MD-11 Flight Crew Operations Manual
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Emergency Equipment -
Description and Operation
Emer.10.2
The toggle valve on the regulator allows selection of 100 percent oxygen or a
normal diluter demand breathing schedule.
The EMERGENCY pressure control knob provides a regulator flow test, and a
positive pressure flow to the mask under emergency conditions (high cabin
altitudes, smoke in the cabin). This allows only pure oxygen to flow to the mask.
The pneumatic harness is inflated for donning or doffing the mask by manually
actuating a lever on the regulator. The harness will deflate upon release of the
lever.
Each mask and smoke goggle assembly is stowed in a quick access stowage box
at each flight crew station. The oxygen supply lines and microphone connections
are at the base of each stowage box. The oxygen stowage box consists of:
• Supply manifold and check valve.
• PRESS TO TEST AND RESET lever.
• Flow indication blinker.
• Oxygen on flag.
• Mask supply hose with a quick disconnect fitting.
The crew oxygen system line pressure is sensed by a transducer located in the
supply line leading to the First Officer's oxygen mask stowage box. The line
pressure indicator is the same one used to indicate the crew cylinder quantity and
is controlled by a switch near the indicator. One switch position will display
cylinder quantity and the other position will display line pressure on the indicator.
The overboard relief indicator for both the cylinder shutoff valve and the regulator
supply line overpressure are plumbed together to a single line which leads to the
green blowout disc.
Passenger Oxygen
The passenger oxygen system provides emergency supplemental oxygen for all
cabin occupants in the event of cabin depressurization. Oxygen masks are
available:
• In the lavatory(s).
• At the attendant stations.
• At all installed passenger seats.
If the cabin altitude goes above 14,400 feet, a signal will be sent to open the
oxygen mask doors. If the doors are not commanded open by 14,770 feet, the NO
MASKS switch on the forward overhead panel will illuminate.
The same logic is used by the EIS for the NO MASKS alert on the EAD. The crew
will then push the NO MASKS switch for 3 to 5 seconds. This action will deploy
the masks through both relays. Pushing the NO MASKS switch will also
extinguish the NO MASKS light and the alert.
October 02, 2006
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