Appendix
Hypobaric Chamber Flight Profiles
MEDICAL CLEARANCE
A-1. All personnel must have a current flight
physical and a current DA Form 4186 (Medical
Recommendation for Flying Duty) indicating FFD before
participating in any hypobaric chamber exercise.
PURPOSE OF HYPOBARIC TRAINING
A-2. The purpose of hypobaric chamber training is to
safely demonstrate—
- Crew-member limitations associated with hypoxia
at altitude.
- Effects of trapped-gas problems on the
body.
- Effects of hypoxia on night vision.
- Capabilities of oxygen equipment.
CHAMBER PROFILES AND APPLICABILITY OF TRAINING
A-3. Figures A-1 through A-5 show the standard flight
chamber profiles. For information regarding nonstandard
profiles, contact USASAM, ATTN MCCS-HA, Fort Rucker,
Alabama 36362-5377.
The procedures for the profile in Figure A-1 are as follows:
- Begin 30-minute denitrogenation.
- Perform 5,000-foot ear and sinus check by 2,500
feet per minute.
- Ascend main accumulator, and lock to 8,000 feet
by 2,500 feet per minute.
- Ascend main accumulator, and lock to 18,000
feet by 5,000 feet per minute.
- Perform running break of main accumulator and
lock; maintain lock at 18,000 feet.
- Continue main accumulator ascent to 35,000 feet
by 5,000 feet per minute.
- Descend main accumulator to 30,000 feet for
90-second hypoxia demonstration.
- Descend main accumulator, and lock to 25,000
feet by 5,000 feet per minute.
- Begin five-minute hypoxia demonstration.
- Descend lock to ground level by 5,000 feet per
minute.
- Descend main accumulator to 18,000 feet by
5,000 feet per minute for night-vision
demonstration.
- Descend main accumulator from 18,000 feet to
ground level by 2,500 feet per minute.
- Terminate chamber flight.

Figure A-1. Type II 35,000-Foot USAF
Original Training Profile
The procedures for the profile in Figure A-2 are as follows:
- Begin 30-minute denitrogenation.
- Perform 5,000 feet ear and sinus check by 2,500
feet per minute.
- Ascend main accumulator from ground level to
8,000 feet by 2,500 feet per minute.
- Ascend main accumulator from 8,000 feet to
25,000 feet by 5,000 feet per minute.
- Begin five-minute hypoxia demonstration.
- Descend main accumulator from 25,000 feet to
18,000 feet by 5,000 feet per minute for
night-vision demonstration.
- Descend main accumulator from 18,000 feet to
ground level by 2,500 feet per minute.
- Terminate chamber flight.

Figure A-2. Type IV, 25,000-Foot, USAF
Refresher Training Profile
The procedures for the profile in Figure A-3 are as follows:
- Begin 30-minute denitrogenation.
- Perform 5,000-foot ear and sinus check by 2,500
feet per minute.
- Ascend main accumulator from ground level to
8,000 feet by 2,500 feet per minute.
- Ascend main accumulator from 8,000 feet to
25,000 feet by 5,000 feet per minute.
- Begin five-minute hypoxia demonstration.
- Descend main accumulator from 25,000 feet to
18,000 feet by 5,000 feet per minute for
night-vision demonstration.
- Descend main accumulator from 18,000 feet to
ground level by 2,500 feet per minute.
- Terminate chamber flight.

Figure A-3. Type IV, 25,000-Foot, USA
Profile
The procedures for the profile in Figure A-4 are as follows:
- Begin 30-minute denitrogenation.
- Perform 5,000-foot ear and sinus check by 5,000
feet per minute.
- Ascend main accumulator, and lock to 18,000
feet by 5,000 feet per minute.
- Perform running break of main accumulator, and
lock; maintain lock at 18,000 feet.
- Continue main accumulator ascent to 35,000 feet
by 5,000 feet per minute.
- Ascend main accumulator to 30,000 feet for
90-second hypoxia demonstration.
- Descend main accumulator to 15,000 feet by
10,000 to 12,000 feet per minute, with lock joining
descent at 18,000 feet.
- Descend main accumulator, and lock to 8,000
feet by 5,000 feet per minute.
- Ascend main accumulator to 25,000 feet by
maximum rate of ascent.
- Begin five-minute hypoxia demonstration.
- Descend lock to ground level by 5,000 feet per
minute.
- Descend main accumulator to 18,000 feet by
5,000 feet per minute for night-vision
demonstration.
- Descend main accumulator from 18,000 feet to
ground level by 2,500 feet per minute.
- Terminate chamber flight.

Figure A-4. Type V, 35,000-Foot,
USA/USAF HAP
The procedures for the profile in Figure A-5 are as follows:
- Ascend main accumulator to 32,500 feet by
maximum rate.
- Ascend lock to 8,000 feet by 2,500 feet per
minute.
- Perform rapid decompression.
- Main accumulator and lock equalize at 22,500
feet.
- Descend main accumulator; lock to 18,000 feet
by 5,000 feet per minute, then from 18,000 feet to
ground level by 2,500 feet per minute.

Figure A-5. Military Rapid Decompression
Profile