Learjet 20 Series Pilot Training Manual page 343

OXYGEN PRESSURE GAGE
The OXYGEN PRESSURE gage (Figure 17-5)
provides a direct reading of oxygen cylinder
pressure, which is necessary to ensure that an
adequate supply of oxygen is aboard. The gage,
located at the top of the copilot's instrument
panel, is marked as follows:
• Yellow arc ............................. 0–300 psi
• Green arc .....................1,550 –1,850 psi
• Red line .................................. 2,000 psi
Figure 17-5. OXYGEN PRESSURE Gage
CREW DISTRIBUTION SYSTEM
The crew distribution system (see Figures 17-1
through 17-3) consists of the pilot's and copilot's
oxygen masks with mask-mounted regulators for
diluter-demand or 100% operation. Oxygen is
available to the crew any time the storage bottle
shutoff valve is open and the masks are plugged in.
17-6
LEARJET 20 SERIES PILOT TRAINING MANUAL
FOR TRAINING PURPOSES ONLY
The crew masks (Figure 17-6) are stowed on the
pilot's and copilot's sidewalls. The mask oxygen
lines are connected to quick-disconnect
receptacles located on the cockpit sidewalls.
Optional oxygen-flow detectors may be installed
in the mask oxygen lines.
NOTE
Headsets, eyeglasses, or hats worn by
crewmembers may interfere with the
quick-donning capabilities of the
oxygen mask.
Figure 17-6. Crew Oxygen Mask
On 24E/F-350 and subsequent and 25D-227 and
subsequent, crew masks are pressure demand
with normal, 100%, and pressure positions that
can be selected by the crew.
NOTE
Use oxygen if pressurization irregu-
larities are encountered in flights
above 10,000 feet.
Following are descriptions of three oxygen
masks/regulators commonly used on Lear 20
aircraft. Consult the applicable AFM for
specifics on mask/regulator operation and
oxygen duration charts.
The ZMR 100 diluter-demand mask regulator
has a NORMAL–100% oxygen selector lever.
With NORMAL selected, the regulator delivers
diluted oxygen, on demand, up to 20,000 feet
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