TM 1-1510-224-10
NOTE
Check to ensure that the OXYGEN
SUPPLY PRESSURE gage registers
adequate pressure before each flight.
When oxygen is in use, a check of
the supply pressure should be made
at intervals during flight, to note the
quantity available and to approximate
the
supply
duration.
Outside
temperature is reduced as altitude is
increased. Oxygen cylinders thus
cooled by temperature change will
show a pressure drop. This type of
drop in pressure will rise again upon
return to a lower or warmer altitude.
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 likely. Whenever oxygen is
inhaled, a blinkervane slides into view within the flow
indicator window, showing that oxygen is being released.
When oxygen is exhaled, the blinker vane vanishes from
view.
c.
Oxygen masks.
WARNING
Pure
oxygen
will
support
combustion. Do not smoke while
oxygen is in use.
Oxygen masks for the pilot and copilot are provided.
To connect a mask into the oxygen system, connect the
line attached to the mask to the flexible hose which is
attached to the cockpit sidewall. The microphone in the
oxygen mask is connected to the audio system through
the pilot's or copilot's headset/oxygen mask microphone
selector switch, located on the instrument panel
(fig. 2-18). To test mask and hose integrity, place the
supply control lever on the regulator control panel to the
ON position, put on and adjusts the mask, select TEST
MASK position, and check for leaks.
If any symptoms occur suggestive of the onset of
hypoxia, immediately set the emergency pressure
control lever to the EMERGENCY position and descend
below 10,000 feet. Whenever carbon monoxide or other
noxious gas is present or suspected, set the diluter
control lever to 100% oxygen and continue breathing
oxygen until the danger is past.
d.
Normal
Operation.
Oxygen
pressure
is
maintained at all times to the regulator control panels if
the cylinder shut-off valves are open and if there is
pressure in the cylinders. Each individual places the
supply lever (green) on the regulator control panel to the
ON position, and the diluter lever (white) to the
NORMAL OXYGEN position.
e.
Emergency
Operation.
For
emergency
operation, the affected crew member selects the
EMERGENCY
Table 2-5. Oxygen Duration In Minutes 140 Cubic Foot System
CABIN
PRESSURE
ALTITUDE
CREW
MASK
CONDITION
TOTAL
FLOW
LPM-NTPD
DURATION
IN
MINUTES (1)
TWO MAN
CREW
35,000
31,000
25.000
20,000
20,000
15,000
15,000
10,000
10,000
100%
100%
100%
100%
NORMAL
100%
NORMAL
100%
NORMAL
6.3
8.4
11.8
15.2
7.2
19.0
10.2
23.8
13.8
512.1
384.0
273.3
212.2
448.0
169.7
316.2
135.5
233.7
TWO MAN
CREW PLUS
ONE PASS
35,000
31,000
25,000
20,000
20,000
15,000
15,000
10,000
10,000
100%
100%
100%
100%
NORMAL
100%
NORMAL
100%
NORMAL
10.0
12.1
15.5
18.9
10.9
22.7
13.9
27.5
17.5
323
266.6
208.1
170.7
295.9
142.1
232.1
117.3
184.3
(1) For 100% capacity of usable oxygen, 3,226 L.
BT00197
2-64
