Flight Crew Oxygen System
The flight crew oxygen system uses quick-donning, diluter-demand masks/regulators
located at each crew station. Oxygen is supplied by a single Oxygen pressure is displayed
on the Oxygen Pressure indicator located overhead panel when the battery switch is ON.
Oxygen flow is controlled an in-line, pressure-reducing regulator to supply low-pressure
oxygen regulator on the mask. Minimum pressure for dispatch is variable by temperature
and additional flight deck crew.
System pressure may be as high as 1850 psi.
Passenger Oxygen System
The passenger oxygen system is supplied by individual chemical oxygen generators
located at each Passenger Service Unit (PSU). Four continuous flow masks are connected
to each generator. A generator with two masks is located above each attendant station and
in each lavatory.
The system is activated automatically by a pressure switch at a cabin altitude of
approximately 14,000 feet or when the Passenger Oxygen Switch on the aft overhead panel
is positioned to ON. When the system is activated, the PASS OXY ON light illuminates and
OVERHEAD illuminates on the Master Caution System.
When the optional High Altitude Landing Switch [Option], located on the Cabin Altitude
Panel, is placed in the ON position the cabin altitude warning horn is reprogrammed from
10,000 feet to 14,000 feet and automatic oxygen mask activation is reprogrammed to
14,650 feet.
