1. When wounded, especially with injuries accompanied by hemorrhage or shock.
  2. Above 10,000 feet on day missions, both in training and combat.
  3. From ground up on all night missions.
    1. To prevent night blindness.
    2. Night vision impaired early and to a marked degree at comparatively low altitude.

HAZARD OF OXYGEN-LACK

  1. At 12,000 to 15,000 feet (several hours): fatigue, drowsiness, headache.
  2. At 15,000 to 18,000 feet (½ to 1 hour):
    1. False sense of well being
    2. Overconfidence
    3. Narrowing of field of attention
    4. Faulty reasoning
    5. Poor judgement
    6. Loss of self-criticism
    7. Clumsy
    8. Blurring and double vision
    9. Decreased hearing
    10. Poor memory
    11. May pass out
  3. Above 18,000 feet:
    1. Symptoms come on faster
    2. Loss of muscle control
    3. Loss of awareness of lapse of time
    4. Loss of judgment and self-criticism
    5. Loss of memory and ability to think
    6. Loss of vision and hearing
    7. Purposeless movements, repeated over and over
    8. Emotional outbursts--hysteria, crying, laughing, anger
    9. Loss of consciousness eventually:
      1. at 26,000 feet 4 to 6 minutes
      2. at 28,000 feet 2 to 4 minutes
      3. at 30,000 feet 1 to 2 minutes
      4. at 38,000 feet 30 seconds or less
    10. The above varies with different individuals.
  4. Loss of night vision.
  5. Night vision is reduced to one-half at 12,000 feet without oxygen. Breathing oxygen restores it to normal.
  6. Breathing oxygen raises your ceiling.
  7. ALTITUDE
    FEET
  8. %OXYGEN
    BREATHED
  9. EQUIVALENT
    LEVEL (feet)
  10. 18,000
  11. 60
  12. ground
  13. 26,000
  14. 85
  15. ground
  16. 30,000
  17. 100
  18. ground
  19. 33,000
  20. 100
  21. 8,000
  22. 38,000
  23. 100
  24. 12,000
  25. 44,000
  26. 100
  27. 22,000
ALTITUDE
FEET		%OXYGEN
BREATHED		EQUIVALENT
LEVEL (feet)
18,00060ground
26,00085ground
30,000100ground
33,0001008,000
38,00010012,000
44,00010022,000

REASONS FOR OXYGEN DEFICIENCY AT ALTITUDE

  1. Inadequate supply for the mission. The low pressure oxygen system in the B-17 and B-24 is fully charged to a capacity of 450 pounds per square inch. This supply should last 7 to 9 hours, depending on activity of the crew members (Auto-Mix "ON").
  2. Oxygen supply exhausted by leaks in oxygen lines or cylinders.
  3. Flyer getting insufficient oxygen:
    1. Attempts to do excessively hard work.
    2. Mask leak: Improper fit; frozen exhaust valve; holes in mask or hose; growth of stubby beard.
    3. Leak around gasket between mask-regulator connection.
    4. Loose connections where supply hose connects to regulator.
    5. Freezing of moist oxygen at extremely low temperature.
    6. Obstruction of openings in regulator.
    7. Hole in rubber diaphragm in regulator.
  4. Breathing too deeply may produce a partial vacuum inside mask causing air to leak in from bottom or sides. BREATHE NATURALLY.
  5. Don't expect to get oxygen from an empty walk-around bottle. If not fully charged, the bottle may last only a minute or two.
  6. Improper use of walk-around equipment.

OXYGEN DISCIPLINE

It is mandatory that every member of a heavy combat crew be highly trained in oxygen discipline. It is urged that oxygen "drill" be practiced by ALL crew members for at least 15 minutes on routine training flights before altitude missions are ever undertaken. Practice using and re-filling the walk-around bottle at various stations. Practice changing masks (page 12) and become expert at using oxygen from emergency sources (page 27). Practice reviving some crewmate who has supposedly passed out from oxygen lack. Practice going to your escape hatch on a walk-around bottle with parachute in place. Practice all emergencies that may arise some day in combat and when they arise they won't be emergencies.

The following responsibilities will fall upon every member of a combat crew. The airplane commander should satisfy himself that the following points are observed or provided for:

  1. Fitting of the crew with masks, (page 9). Periodical check of masks and mask fit.
  2. All crew members are familiar with hazards of oxygen-lack at altitude. (page 1).
  3. See that all crew members are drilled in "precautions with the demand system." (page 19).
  4. Be sure that ALL crew members realize the danger of mixing oil and oxygen. (page 50).
  5. Be able to compute oxygen duration in different systems on ship (pages 39 & 46).
  6. PRE-FLIGHT CHECK OF OXYGEN EQUIPMENT.
    1. Pressure in different systems.
    2. Be able to charge oxygen system if necessary. (page 47).
    3. Check regulators for proper setting (auto-mix), properly working diaphragm, hose-regulator connection, emergency valve OFF.
    4. Check EACH station for possible oxygen deficiency at altitude, (page 3).
    5. Check portable oxygen equipment, regulator diaphragm, and oxygen supply in bottles, see that regulators are working properly.
    6. Check all recharger hose valves for sluggish or sticking valves (page 20).
  7. Know how to re-distribute crew members to stations where oxygen is available if part of supply is lost. (pages 41 & 45).
  8. Someone to be able to find and repair a leak in oxygen lines. (page 49).
  9. Frequently check condition of crew members during flight. See that one crew member checks on a fellow crewmate when practicable. Check every 10-15 minutes above 20,000 feet. Co-Pilot can help in this regard.
  10. All crew members understand principles of reviving a crew member unconscious from oxygen lack. (page 51).
  11. Report to crew chief and personal equipment officer on landing any and all faulty oxygen equipment. Make sure repairs to such equipment have been made before next flight.