I was anxious for the altitude chamber; I think all of us in the class were. In the first half of the day we learned about high-altitude physiology and had an excellent demonstration on spatial disorientation. In fact, we spent quite a bit of time in a few sensory deprivations, partial-motion simulators to drive home the point of trusting your instruments in IFR conditions. The sims don’t fly well and the controls are a little difficult to manipulate, but that’s the point. Sitting in a darkened simulator, with only a small red light and a little illumination from the instruments, we were tasked to fly the airplane on a course given by a simulated ATC. Then the instructors had us move our head, look around, perform a couple of tasks, and do it quickly. This action was to force the fluid in our ears to move, making the body feel as if it was moving. Then back to flying, on instruments.
Forget what you feel, because your body is wrong. Your body will feel as if you are turning or tumbling. I could have sworn I was making a hard left turn. Then the instructors quickly open the door, and you discover you are actually stationary. Your eyes and body now agree that, of course you are not moving, and, yes, your instruments were right. This was a fantastic opportunity to experience real spatial disorientation in a safe, well-controlled environment. When I took this course, I was recently off an instrument checkride and my instructor had me practice head movements as to not confuse my body, but in this setting the instructors were to able make my body feel out of control, all while proving that using only your instruments will keep you in control.
Then comes the afternoon, the moment we all were waiting for. We walked into the altitude chamber, took our assigned seats, and practiced using our masks. After a few minutes of orientation, we turned around and watched as the instructors slowly sealed the door. It sounded like a bank vault was closing, and we were on the inside. Next came a hissing sound as the instructors did a few last-minute pressurization checks. A quick run up to a few thousand feet followed by a decent to ground level ensured everyone’s sinuses were ready for the ride. Once everyone indicated a go, we quickly climbed and experienced a simulated rapid decompression equating to a flight level of 25,000 feet. The decompression was exciting as the chamber briefly filled with a fog. We secured our masks and checked our pulse oximeters to ensure our oxygen levels had stabilized, and then we prepared for the real fun.
At instruction, we removed our masks and breathed normally. I didn’t feel any shortness of breath, just felt like I needed to breathe a little faster to get air. After a minute or two, we were asked to do some routine paperwork exercises. I elected for a couple of mazes and a few math problems. Simple, I thought, too simple (more on that later). The maze took just seconds, but the math took little longer. Another two, three, then four minutes pasted. I had a headache, similar to not having eaten all day, but still no euphoric symptoms that I had read so often about. Most of the class had already refastened their masks, however my oxygen levels were still okay, so I continued.
After about five and a-half minutes, my oxygen level remained in the low 60s; I still had a headache, but was frustrated with the experience because I thought I would have felt more of an effect from the high altitude. There were participants who needed the instructors to intervene with putting on masks and forcing oxygen, but I didn’t have any issues. Sure, I had a headache and I was a little tired, but no real negative effects – or so I thought.
It took about 10 seconds for the oxygen from my mask to hit my blood stream. And wow, it was reminiscent of the ALS ice-bucket challenge--becoming immediately refreshed, completely aware, and awake. I looked down at my “easy” maze, and it was a mess; my lines ran through maze walls that I didn’t see when off the oxygen mask. Then I glanced at my math; better than the maze, but my fifth grade teacher would have marked me down a few points.
After we exited the chamber and reentered the classroom, we all shared our hypoxia symptoms with the class. Many participants were surprised to hear what symptoms others observed in them, including symptoms participants weren’t aware occurred! And the timing varied as much as the actual symptoms themselves. Some instantly succumbed to the high altitude; others were reasonably fine for several minutes. I was expecting and waiting for the fun euphoria symptom; it never came. So without this training, I likely wouldn’t have recognized what my individual hypoxic symptoms are, at least not as quickly.
When flying an aircraft, moments matter, so I recommend you consider spending a day to learn your specific hypoxia symptoms and how to recognize them. Even if not at flight levels, having oxygen at certain altitudes, while flying at night will make a world of difference. Flying at night with oxygen was also demonstrated while in the chamber.
Watch for Part 2 of Jim’s experience in this life-saving survival course. In the meantime, if you need expert advice or help finding the right coverage to fit your insurance needs, please contact AOPA Insurance (aopainsurance.org) or call 800.622.(AOPA) 2672.