Joint forces unite for high-altitude training

  • Published
  • By Airman 1st Class Daniel Phelps
  • 20th Fighter Wing Public Affairs
"All right, now go ahead and start counting down from 100 by three's," said Senior Airman Jeylyn Capdevilla, while directing the high-altitude simulation outside the large air chamber.

"100, 19, 97, 94, 87, 77," said a Navy student.

"Alright, go ahead and correct yourself," laughed Airman Capdevilla, an operations and aerospace physiology technician with the 20th Aerospace Medicine Squadron at Shaw Air Force Base, S.C.

The Navy student fastened his oxygen mask to correct himself from his hypoxia symptoms. Hypoxia occours when there is a lack of oxygen in the blood.

"The danger in becoming hypoxic is if it continues, one can pass out and if not corrected, it can become life threatening," said 2nd Lt. Carolyn Price, a 20th AMS operations and aerospace physiologist.

This scenario was part of a class for high-altitude freefall parachutists, covering high-altitude physiology and human-performance related issues.

Thirteen servicemembers from the Army, Navy, Marines and Air Force arrived at the aerospace physiology building here Nov. 2 to take part in the training.

"This class is important for them because the factors that come into play during high-altitude affect your situational-awareness ability and the way your brain works," Lieutenant Price said.

The training was divided into two parts: the classroom session and the high-altitude chamber.

The class goes through the details of the atmosphere, respiration, circulation and what happens to the body at high altitudes, Lieutenant Price explained. It also teaches servicemembers how the body can fail to function in flight at height.

From there, the class studied situational-awareness factors that decrease and specific threats, such as visual illusions.

Once the class session was done, the students headed to the room where the altitude chamber is, had their faces measured and received their oxygen masks.

"The chamber gives the experience of high-altitude effects in a safe environment where people can ensure there are no problems," Lieutenant Price explained.

Once the students were seated in the chamber, Airman Capdevilla helped familiarize them on the equipment.

She took her place at the director's seat after leaving the chamber and gave the students final instructions. She led them in an ear and sinus check to ensure everyone was healthy.

At the end of her instructions, she told them to put on their masks.

The next block of training before the "flight" was as the students donned their oxygen masks so they had time to de-nitrogenize before the flight, Lieutenant Price explained. To eliminate all nitrogen from the blood, the body needs no less than 30 minutes of breathing pure oxygen. This process helps trainees to avoid decompression sickness from the altitude changes.

When the instruction block was completed, the chamber doors were sealed and the cabin's "flight" began.

Once altitude conditions were reached, Airman Capdevilla directed the students to remove their masks inside the chamber.

That was so they could recognize their developing symptoms of hypoxia, she said. After they began experiencing the onslaught of it, they corrected by putting their oxygen mask back on.

"It's really interesting to see what oxygen deprivation does to people," Lieutenant Price said. "I had one student who came in and got real euphoric. He said he felt like he was in the 60s. Their reactions to hypoxia can be really entertaining."

After several minutes of breathing through the oxygen masks to recover from hypoxia, Airman Capdevilla dimmed the lights in the vault and the lights outside the chamber were turned off.

"This is done to simulate night flying missions," she explained.

Senior Airman Marion Franco, a 20th AMS operations and physiology technician and chamber observer, passed out giant cards with Zs and several lines of different colors to the participants.

"These charts that have been passed out are going to be for a visual acuity test," Airman Capdeviila said. "In a minute, you will take off your masks again and see how hypoxia affects your vision."

She then directed the students to remove their masks. It did not take long for the servicemembers to recognize the effects and put their masks back on.

"Everything went reddish," a Soldier said about the effect.

"There was a foggy haze, and then everything became sharp after I put my mask back on," a Marine explained.

A couple of the students experienced what is known as the oxygen paradox.

"After the masks have been taken off, the body begins to compensate for that lack of oxygen," said Capt. Michael Armstrong, a 20th AMS operation and aerospace physiologist. "When the mask is put back on again, a rush of oxygen comes back to the body. This can cause a shock to the system and a brief worsening of hypoxia symptoms before they get better."

This section concluded the final portion of their training. Once all the students donned their oxygen masks, the lights came back on and the chamber "descended back to regular elevation."

"The chamber gives the students experience going to altitude, pressure breathing and gas volume changes," Lieutenant Price said. "In the chamber, you have to stay ahead of hypoxia symptoms more than in an actual aircraft. It's important the participants learn how fast they can become hypoxic, because otherwise they wouldn't realize how significant it can be and how fast it can happen."

Navy Senior Chief Petty Officer Mark Wyland, with the Mobile Unit 2 detachment Crane explosive ordinance disposal, from Naval Support Activity Crane, Ind., was taking the course again.

"Every five years or so, people will come back to take the course as a refresher," Lieutenant Price said. "Life and lifestyle changes can affect the hypoxia symptoms people will experience. The refresher course also allows them to put the dangers of hypoxia back to the forefront of their minds."

Petty Officer Wyland said he experienced numbness and his mental acuity degraded in the chamber.

"It comes on pretty quick," he said. "It's important to be able to identify those symptoms so you can take the appropriate actions to keep yourself and your coworkers safe."