[Transcriber's Note:

Typographical errors (such as "COMAT" appearing for "COMBAT" in
the title) and punctuation inconsistencies have been retained.
The goal has been to provide a historically accurate representation of
the original 1944 publication.]




RESTRICTED

NOTES ON THE USE OF OXYGEN EQUIPMENT
IN THE B-17, B-24, & B-29 FOR COMAT CREWS

*  *  *  *  *  *  *  *  *  *  *  *  *  *

THIS PUBLICATION MAY BE USED BY PERSONNEL RENDERING SERVICE TO THE
UNITED STATES OR ITS ALLIES

Paragraph 5.d. of Army Regulation 380-5 relative to the handling of
"restricted" printed matter is quoted below.

    "d. Dissemination of restricted matter.--The information contained
    in restricted documents and the essential characteristics of
    restricted material may be given to any person known to be in the
    service of the United States and to persons of undoubted loyalty and
    discretion who are cooperating in Government work, but will not be
    communicated to the public or to the press except by authorized
    military public relations agencies."

RESTRICTED




FOREWORD

These notes were originally intended as a source of general reference
concerning OXYGEN EQUIPMENT AND ITS USE by members of crews of the B-17
and B-24 heavy bomber. With the advent of the B-29 as a combat bomber,
the section on THE B-29 AT HIGH ALTITUDE (Page  ) was added to supply
certain specialized information concerning this ship. Every B-29 crew
member should be familiar with the INTRODUCTION and the section on THE
DEMAND OXYGEN SYSTEM as well as this specialized information. The
subject matter is presented from a PRACTICAL point of view, based upon
actual experiences encountered on altitude missions. Detailed
information on oxygen equipment may be found in the following TECHNICAL
ORDERS.

  03-50-1  Use of Oxygen and Oxygen Equipment.
  03-50A-5  Type A-12 Demand Oxygen Regulator (Pioneer).
  03-50A-8  Type A-12 Demand Oxygen Regulator (Airco).
  03-50B-1  Type A-10 Revised Oxygen Mask.
  03-50B-6  Type A-14 Demand Oxygen Mask.
  03-50C-3  Low Pressure Oxygen Cylinders.
  03-50D-1  Oxygen Pressure Signal Assembly.
  03-50D-2  Oxygen Flow Indicator Type A-1.
  03-50D-4  Oxygen Flow Indicator Type A-3.
  03-50D-5  Oxygen Pressure Gage Type K-1.




INDEX

  Auto-Mix  17
  Ceiling, effect of oxygen on  3
  Dangers with oxygen  50
  Demand oxygen system  7
  Demand type masks  8
  Duration of oxygen supply
    B-17  38
    B-24  44
    Method of computing  40
  Emergency valve  19
  Explosive Decompression   61
  Flow indicator  32
  Hazards of oxygen-lack  1
  Leaks in oxygen lines  49
  Leaks in regulator  11
  Mask, Demand
    Fitting to face  9
    Technic, at altitude  13
    Testing for leaks  10
  Mask-Regulator connection  16
  Night Vision  2
  Oxygen cylinders  37
  Oxygen deficiency at altitude  3
  Oxygen installation, Servicing of  47
  Oxygen discipline  4
  Oxygen systems
    B-17  36
    B-24  43
    B-29  57
  Oxygen systems, diagrams of
    B-17  38
    B-24  47A
    B-29  60
  Oxygen equipment, check of  34
  Portable oxygen equipment  20
  Precautions with demand system  34
  Passing out at altitude  51
  Pressure Cabins, B-29  56
  Regulator, Demand
    A-12  17
    A-13  20
  Regulator hose clip  16
  Revival of passout victim  51
  Servicing oxygen installations  47
  Signal assembly  32
  Sniff-tester  11
  Testing for mask leak  10
  The B-29 at High Altitude  53
  Walk-around bottle  20
  Walk-around bottle
    Uses of  20
    Large, for engineer  25
  When to use oxygen  1




INTRODUCTION

    As a member of a heavy bomber team, in combat you will be living and
fighting in a world where man has no business--from three to six miles
above the environment for which nature designed you.

    Successful and effective operation of combat crews at altitudes in
excess of 15,000 feet requires that EVERY crew member be familiar with
altitude problems. You must be so thoroughly familiar with your oxygen
equipment that you will use it PROPERLY without giving it a thought. The
time to acquire this experience is during operational training--not
after you have pulled several boners in combat.

    Through long hours of tiring training you have developed superior
judgment, ability to make decisions quickly, and efficiently in firing
and in other duties. Most of your training has been confined to
relatively low altitudes in a relatively "normal" environment. Now you
are going to continue this training "upstairs". To maintain the
superiority and efficiency you possess OXYGEN MUST BE USED above 10,000
feet. Above 18,000 feet oxygen must be used to maintain consciousness
and life itself.

WHEN SHOULD FLYERS USE OXYGEN?

   (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.
        (a) To prevent night blindness.
        (b) 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):
         False sense of well being
         Overconfidence
         Narrowing of field of attention
         Faulty reasoning
         Poor judgement
         Loss of self-criticism
         Clumsy
         Blurring and double vision
         Decreased hearing
         Poor memory
         May pass out

   (3) Above 18,000 feet:
         Symptoms come on faster
         Loss of muscle control
         Loss of awareness of lapse of time
         Loss of judgment and self-criticism
         Loss of memory and ability to think
         Loss of vision and hearing
         Purposeless movements, repeated over and over
         Emotional outbursts--hysteria, crying, laughing, anger
         Loss of consciousness eventually:
             at 26,000 feet 4 to 6 minutes
             at 28,000 feet 2 to 4 minutes
             at 30,000 feet 1 to 2 minutes
             at 38,000 feet 30 seconds or less
         The above varies with different individuals.

   (4) Loss of night vision.
         Night vision is reduced to one-half at 12,000 feet without
         oxygen. Breathing oxygen restores it to normal.

   (5) Breathing oxygen raises your ceiling.

        ALTITUDE   %OXYGEN            EQUIVALENT
          FEET     BREATHED           LEVEL (feet)
        18,000        60                ground
        26,000        85                ground
        30,000        100               ground
        33,000        100                8,000
        38,000        100               12,000
        44,000        100               22,000




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:

       (a) Attempts to do excessively hard work.

       (b) Mask leak: Improper fit; frozen exhaust valve; holes in mask
           or hose; growth of stubby beard.

       (c) Leak around gasket between mask-regulator connection.

       (d) Loose connections where supply hose connects to regulator.

       (e) Freezing of moist oxygen at extremely low temperature.

       (f) Obstruction of openings in regulator.

       (g) 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.

    (a) Pressure in different systems.

    (b) Be able to charge oxygen system if necessary. (page 47).

    (c) Check regulators for proper setting (auto-mix), properly
        working diaphragm, hose-regulator connection, emergency
        valve OFF.

    (d) Check EACH station for possible oxygen deficiency at altitude,
        (page 3).

    (e) Check portable oxygen equipment, regulator diaphragm, and
        oxygen supply in bottles, see that regulators are working
        properly.

    (f) 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.




THE DEMAND OXYGEN SYSTEM

    The "demand" oxygen system in your ship insures a fully adequate
oxygen supply except under the most extreme conditions. It was developed
to supply you, AUTOMATICALLY, as much oxygen as you need when you need
it--at all altitudes and under all conditions.

The DEMAND OXYGEN SYSTEM consists of the following:

  (1) Demand type mask.

  (2) Mask to regulator tubing.

  (3) Demand type regulator (A-12).

  (4) Portable recharging hose (for filling walk-around bottles

  (5) Portable equipment:
      (a) A-4 Cylinder with A-13 demand regulator.
      (b) D-2 cylinder with A-13 regulator.

  (6) A panel containing:
      a flow indicator
      an oxygen pressure gauge

  (7) Cylinders containing breathing oxygen.




DEMAND TYPE MASKS

Styles: A-10A and A-14

    The A-10 mask is obsolete.

    The A-10 revised mask is obsoete.

    The A-14 mask is standard issue for staging and combat areas, and
operational or replacement training schools.

    The A-10-A mask is used in training where sufficient A-14 masks
are not available.

    Both the A-10-A and the A-14 masks are suspended from the summer
and winter flying helmets.

    NOTE: It is important that AERIAL GUNNERS obtain a properly fitting
mask, fit to both summer and winter helmets at the first station
available. Because of the extreme cold to which gunners are subjected
under combat conditions, you MUST learn to remove and replace the mask
quickly and accurately WEARING HEAVY GLOVES. It is not easy to
manipulate a mask or unjam a .50 cal. gun with numb fingers in heavy
flying gloves. PRACTICE these things on every training flight with
gloves ON.

FITTING THE MASK TO THE FACE -- There are two considerations in
obtaining a proper fit:
  (1) An _AIR-TIGHT SEAL_ of mask to face.
  (2) Comfort of fit without undue pressure.

    The A-10-A and A-14 masks come in three sizes. Roughly, 60% of
flyers will require the STANDARD (medium) size mask, 30% the LARGE mask,
and the remaining 10% the SMALLER sizes. General instructions concerning
fitting are.

(1) Suspension points on both summer and winter helmets must be
determined INDIVIDUALLY on each flyer. This is a job for your squadron
personal equipment officer or the group aviation physiologist or his
trained assistant.

(2) It is important that the mask be suspended _high_ on the face,
sealing to the boney portion of the nose and cheek bones and NOT
the soft tissues. Otherwise you'll get a leak or a "clothespin on
the nose" effect from pressure of the nose wire.

NOTE:

    (a) Be sure the regulator hose clip or the clip on the walk-around
    bottle is clipped high enough on your clothing to remove all
    tension from mask hose--otherwise the mask will be pulled down
    on the face and will leak outside air.

    (b) Above 25,000 feet with the temperature 20 degrees and lower, the
    tissues of the face contract and the rubber mask loses its
    pliability. Under these conditions, the mask tends to fall away
    from the face and it becomes necessary to SHORTEN THE UPPER
    SUSPENSION STRAPS. On returning to warmer altitudes, these must
    be loosened again to avoid discomfort from a too tightly fitting
    mask. (Applies chiefly to gunners).

(3) Excessive beard stubble will hold the mask away from the face and
cause leak around the jaws.

(4) See page 35 for care of mask.

(5) TESTING FOR LEAKS -- Holding the thumb over the end of the mask tube
(rapid disconnect) and inhaling GENTLY should cause the mask to collapse
on the face. The most common place for a leak is alongside the bridge of
the nose. The actual site of leak is determined by putting finger-point
pressure beside the nose and over the cheek bones, one point at a time.
The nose wire is then re-adjusted to cause pressure at this point. Be
sure the mask is high enough on the face and on the bridge of the nose.
If the seal is still below the boney portion of the nose try the next
largest size mask.

(6) "SNIFF-TESTER" -- An effective "sniff-tester" for detecting small
leaks can be obtained as follows: Obtain one of the commercial nasal
inhalers - Benzedrine, Vick's, Penetro (or metal tube of comparable
size). Cut off the end ordinarily inserted into the nose flush with the
barrel of the container, and remove contents. Fit barrel with an
airtight cork stopper. Straighten a paper clip or take a piece of wire
of similar gage, cut to 2½ inch length, and drive one end firmly into
lower side of cork stopper. Fashion other end of wire into a 1/4 inch
fish hook bend. Make a ball of cotton or tightly wrapped gauze, ½ inch
in diameter, and attach to bent end of wire. Soak the cotton or gauze,
in oil of peppermint or oil of cloves (obtained from squadron dentist or
flight surgeon) and fit cork stopper, carrying the "sniff-tester"
tightly into metal container. To "sniff-test", remove the stopper and
hold the cotton plug on both sides of the nose at the top of the mask
(eyes closed). Inhale gently with the mask hose blocked. A leak is
present if the contents of the "sniff-tester" is detected. Rough as this
test seems, it is very sensitive.

NOTE: The "sniff-tester" is also effective in testing the DEMAND
REGULATOR for leaks. Put on mask. Fit snugly to face. Plug into
regulator hose. Turn Auto-Mix (Air) Lever OFF. Hold sniff-tester close
to regulator diaphragm and breathe normally several times. If the
contents of the sniff-tester" are detected, the regulator has a leak.

TWO TYPES OF "SNIFF-TESTERS"

(A) Cotton pledget soaked with oil of peppermint.

(B) Benzedrine inhaler containing blotter soaked with oil of peppermint.

[Illustration: Fig. 1]

REMOVING MASK AT ALTITUDE -- There are many reasons why your oxygen mask
will be removed above 20,000 feet. This has been responsible for
countless "accidents" in heavy bomber crews IN advanced training and in
combat. LEARN THE PROPER TECHNIC NOW, wearing heavy gloves. You can take
your oxygen mask off at 30,000 feet and be as safe as you are on the
ground, PROVIDING YOU HOLD YOUR BREATH and don't breathe the "thin"
outside air. The following are a few of the reasons why you will remove
your mask at high altitude. DON'T REMOVE YOUR GLOVES, for freezing
occurs almost instantaneously and painlessly at temperatures of 30 below
and lower.

(1) To wipe moisture from inside the mask at regular intervals -- for
comfort and to prevent ice formation around exhaust valve.

  NOTE: A puddle of condensed moisture lying over the flutter
  valve will render it useless. You will be warned of this; when
  you breathe out, the air from your mask comes out the top of the
  mask, fogging your goggles.

(2) To blow your nose. To help clear your ears on descent by holding
nose and blowing (if necessary). To vomit if you get sick.

(3) To take nourishment and hot drinks on missions.

(4) To change masks.

TECHNIC -- NEVER breathe when mask is off face or is loosened from
helmet. PRACTICE THIS with a mirror: (See Fig. 2, 3 & 4)

(1) Hold mask to face firmly with left hand.

(2) Disengage mask clip from helmet with right hand.

(3) Holding mask snugly in position with left hand, take 3 or 4 deep
breaths of oxygen.

(4) Remove mask with left hand, HOLDING BREATH. The right hand is free
to service mask, to blow nose or to administer food or drink. Hold mask
in left hand.

(5) When you have to breathe, reapply mask to face making sure it is
held snugly along sides of nose with index and middle finger of left
hand, one on each side. of nose (hold mask in palm of hand with index
and middle finger making a V, one on each side of the nose piece).

(6) Take 4 or 5 deep breaths from the mask and repeat #4. This procedure
may be kept up indefinitely with complete safety, providing you DON'T
BREATHE OUTSIDE AIR.

[Illustration: Fig. 2 MASK TECHNIC (1)]

[Illustration: Fig. 3 MASK TECHNIC (2 & 3)]

[Illustration: Fig. 4 MASK TECHNIC (4)]




MASK TO REGULATOR CONNECTION (RAPID DISCONNECT)

IS THE RUBBER GASKET IN PLACE? Without the gasket an air-tight seal at
this joint is impossible. Dangerous oxygen-lack will result above 24,000
feet. With a leak at this altitude serious mental and physical
inefficiency will develop, even though you may not pass out. Above
28,000 feet you will quickly become punch drunk, and the pass-out will
soon follow.

USE THE CLIP ON THE REGULATOR TUBING--It is there to remove tension on
this connection which could (1) cause serious mask leak by pulling the
mask down on the face, or (2) cause mask tubing to become disconnected.
In combat these things would fail to attract your attention. Without
warning you are first slap-happy and then drop unconscious.

THE RAPID DISCONNECT REQUIRES CONSTANT ATTENTION whether you are plugged
into a fixed station or into a walk-around bottle. A pull of at least 12
pounds should be required to separate the male and female connection of
the rapid disconnect. The security of the connection can be increased by
spreading the groups at the tip of the male connection. (See diagram,
pre-flight check, page 39).

CONNECTION OF HOSE TO REGULATOR IS NOT A SWIVEL JOINT--Above 24,000 feet
the collar must be turned up tightly to prevent a dangerous leak of air.

Make sure that the regulator hose is wired securely to the goose neck on
the regulator.




THE DEMAND (A-12) REGULATOR

    In principle the demand regulator is a diaphragm-operated flow valve
which is opened by the user's inspiration and closes automatically when
the suction ceases. This gives you as much oxygen as you ask for. All
you do is breathe. A short breath draws a short squirt of oxygen, while
deep, rapid breathing brings forth large shots in rapid succession.

    The regulator can be set to conserve oxygen, or to give you 100%
oxygen, regardless of the altitude you are flying. This is governed by
the position of the "Auto-Mix" (AIR) lever.

    AUTO-MIX (AIR) "ON" (or NORMAL OXYGEN) is the position for routine
use. This saves oxygen.

(1) Gives a mixture of air and oxygen:

    10,000 feet -- approx. 30% oxygen
    18,000 feet -- approx. 65% oxygen
    26,000 feet -- approx. 85% oxygen
    30,000 feet -- approx. 100% oxygen

    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:

    (a) To casualties suffering from:
        1. Loss of blood.
        2. Shock.
        3. Passing out from oxygen lack (revived).

    (b) Regulator not giving enough oxygen in "ON" position (blue
        finger nails-beginning to feel pleased with yourself).

    (c) To avoid gas poisoning if you land in a gassed area without gas
        masks.

    (d) 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.

    USES OF THE WALK-AROUND BOTTLE -- (1) As an ACCESSORY REGULATOR --
the A-13 regulator on the walk-around bottle is a demand type regulator
without the "auto-mix" feature. It gives 100% oxygen on inspiration
regardless of the altitude. By connecting the walk-around bottle FIRMLY
into the portable recharger valve, one has an extra source of oxygen at
that particular station. As long as the oxygen gauge at the station
registers oxygen pressure the user is assured a supply of pure oxygen
... his supply is coming directly from the system. Remember this when
reviving a passed out crew mate in the waist in the vicinity of the ball
turret--the long recharger hose used to charge the oxygen bottle on the
ball turret can be plugged directly into a walk-around bottle attached
to the unconscious crew member's mask.

    If other long recharger hoses can be obtained from Tech Supply they
will be extremely handy attached at the pilots station, in the bomb bay
and to the recharger outlet at the right waist gunner's station. This
would permit the engineer, who in flight is continuously filling his
walk-around bottle, considerable liberty. He could cover most of the
ship, staked out on a long recharger hose connected to his walk-around
bottle. It would also provide a readily accessible source of oxygen to
revive crew members who pick such out-of-the-way places to pass out as:
the bomb bay cat-walk, the bomb bay doors, under the flight deck, or in
some remote part of the waist.

    One or two extension portable recharger hoses shown in photograph
page 22 should be standard equipment in heavy bombers.

[Illustration: Fig. 5 EXTENSION RECHARGER HOSE]

(2) SOURCE OF OXYGEN FOR BAIL-OUT -- Above 20,000 feet, breathing of
oxygen is necessary to reach your particular escape hatch. After this
spot is gained you won't need oxygen ... unless you start fiddling with
the rip-cord too soon. Go to your exit on the walk-around bottle, fill
your lungs deeply five or six times from the bottle, HOLD YOUR BREATH,
and take the dive. Continue to hold your breath during the descent as
long as possible. By the time your lungs are bursting for air you'll be
from 8 to 10,000 feet nearer the ground and won't need extra oxygen.
Leave the mask on--it will protect your face. If the skies are filled
with enemy planes it may be wise to continue the free fall. By now you
can start breathing without danger of serious oxygen-lack. Any dimming
of mental acuity would be of such short duration that you'd have plenty
of time to pull the ripcord.

PRACTICE GOING TO YOUR ESCAPE HATCH ON A WALK-AROUND BOTTLE DURING
OPERATIONAL TRAINING -- PRACTICE ON JUST HOW YOU WOULD CLEAR THE SHIP --
GO THROUGH ALL OF THE ROUTINE EXCEPT THE BAILOUT and that might not be
time wasted, at least just once before the time comes when you might
have to!

    Above 30,000 feet you wouldn't want to open your 'chute even if you
had plenty of oxygen. You'd freeze a hand or foot or both if you did.
Under these conditions you'd free fall, holding your breath, as long as
possible. Then, after three or four breaths of "thin" air, pull the rip
cord. Your altitude should be in the vicinity of 10,000 to 12,000 feet
below that when you abandoned ship, and the degree of oxygen-lack
encountered here wouldn't be of dangerous consequence. You'll avoid
freezing, and perhaps the gunfire of enemy interceptors.

(3) TO MOVE ABOUT THE SHIP For this the walk-around bottle is very
useful ... and very tricky! The trouble is that the thing is good only
as long as it gives oxygen. It will rarely, if ever, be fully charged so
forget that 8 to 12 minute stuff. You can't fill your bottle any fuller
than the pressure in the line you'll be drawing from. And the only time
that will be fully charged is when the ship is on the ground, freshly
charged with oxygen, ready for the take-off. When you need the
walk-around bottle, three or four hours will have passed ... and the
pressure in your filling line will be some fraction of the full charge.
As a rule you'll do well to get the bottle half charged. And you're
going to be moving about at altitude and needing 3 to 5 times as much
oxygen as if you were sitting quietly in a corner. So plan on the
walk-around supply lasting 1½ to 2 minutes ... then you won't be caught
short Refill the bottle frequently. Refill it every time you pass a
portable recharger hose ... and there's one at every station. Failure
to do this has caused more pass-outs in second and third phase training
than any other single cause ... unless you include carelessness. And
careless people don't last long in the kind of work you're specializing
in! There's a check-valve on the walk-around bottle, so you won't lose
anything if you plug into a system that reads less than the gauge on the
bottle.

NOTE TO ENGINEERS: Because of its limited supply, the standard
walk-around bottle is next to useless for many of your jobs which must
be done in flight on a walk-around bottle. The ENGINEER NEEDS A LARGER
WALK-AROUND BOTTLE. One, having a supply 5 TIMES AS GREAT as the
standard portable cylinder, can be obtained as follows:

    Obtain a D-2 oxygen cylinder (stock No. 5500-344020 - class 03K)
from Air Corps Supply. Remove the A-13 regulator assembly from a
standard walk-around bottle. Remove the spud from one end of the D-2
cylinder and screw the A-13 regulator in tightly. Fill to 400 p.s.i. and
leave overnight to determine if pressure is maintained or lost due to a
leak. (A drop of 25 to 50 pounds will occur in the absence of a leak due
to cooling of the oxygen which warmed up when the cylinder was charged).

[Illustration: Fig. 6 D-2 WALK-AROUND BOTTLE]

    For leaks here or elsewhere in an oxygen system use the following
anti-sieze and sealing compound on the pipe threads: Pioneer Antisieze
No. 2., Class 96B, Stock no. 7500-050800. Never use a sealing compound
which contains oil.

    A satisfactory bag with shoulder strap for carrying the walk-around
bottle when in use can be made from heavy twill or canvas by the
parachute department.




EMERGENCY OXYGEN EQUIPMENT

    In addition to your ship's regular oxygen supply, you will take
emergency oxygen rations along on combat missions. If practical you will
also have several extra masks on board. Know where they are stored.

(1) Both of the low pressure walk-around bottles should be kept as full
as possible-- you never know when you may need them. If full, the small
walk-around bottle is good for only a few minutes, the large for 30 to
45 minutes, depending on your activity.

(2) High pressure equipment.

a. A-2 bottle with bag-mask. (Fig. 7)

     In some theaters each combat crewman is issued this equipment. The
   high pressure bottle is fully charged to 1800 and will last
   approximately 45 minutes to one hour. It is used with the continuous
   flow mask.

[Illustration: Fig. 7 A-2 OXYGEN BOTTLE WITH BAG MASK]


b. Bail-out bottle. (Fig. 8)

      This small high pressure cylinder is a "last resort" source of
    emergency oxygen. It contains approximately 12 minutes supply. The
    old style bottle (H-1) is equipped with a pipe stem which is held
    between the teeth. A newer bail-out bottle (H-2) has a bayonet
    connection so it can be used with an A-14 mask with bail-out adapter
    (see fig. 8).

[Illustration: Fig. 8 BAIL OUT BOTTLES]




PRESSURE GAGE

    Your oxygen pressure gage registers from 450 pounds to zero. WATCH
YOUR PRESSURE GAGE! Except under extreme emergency, don't run the
pressure down under 50 pounds .... if you do there's danger of moisture
getting into your refiller line. Then the next time you go to high
altitude you'll have trouble with freezing in the oxygen line.




FLOW INDICATOR

    Either the bouncing ball or blinking eye will be at each station,
depending on the vintage of your ship. Only older ships will be equipped
with the bouncing ball which is no longer manufactured. These indicators
do not tell HOW MUCH oxygen you are getting ... they merely indicate
that some oxygen is flowing through the system when you take a breath.
They may be working O.K. even though your oxygen supply is inadequate.
The COLOR OF YOUR FINGER NAILS is a better guide to the amount of oxygen
you are getting, providing your hands are warm. If they become bluish
above 20,000 feet check mask and connections for leak. Naturally, you
won't remove your gloves to look at your finger nails if the temperature
is 20 or 30 degrees below zero. If no leak is found, switch the
"Auto-Mix" to the OFF position and note if things improve. INFORM YOUR
PILOT IF AUTO MIX IF LEFT "OFF" and your mission is a long one.

[Illustration: Fig. 9]

[Illustration:
  PRE-FLIGHT CHECK
  1--MASK. fit and check washer
  2--CONNECTION. 12 lb. pull; adjust prongs to fit snugly
  3--HOSE CLAMP
  4--REGULATOR. diaphragm; knurled nut tight
     auto-mix on; smooth motion; emergency off
  5--PRESSURE within 50 lbs. of initial pressure; within 25 lbs
     of other gauges.
]

IN THE AIR:

(1) Check for leak by blockage and gently inhalation each time mask is
removed and replaced.

(2) Check oxygen flow indicator at regular intervals. Also, CHECK COLOR
OF NAILS AT REGULAR INTERVALS -- if blue above 20,000 feet turn Auto-Mix
to "OFF" position.

(3) Check oxygen pressure gauge frequently.

(4) If temperature is below freezing, manipulate mask to free it of ice
at regular intervals. Wiping moisture from mask periodically will
prevent freezing of mask.

(5) Open EMERGENCY flow only when absolutely necessary ... notify pilot.

(6) Over 28,000 feet switch Auto-Mix to "Off" position ... turn back to
"ON" position below this altitude.

(7) Re-fill walk-around bottle frequently when you are using it at
altitude.

(8) Avoid unnecessary exercise above 20,000 feet ... take your time!

(9) Observe your fellow crew member at frequent intervals above 20,000
feet. You can recognize before he can if he's in trouble.

ON RETURN TO FIELD

(1) Wipe mask dry. It should be thoroughly cleansed with soap and water
(inside) after 10 to 14 hours use. Be sure that exhaust flutter valve is
kept clean.

(2) Inspect mask for leaks or cracks in face-piece.

(3) Change strap adjustment only to take up natural stretch slack.

(4) Lend your mask only in extreme emergency.

(5) Protect your mask from hot sun, moisture, and rough treatment.

(6) Report all defective oxygen equipment to ground crew and to personal
equipment officer immediately on landing. See that it has been repaired
or replaced before another altitude mission.




OXYGEN SYSTEMS IN THE B-17

    The Army Air Forces use the low pressure system (maximum charge 450
pounds per square inch) in preference to the high pressure system (1800
pounds per square inch) for these reasons:

        (1) Cylinders do not explode when hit.

        (2) Do not "rocket" from moorings when hit.

        (3) Less chance for fire or flash burns.

    A diagrammatic sketch of the FOUR different oxygen systems is shown
on page 38. EVERY crew member should thoroughly familiarize himself with
the location of each regulator and each portable recharger hose.

    The four systems, arranged two on a side, offer great advantages in
combat over a single system. It is possible to redistribute crew members
whose system has been shot out and stay in formation. Everyone must know
these alternate positions. (page 41 for B-17, page 45 for B-24).




OXYGEN CYLINDERS

NOTE: Based on combat experiences, continuous changes are being made in
the oxygen systems and oxygen supply in heavy bombers. The following
considerations apply only to the type of ship specified. Newer models
and ships modified at staging areas may be different both in arrangement
and number of oxygen cylinders. KNOW the oxygen supply for YOUR STATION
IN YOUR SHIP.

    Two types are found in the B-17. EIGHTEEN G-1 cylinders contain the
main supply which is distributed through the four systems. All are
filled through a single recharging line.

    The G-1 cylinder has a volume of 2100 cubic inches and contains 30
cubic feet of oxygen when charged to a pressure of 450 pounds per square
inch. In combat the cylinders are charged to 450 pounds or better (all
cylinders have been tested to withstand 700 pounds pressure). Each
cylinder is check-valved so that one of a bank of cylinders may be shot
out with loss of no oxygen from the remaining intact cylinders. Between
20,000 and 30,000 feet, one G-1 cylinder charged to 450 pounds will last
one man approximately 5 hours (Auto-Mix "on").

TURRETS:

    The turrets on the earlier models (B-17F) are supplied with F-l type
cylinders having a capacity of approximately 14 cubic feet when fully
charged to 450 pounds. Under these conditions a fully charged bottle
lasts one man approximately 2 hours. (Note: these bottles are recharged
from the ship's supply during flight, so it will not be possible to
fully charge them after several hours of flight on oxygen. They will be
no fuller than the pressure in the system from which they are
charged--front left system for top turret; rear left system for ball
turret).

[Illustration: Fig. 10 OXYGEN SYSTEMS B-17G]

    B-17G models are modified so that the turrets are supplied oxygen
directly through a flexible hose -- the top turret from the front left
system -- the ball turret from the rear right system. The same changes
may be found in the ball turret of the B-24.




COMPUTING OXYGEN DURATION

    Several members of the crew must be able to calculate the duration
of the oxygen supply. The following simple procedure will permit a
fairly accurate estimate of each systems duration. The figures are based
on altitudes between 20,000 and 30,000 feet where the majority of your
combat flying will take place.

G-1 CYLINDERS -- full charge 450 pounds -- each cylinder equals 5 man
hours.

FORMULA: 5 (man hours) x number of intact cylinders x actual
         pressure/400 divided by number of men using oxygen from
         system = DURATION in hours.

Examples:

  FRONT LEFT SYSTEM - 5 cylinders -- full charge to 450 pounds = 25
  man hours.

    3 intact cylinders (2 shot out), pressure 200 pounds, pilot and
    navigator on system.

    5 x 3 x 200/400 x 1/2 = 3 plus hours.

    For 3 men:

    5 x 3 x 200/400 x 1/3 = 2 plus hours.

  FRONT RIGHT SYSTEM: 4 cylinders - full charge to 450 pounds = 20 man
  hours.

  Example:

    4 cylinders, pressure 160 pounds, bombardier, co-pilot, and
    engineer on system.

    5 x 4 x l60/400 x 1/3 = 2½ plus hours

  LEFT REAR SYSTEM: 6 cylinders - full charge to 450 pounds 30 man
  hours.

  Example:

    6 cylinders, pressure 200 pounds, radio operator ball turret
    gunner, left waist gunner and tail gunner on system.

    5 x 6 x 200/400 x 1/4 = 3⅔ hours

  RIGHT REAR SYSTEM: 3 cylinders - full charge to 450 pounds 15 man
  hours.

  Example:

    3 cylinders, pressure 300 pounds, two men on system.

    5 x 3 x 300/400 x 1/2 = 5 plus hours

    Left rear system out - RO, ARO, AE and two AG's on right rear
    system.

    5 x 3 x 300/400 x 1/5 = 2 hours.

  F-1 CYLINDER -- ball turret -- full charge to 400 pounds 2 plus hours

    2 (man hours) x 120/400 = 0.5 plus hours (30 plus min)




ALTERNATIVE POSITIONS IN EMERGENCY (B-17G)

Left front system out:

    Navigator on walk-around bottle plugged into Bombardier's recharger
    hose. Pilot uses Engineer's regulator hose from right front system.

Right front system out:

    Bombardier on walk-around bottle plugged into Navigator's recharger
    hose. Engineer same on Pilot's recharger hose. Copilot on top turret
    regulator hose (hose too short in later models).

Left rear system out:

    RO on one regulator from across aisle.

    ARO on regulator right radio compartment.

    AE on walk-around bottle on recharger hose, right radio compartment.

    AG on waist regulator, right.

    AG on tail regulator, right.

Right rear system out:

    RO regular position.

    ARO on bomb bay regulator.

    AE on walk-around bottle plugged to ball turret recharger hose.

    AG on waist regulator, left.

    AG on tail regulator, left.




OXYGEN SYSTEM IN THE B-24

    Like the B-17, the B-24 is equipped with a low pressure oxygen
system. Location of the cylinders and distribution of the lines,
however, is entirely different. The oxygen system varies somewhat in
the different model ships and in individual ships. In the B-24 D
(beginning with Serial No. 42-40218) to the B-24 H, however, the system
is essentially as described below. Some of the minor variations will be
noted, including changes to the supply for the nose positions in late T
models. FAMILIARIZE YOURSELF WITH THE OXYGEN SYSTEM IN YOUR OWN SHIP.

OXYGEN CYLINDERS:

    There are 22 type G-1 cylinders arranged in eight systems (see
diagram on page 47B). Sixteen cylinders are banked above the bomb-bay.
The remaining six are buried in the floor of the rear fuselage
compartment. There are also two smaller (type D2) cylinders attached to
the chair of the top-turret gunner. These are not connected to the main
system but must be charged from a portable recharger line. The main
system is charged from a single filler valve located in the left side of
the bomb bay. Each G-1 cylinder, when charged to 450 pounds per square
inch, contains 30 cubic feet of oxygen, and will last one man
approximately 5 hours between 20,000 and 30,000 feet (Auto-Mix "on").

DISTRIBUTION SYSTEMS:

    The systems differ radically from those of the B-17. In models up
through H to early J each individual draws from at least two or three
cylinders. With the exception of the nose positions there is a maximum
of two men on the same system. As shown in the diagramatic sketch (page
47B), the pilot, co-pilot, side gunners, and tail gunner each have their
own individual system of at least two G-1 bottles.

    In the G, H and early J series the three regulators in the nose are
supplied by a single system containing only three oxygen cylinders.
(diagram page 47B). This is inadequate. The later J models have a
modified system to the nose wherein the bomb bay - radio operator system
is Tee'd into the supply to the nose positions. This brings to a total of
six oxygen cylinders for the five stations. (diagram page 47A). Since
the regulators at the radio operator and bomb bay stations are not used
continuously during combat missions, this modification to the nose
positions is adequate. Further, the connections in the lines leading to
the nose are such that the nose positions are supplied individually as
well as collectively so that loss of the supply to one system does not
necessarily deplete the other systems. KNOW THE OXYGEN SYSTEM IN YOUR
SHIP.

    The bottom turret and camera tunnel regulators are supplied by the
same system containing three cylinders.

ALTERNATIVE POSITIONS IN EMERGENCY:

    In case of loss of the entire oxygen supply of any one system, the
affected crew member may move to any other convenient regulator in the
ship with these exceptions:

  (1) The nose gunner may not move to the navigator-bombardier regulator
      if the entire system is out.

  (2) The radio operator may not move to the bomb-bay regulator if the
      entire system is out.

  (3) The bottom turret gunner may not move to the camera tunnel
      regulator.

This is true because every station, with these three exceptions, has its
own individual oxygen supply. The use of the walk-around bottle is the
same as that described for the B-17. (Page 20).

DURATION OF OXYGEN SUPPLY:

    With the present system in the B-24, each man has approximately 9
hours oxygen supply at 30,000 feet with the Auto-Mix on. However, it
occasionally becomes necessary in emergencies to calculate the residual
oxygen supply. This can be done by the simple formula given on page 24:

    5 (man hours) x no. of intact
    cylinders x actual pressure/400
    divided by no. of men using the system.

    Application of this formula is much simpler in the B-24, since
usually only one, and at the most two, men are using a single system.

VARIATIONS:

    The exact location of the demand regulators in a ship is variable,
depending upon the model, place of installation, etc. It is extremely
important that you familiarize yourself with the location of the
regulators in your ship, so that you can move from one to the other in
darkness, in case of emergency. Many of the B-24 H models have two extra
regulators: one in the nose, and one in the tail. There is also
variation in the location of the portable recharging hose for the
top-turret bottles. This is located in the right side of the ship in
most earlier models, but in the left side in later models.
Fundamentally, however, the system in all ships commencing with No.
42-40218, is as described above. It is up to you to familiarize yourself
with any minor differences in your ship.

[Illustration: Fig. 11 OXYGEN SYSTEM B-24J MODIFIED]

[Illustration: Fig. 12 OXYGEN SYSTEM B-24D to H]




SERVICING THE OXYGEN INSTALLATION IN THE B-17, B-24 and B-29

CAUTION: Always have a reducing valve between high pressure supply
cylinders and ship's oxygen system.

1.  Attach recharger hoses to cylinders of both turrets in B-17 or B-24.

2.  Open valves on both commercial, high pressure cylinders on recharger
    cart.

3.  Turn in reducing valve on recharging cart to 100 pounds in the low
    pressure gage.

4.  Insert nipple of hose from recharger cart into filler valve of plane
    just inside nose escape hatch (B-17) or left side of fuselage (B-24
    and B-29).

5.  Fully open valve at end of hose and wait until oxygen stops flowing.

6.  Turn up reducing valve on cart to 200 pounds and allow oxygen to
    flow until it ceases. Turn up recharger valve to 300 pounds and
    again wait for ship's containers and supply pressure to equalize.
    Turn up recharger valve to 450 pounds and wait until oxygen flow
    ceases entirely.

7.  Check pressure gauges in ship to make sure that all register in the
    neighborhood of 425 pounds.

8.  Turn off hose valve and remove nipple from filler valve.

9.  Replace cover of filler valve.

10. Disconnect filler hoses from turret tanks.

NOTE: Purifier cartridge should be changed after discharge of every 1.6
      cylinders of oxygen. (T.O. 19-1-2) If this is not observed the
      oxygen will contain moisture and freezing in oxygen system will
      occur at high altitude.

    After the oxygen in the tanks has had time to cool down, pressure
should be in the neighborhood of 400 pounds.

    The same procedure must be employed even if one or more of the
systems is already fully charged since there is no way of equalizing
pressure among the different manifolds. Do not attempt to use any system
in which the pressure is less than 50 to 75 pounds per square inch.
Under these conditions the oxygen flow is very weak. More dangerous is
the possibility of moisture getting into the oxygen line through the
main recharger valve. This will result in freezing in the line or one of
the regulators on the next trip to high altitude.




LEAKS IN OXYGEN LINE

    Leaks in oxygen lines and be detected by painting oxygen tubing with
a paintbrush and solution of soap suds--soap bubbles appear at the site
of leak.

    Connection of oxygen tubing to nipples, elbows, tees, and regulators
are made air-tight by applying an anti-sieze, sealing compound to the
pipe threads (see note, page 27). DON'T use anything containing OIL.

    A good way to check entire oxygen system for a leak is to have
systems charged to 450 pounds the night before take-off. If the pressure
is less than 400 pounds the next morning a leak is present.

    NOTE:

    A 50 pound drop in pressure can be anticipated due to cooling off
    of oxygen after the system is charged.




GENERAL RULES FOR SAFE HANDLING OF OXYGEN

DON'T use oil with oxygen.
    The reaction when these two substances come in contact is more
violent than igniting dynamite. Keep oil or grease away from oxygen
cylinders, cylinder valves, and other equipment. Clean hands of oil or
grease before using oxygen apparatus.

DON'T wear greasy clothes, gloves, etc., when working with oxygen.
Oxygen will cause substances with merely a trace of oil or grease
thereon to burn with great intensity.

DON'T use inflammable substances near oxygen. Oxygen itself will not
burn but will greatly accelerate combustion.




PASSING OUT AT ALTITUDE

    There are two ways to use oxygen equipment at altitude -- a right
and wrong. Don't be a fish out of water when you fly above 18,000 feet.
Learn how to use oxygen the right way NOW - then you won't have to
re-learn the hard way after an unpleasant experience or two.

    A few points on reviving a fellow crew member who has passed out due
to oxygen lack--an opportunity that may well be yours some day!

(1) KEEP CALM -- Just because a man passes out from oxygen lack is no
    sign that he's at death's door. TAKE YOUR TIME. Remember you're
    going to need OXYGEN yourself for the job at hand. If you don't
    heed this, there'll be TWO to revive instead of only one.

(2) PLAN how you're going to revive the victim--then proceed with the
    least possible exertion to yourself.

(3) DON'T attempt to drag or carry the victim to a supply of oxygen.
    If he's not near a regulator hose, take portable oxygen TO him. Take
    plenty -- 3 or 5 bottles -- some for him, plenty for you. If he's
    near a regulator hose you're in luck. Connect his mask and NOW use
    the "Emergency." Ordinarily you'll almost blow him right back onto
    his feet.

(4) GET ASSISTANCE. Have someone keep an eye on you, and supply you
    with refilled walk-around bottles if needed.

(5) Connect the victim to a walk-around bottle. Ordinarily he'll come
    to in a matter of seconds. But watch him. He'll be punch drunk and
    confused as to what's going on.

(6) After he's emptied one bottle, give him another. Then put him on a
    third and assist him ON HIS OWN POWER to a regulator. Turn the
    Auto-Mix "OFF" and let him breathe pure oxygen for 5 or 10 minutes.
    Ordinarily he'll be able to return to his regular duties.

(7) If the victim has been out for a number of minutes he may present
    more of a problem. Breathing becomes shallow -- and the demand
    system gives just what is asked of it -- a weak inspiration brings a
    small squirt of oxygen. So, you'll have to help him with artificial
    respiration, learn it -- your flight surgeon will show you how.

Caution: Above 20,000 feet, get assistance to give artificial
respiration. It will be strenuous work -- a job for several men, not
one. Take turns of one to three minutes each.




THE B-29 AT HIGH ALTITUDE

[Illustration]

    The B-29 is designed to permit you to fly at high altitude without
the usual disadvantages of extreme cold, diminished pressure, and
decreased oxygen. This is done by the use of pressurized, heated
compartments. A highly efficient oxygen system is also incorporated in
the ship for use when the cabins are unpressurized.

[Illustration: Fig. 13]




PRESSURE CABINS

    There are three pressure compartments in your ship: Forword, Aft,
and Tail. (See Fig. 13). The forward and aft cabins are connected by a
communicating tunnel running over the bomb-bay; the tail compartment is
isolated when pressurized.

OPERATION: The cabins are pressurized from the superchargers of the two
inboard engines. Your flight engineer controls the air-flow from these
superchargers, permitting the cabin Pressure Regulators to automatically
regulate the air pressure within the cabin. From ground level to 8,000
ft the cabins are not pressurized. When the cabins are under pressure,
your cabin altitude will remain at 8,000 ft, while the ship is flying at
any altitude up to 30,000 ft. When your ship gets about 30,000 ft, the
cabin pressure will rise proportionately so that it reaches about 12,000
ft when the ship is at 40,000 ft. (See Fig. 14 for this pressure
relation). Cabin temperature is controlled by thermostat.

[Illustration: Fig. 14]

EMERGENCY PRESSURE RELEASE. Since all emergency doors open in, cabin
pressure must be released in all emergencies. This is done by a valve
controlled by cable from:

  1. Pilot's seat

  2. Behind R.H. side gunner

WHEN DO YOU NEED OXYGEN IN A B-29?

    As long as the cabin altitude is below 10,000 ft you're O.K. without
oxygen.

    YOU MUST USE OXYGEN when the CABIN ALTITUDE goes ABOVE 10,000 feet.

This may occur:

  1. When you are flying unpressurized.

  2. If you fly above 35,000 feet.

  3. Following explosive decompression (Blown blister).

  4. In all emergencies above 10,000 feet (Your Pressure must be
     released so emergency exits can be used).




OXYGEN SYSTEM

GENERAL:

    Your oxygen system is a low pressure demand system with 14 oxygen
stations corresponding to the various crew positions. The system
utilizes the same type of equipment described for the Heavy Bombers:

  1. A-14 Demand Mask (See Pg. 8-16).

  2. A-12 Demand Regulator (See Pg. 17-19).

  3. Pressure Indicator (Pg. 31).

  4. Flow Indicator (Pg. 31).

  5. Eighteen Type G-1 low pressure cylinders (Pg.37).

DISTRIBUTION:

    In the earlier B-29's, the oxygen cylinders were located in the
center wing section. At present, however, the cylinders are distributed
through the aft-portion of the ship. Regardless of the location of
cylinders, distribution is essentially the same. This distribution is
highly efficient. The entire loss of the O₂ supply to several crew
positions has been practically eliminated by the following principle.

  1. EACH OF THE FOURTEEN OXYGEN STATIONS IS SUPPLIED FROM TWO WIDELY
     SEPARATED DISTRIBUTION LINES DRAWING FROM AT LEAST TWO CYLINDERS
     EACH. LOSS OF ONE LINE OR ITS ASSOCIATED CYLINDERS STILL LEAVES
     EACH STATION WITH AN ALTERNATE SOURCE OF OXYGEN.

  2. The entire system is self-equalizing by use of cross feeds and
     automatic check valves. If part of the system is shot out, all
     functioning stations will have equal access to the remaining
     supply.

    Brief study of the diagram of the oxygen supply to a typical B-29
station (Fig. 15) will demonstrate the safety factors of this dual
source supply.

    Exact location of every oxygen cylinder and supply line may be found
in the late tech orders.

PORTABLE EQUIPMENT

Two types of walk-around bottles are furnished in the B-29:

  1. SEVEN D-2 TYPE WALK-AROUNDS (See Pg. 25, 26). ONE AT EACH OF
     FOLLOWING POSITIONS: PILOT, CO-PILOT, ENGINEER, NAVIGATOR, UPPER
     AND RIGHT GUNNERS AND RADAR OPERATOR.

  2. A-4 WALK-AROUND (See Pg. 24) One at each remaining station.

SERVICING:

    See Page 47 for servicing instructions. The filler valve is located
    on the left side of the fuselage.

[Illustration: Fig. 15]




EXPLOSIVE DECOMPRESSION

   With the use of pressurized compartments there is a possibility of
explosive decompression. This is most likely to occur if a blister is
blown either due to gunfire or a defective blister. Due to the excess
capacity of the superchargers, small cabin holes will not cause
explosive decompression. If explosive decompression occurred at 30,000
ft, the pressure altitude of the cabins would change from 8,000 ft to
30,000 ft in less than one second. What would happen in such a case?

PHYSICAL EFFECTS:

    The human body is affected very little by explosive decompression.
IF YOU GET OXYGEN YOU WILL SUFFER NO HARMFUL EFFECT. You may feel a
little distension of the belly or a little rush of air from the lungs,
but this is generally slight and of no consequence. Your ears should
clear automatically since you are going up, not down. The only dangers
of explosive decompression are as follows:

DANGERS:

  1. Tunnel -- During an explosive decompression a high velocity wind
     passes through the tunnel sufficiently strong to blow a man out the
     exits, and cause serious injury. The newer ships will have tunnel
     doors with small port hole openings; this will eliminate this
     danger. In ships not equipped in this fashion, NOBODY SHOULD ENTER
     THE TUNNEL WHEN THE SHIP IS PRESSURIZED.

  2. Blister -- ALWAYS FASTEN YOUR SAFTY BELT at the blister when the
     ship is pressurized. Otherwise you may be blown out of the ship
     by an explosive decompression. Also be certain that your mask is
     secured to your helmet, or it will be blown from the ship.

WHAT TO DO?

    The important thing in explosive decompression is to get oxygen
rapidly. To get oxygen rapidly you MUST at all times:

  1. Wear your helmet with the mask attached-let the mask hang from the
     helmet. Otherwise you may lose your mask and helmet.

  2. Keep the regulator hose clipped to your clothing and your mask
     plugged in.

    In case of explosive decompression, adjust your mask to the face and
fasten the hook on your helmet. You will then be O.K.

[Illustration: Fig. 16]




HIGH ALTITUDE BAIL-OUT

    If you must bail out above 20,000 feet, use the FREEFALL TECHNIQUE
described on page 23 except that you have an additional oxygen source
for bail out. Use the H-2 cylinder connected to your A-14 mask (Fig. 16)
as an oxygen supply DURING FREE FALL. Just before jumping, pull the rip
cord release on your H-2 cylinder. DO NOT OPEN YOUR CHUTE AT HIGH
ALTITUDE.




--REPRODUCED BY--

Reproduction Dept.

Army Air Field

Lincoln, Nebr.

10-18-44 20 M



[Transcriber's Notes:
  1. Original printed title
       NOTES ON THE USE OF OXYGEN EQUIPMENT
       IN THE B-17, B-24, & B-29 FOR COMAT CREWS
     was corrected to
       NOTES ON THE USE OF OXYGEN EQUIPMENT
       IN THE B-17, B-24, & B-29 FOR COMBAT CREWS
  2. In the text, phrases that were underlined for emphasis in the
     original are shown in this file with underscores surrounding
     the emphasized text, _like this_.
]