’s an inherently safer method of hypoxia training” when compared with hypoxia training in a low pressure chamber.

Hypoxia is a potentially deadly condition where there is a deficiency in the amount of oxygen reaching the tissues in the body. Prolonged lack of oxygen can result in light-headedness, confusion and eventually loss of consciousness. 

Navy pilots and aircrews undergo hypoxia training every four years so they can recognize the onset of the symptoms and take proper steps, such as donning their oxygen mask and following their emergency procedures.

Earlier hypoxia training consisted of putting the aircrews into hypobaric chambers, where the pressure inside was lowered to mimic flying at high altitudes.

The pressure change was risky as it could result in ear and sinus damage, as well as decompression sickness. This type of training also restricted pilots from flying for at least 24 hours.

A later training device called the Reduced Oxygen Breathing Device (ROBD) was safer because there was no change in pressure.

However, the pilot or aircrew had to wear a mask for the training. This made it unrealistic for aircrew members who do not generally wear an oxygen mask while flying, such as P-8 pilots.

“We needed to find a way to get them to experience hypoxia without wearing a mask,” said Lt. Cmdr. Phillip Dobbs, ASTC director.

“This new hypoxia trainer is going to allow people to come into a hypoxic environment, fly a simulator, or if they are a non-flying aircrew, they will perform aircrew equivalent tasks without their masks on, like they normally would.”

NHT contains flight simulators for as many as four pilots and workstations for up to six non-pilot aircrew. 

“Their heart rate and blood oxygen saturation levels are recorded in real time,” Dobbs said.

“They are able to communicate with their instructor, who is outside the chamber. Safety observers inside help them and provide assistance if needed.”

Four cameras are also in the chamber sending a live feed to a monitoring station. 

“When we want to get the air back to normal, we switch the computer to give them more oxygen,” Dobbs said.

“In a worst-case scenario, we just open the doors and they walk outside and breathe normal air. There are so few safety hazards with this trainer; that is what makes it an elite training device.”

The first test was a maximum capacity test with 10 students and two safety observers in the chamber. The second test was a minimum capacity test with one student and one observer. Each test took about 30 minutes to complete.

Cmdr. J.T. Morarend, a physiologist with Naval Aerospace Medical Institute at Pensacola, participated in both tests.

“I have done this type of training several times in my career, and this was a lot more realistic,” he said, “and a lot more comfortable.”

There is also no down time for pilots, as they are able to fly immediately after the training. Personnel from NAWCTSD, who developed NHT, witnessed the tests.

“The tests went outstanding,” said Lt. Cmdr. Marcus Gobrecht, integrated product team leader who helped to deliver and install the NHT.

“We met all of the metrics of our specifications.”

The NHT took two months to install at ASTC and was about two years in development.

“Once it proves its capability, they will build seven more for the other survival training units,” Dobbs said.

“They are supposed to be all online by September of next year.”

Capt. B.L. Bohrer, of Naval Air Systems Command, which takes care of acquisitions for all airborne training systems for the Navy and the Marine Corps, also witnessed the tests.

“This is a monumental event,” he said. “It is groundbreaking. No one else in the service branches are doing this.”

ASTC is a division of the Naval Survival Training Institute (NSTI). NSTI and NAMI are detachments of Navy Medicine Operational Training Center (NMOTC), whose mission is to provide operational medical and aviation survival training.

NMOTC is part of the network of Navy medicine professionals who support Sailors and Marines worldwide, providing critical mission support aboard ships, in the air, under the sea, and on the battlefield.