Oxygen supply pressure gage.
The 500 PSI oxygen pressure gage
provided on the oxygen control
panels should never indicate over
400 PSI. If the pressure exceeds
400 PSI, a malfunction of the
pressure reducer is indicated.
Whenever oxygen is inhaled, a blinker-vane
slides into view within the flow indicator window, showing
that oxygen is being released. When oxygen is exhaled,
the blinker vane vanishes from view.
Check to insure that the OXYGEN
SUPPLY PRESSURE gage registers
adequate pressure before each
flight. When oxygen is in use, a
should be made at intervals during
flight to note the quantity available
and to approximate the supply
duration. The outside temperature
is reduced as an aircraft ascends to
higher altitudes. Oxygen cylinders
thus cooled by temperature change
will show a pressure drop. This
type of drop in pressure will raise
again upon return to a lower or
warmer altitude. A valid cause for
alarm would be the rapid loss of
oxygen pressure when the aircraft
is in level flight or descending;
descend as rapidly as possible to
altitude which does not require the
use of oxygen.
combustion. Do not smoke while
oxygen is in use.
If any symptoms occur suggestive
immediately set the emergency
EMERGENCY position and descend
carbon monoxide or other noxious
gas is present or suspected, set the
OXYGEN and continue breathing
undiluted oxygen until the danger
Oxygen Masks. Oxygen masks for the pilot and
copilot are provided as personal equipment. To connect a
mask into the oxygen system, the individual connects the
line attached to the mask to the flexible hose which is
attached to the cockpit sidewall. The microphone in the
oxygen mask is provided with a cord for connecting with
the helmet microphone jack. To test mask and hose
integrity, the individual places the supply control lever on
the regulator control panel to the ON position, puts on and
adjusts his mask, selects TEST MASK position, and
checks for leaks.
maintained at all times to the regulator control panels if
the cylinder shut-off valves are on and if there is pressure
in the cylinders. Each individual places the supply lever
(green) on his regulator control panel to the ON position,
and the diluter lever (white) to the NORMAL OXYGEN
Emergency Operation. For emergency operation,
the affected crew member selects the EMERGENCY
position of the emergency pressure control lever (red) on
his regulator control panel. This selection provides 100%
oxygen at a positive pressure, regardless of the position
of the diluter control lever on his panel.
f First Aid Operation. A first aid oxygen mask is
installed in the aft cabin area as a supplemental or
emergency source of oxygen. The mask is stowed behind
an overhead cover placarded FIRST AID OXYGEN PULL.
Removing the cover allows the mask to drop out of the
container, exposing a manual control valve, which
releases oxygen to the mask when placed in the ON
position. After using the mask, the manual valve in the
container must be turned OFF before stowing the mask
and replacing the cover.
Oxygen Duration Example Problem.
Duration in minutes of oxygen
at 100% capacity.
Two man crew plus one passen-
ger, cabin pressure altitude =
15,000 feet, crew masks, normal,
Find "two man crew plus one
pass" line, move right then down
to 15,000 - "normal" read "232.
Duration of oxygen for previous
example data at 84% of capacity.
232.1 minutes duration at 100%,
84% capacity, total aircraft flow
= 13.9 LPM.