1. Gives a mixture of air and oxygen:
    1. 10,000 feet -- approx. 30% oxygen
    2. 18,000 feet -- approx. 65% oxygen
    3. 26,000 feet -- approx. 85% oxygen
    4. 30,000 feet -- approx. 100% oxygen
    5. Under the above conditions, so far as oxygen is concerned, you are at ground level.
  2. Use oxygen from ground level on night missions to prevent night blindness.
  3. Increased altitude increases oxygen supply AUTOMATICALLY.
  4. Percentage of oxygen delivered keeps you at ground level efficiency.
  5. Ships oxygen supply, charged to 450 pounds lasts 10 men from 7 to 9 hours. (20,000 to 30,000 feet).

AUTO-MIX (AIR) "OFF (or 100% oxygen) -- used when ordered by first pilot, and on special occasions.

  1. Gives 100% oxygen, on demand, regardless of altitude.
  2. Used on special occasions:
    1. To casualties suffering from:
      1. Loss of blood.
      2. Shock.
      3. Passing out from oxygen lack (revived).
    2. Regulator not giving enough oxygen in "ON" position (blue finger nails-beginning to feel pleased with yourself).
    3. To avoid gas poisoning if you land in a gassed area without gas masks.
    4. To flush nitrogen gas from body fluids when going above 30,000 feet, helping to prevent bends.
  3. Ship's oxygen supply, charged to 450 pounds, lasts 6 hours or less.

THE "EMERGENCY" VALVE IS DANGEROUS -- it should be used with extreme caution. A whole system can be depleted of oxygen in an hour or less if the "emergency" is opened only a quarter of a turn. Emergency "ON" changes regulator into a constant flow system and wastes precious oxygen. Use only to revive an unconscious crew member or to check line to make sure it is clear. Always make sure that "Emergency" is TIGHTLY TURNED OFF before ship leaves the ground.

NOTE:

Don't be confused by the difference in appearance of demand regulators manufactured by various companies (see Fig. 9). THEY ALL WORK THE SAME.

PORTABLE OXYGEN EQUIPMENT

A PORTABLE RECHARGER HOSE is available at every station in the ship. Every crew member should know their location so well that they can be located immediately, even on the darkest night. In addition, there is a long recharger hose for filling the ball turret oxygen cylinder. (B-17-F).

When drawing oxygen through a portable recharger the refiller valve must engage the filler nozzle TIGHTLY, otherwise oxygen leaks around the connection and is lost. The oxygen supply of an entire system has been wasted in this manner.

FREEZING or STICKING of refiller valve is not uncommon at extremely low temperatures. Always check this after refilling your walk-around. A stuck valve will quickly deplete the entire supply of oxygen in that system. If the valve is stuck plug in a walk-around bottle and leave it there.