737 MAX Flight Crew Operations Manual
Airplane General, Emergency
Equipment, Doors, Windows -
Systems Description
MN-FLT-OH-201
1.40.19
The system is activated automatically by a pressure switch at a cabin altitude of
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.
1B401, 1B402, 1B801 - 1B824
Activating the system causes the masks to drop from the stowage compartments.
The oxygen source is activated when any mask in the unit is pulled down. Pulling
one mask down causes all masks in that unit to come down and 100% oxygen
flows to all masks. A green in–line flow indicator is visible in the transparent
oxygen hose whenever oxygen is flowing to the mask. Oxygen flows for
approximately 12 minutes (22 minutes as installed) and cannot be shut off. If the
passenger oxygen is activated and a PSU oxygen mask compartment does not
open, the masks may be dropped manually.
PSU Oxygen Mask Compartment
WARNING: When using passenger oxygen, the “NO SMOKING” sign
should be strictly observed. Once the oxygen source is
activated, the flow of oxygen is constant, whether or not the
mask is being worn.
WARNING: Do not use passenger oxygen with cabin altitude below 14,000
feet when smoke or an abnormal heat source is present. The
use of passenger oxygen does not prevent the passengers from
inhaling smoke. Air inhaled is a mixture of oxygen and cabin
air.
DOOR LATCH
MECHANISM
OXYGEN IN-LINE
OXYGEN SOURCE
OXYGEN MASK LANYARD
PSU
OXYGEN MASK DOOR
(SHOWN OPEN)
RESERVOIR BAG
MASK
FWD
RELEASE FIRING PIN
LANYARD
OXYGEN HOSE
FLOW INDICATOR
March 1, 2021
