Physiological Training Notes

I completed the FAA Aerospace Physiology Training at Peterson AFB in Colorado Springs. The training was arranged through the FAA Civil Aerospace Medical Institute (CAMI), using Peterson Air Force instructors and facilities. It was a training course to familiarize US civil aviation pilots and flight crews with the physiological and psychological stresses of high altitude flight. The course consisted of class instruction and time in an pressure chamber up to 25,000 feet simulated altitude. The course covered.

click photos to enlarge

  • Physics of the Atmosphere

  • Respiration and Circulation

  • Decompression

  • Stress

  • Hypoxia

  • Hyperventilation

  • Decompression Sickness

  • Pressure Equalization Difficulties

  • General Aviation Oxygen Equipment

  • Altitude Chamber Oxygen Equipment Familiarization

  • Altitude Chamber Flight Profile & Flight

  • Spatial Disorientation

Pressure chamber, Peterson AFB

The attached files are:

  • class handouts

  • FAA AC-61-107A, pertaining to the operation of aircraft above 25,000 feet

  • USPA high altitude manual

Spatial Disorientation chair

Links to websites:

My course comments:

  • The 10 participants were all civilian, consisting of flight instructors, test pilots, a gilder pilot (wave soaring) and myself (parachuting & paragliding). Instructors were military, 3 were physiological trainers, 1 was in charge of chamber operations. 3 staff were in the chamber on continuous oxygen and technicians and medical staff were outside. Masks were pre-fit to the participants and attached to intercom equipped helmets. I used an older model mask which was comfortable and provided a tight (necessary) seal, but it had limited access to the nose area needed for Valsalva technique ear pressure equalization.

  • The class discussed spatial disorientation, including case studies. Spatial awareness is strongest visually, then inner ear. Disorientation is most often at night or near dark.

  • Time of useful consciousness (TUC) at 25,000 is 3 minutes as per the Air Force.

  • Inner ear pressure equalization technique used was Valsalva, but there are other techniques (see link at bottom of page).

Training certificate

The Pressure chamber experience was :

  • 30 minutes pre-breathing 100% oxygen to reduce nitrogen by 30%,

  • then to 18,000 on 100% oxygen. At 18,000 oxygen masks were removed for 10 minutes. The 18,000 stay was mostly to identify any participants with symptoms or problems at altitude. The first noticeable event was during the ride to 18,000 when the air in the chamber shed it's moisture in a fog and the temperature correspondingly dropped. We trained how to attach and use a portable 'walk around' oxygen supply, and reattach ourselves to the airframe O2 console. We experienced 'forced/emergency' oxygen flow,

  • and then rapidly decompressed in 2 minutes or so to 25,000 feet and removed our masks. One participant immediately felt too dizzy to continue and went on 100% oxygen for the duration. Several others returned to 100% oxygen within the first 3 minutes. 3 minutes is the Air Force maximum time of useful consciousness (TOC). Most participants continued to 6 minutes or more before 1 to 3 signs of hypoxia were noted by the participant or by other participants, or by the instructors and they returned to 100% oxygen. One participant showed euphoria and another had mild tunnel vision. Cognitive tests of memory, math and awareness were made throughout the time at 25,000 feet.

  • I continued without supplemental oxygen for 12 minutes, when I reached the limit allowed by the Air Force. My signs of hypoxia were: lightheaded (immediate at 25,000, but could have partly come from 02 pre-breathing), slight fingertip tingling, then lips were tingling during the last minute or two. One observer thought my fingertips became slightly blue. I was able to correctly do math, answer questions and talk rationally and at length though the 12 minutes. I felt mentally aware and confident. I believe I was able to function well because I live at 9,000 feet and had been regularly paragliding to 17,000 and parachuting from 14,000 - and I may have some physiological and or mental adaptation to altitude due to my 1986-1994 time at high altitude - which includes about 6 days at or above 25,000 feet. It may too, have been my 'lucky day' to go to altitude.

  • We then descended to 18,000 feet and did a vision experiment to experience the hypoxic reduction in vision detail and color. We removed our masks and for about 5 minutes looked at a color chart in normal then in dimmed light. We then viewed the chart while using oxygen to note the improvement in vision.

  • I took my parachuting altimeters in the chamber. The electronic 'AL-Digitude' stopped working at 19,000 feet (0 on the screen) then resumed working on descent. My mechanical altimeter Altimaster III Alez-2 had the same reaction.

  • I went to sleep early the night after the training, sleeping deeply and had some fatigue and minor ear pressure equalizations the following day.

  • The training was arranged via the FAA. An Aviators Class 3 Medical Certificate was a requirement.