Specifications

SECTION II
AIRPLANE AND SYSTEMS
MODEL 560
CREW OXYGEN MASKS
The EROS crew mask is a quick donning diluter-demand/pressure breathing mask with integral
microphone and oxygen regulator. It is certified to a maximum cabin altitude of 40,000 feet.
A red rocker lever on the bottom of the mask labeled "N" and "100%" selects either NORMAL or
100% oxygen scheduling to the mask. In NORMAL mode the regulator increases the proportion of oxygen
mixing with the cabin air as cabin altitude increases. Above approximately 27,000 feet cabin altitude
NORMAL mode provides 100% oxygen. The "100%" position provides 100% oxygen at all cabin altitudes
To provide the quickest recovery from hypoxia symptoms, the mask should be stowed with the 100%
selected. To conserve oxygen, in the absence of smoke/fumes the mask should be switched to NORMAL
when worn at any cabin altitude for an extended period of time.
Depressing a red tab on the front of the mask (left side, as viewed while wearing the mask) inflates
the harness for donning. Releasing the tab causes the harness to conform to the user's head. To prevent
damage to the harness it should not be inflated until the mask is completely out of the storage box.
The mask automatically supplies oxygen under pressure (pressure breathing) beginning at
approximately 35,000 feet cabin altitude. Automatic pressure breathing is available in either NORMAL or
100% mode. Once pressure breathing begins, pressure supplied to the mask gradually increases as cabin
altitude increases. Ability to speak via the mask microphone is not significantly impaired during pressure
breathing.
A red knob on the bottom of the mask labeled EMERGENCY provides 100% oxygen flow and creates
a positive oxygen pressure in the mask. Turning the knob approximately one quarter turn in the direction of
the arrow selects EMERGENCY mode. Pressing the knob "in" momentarily may be used for mask preflight
to ensure flow to the mask. Continuous EMERGENCY mode must be used in a smoke/fume environment
to provide positive pressure to the mask and goggles. One the need for emergency pressure has been
alleviated, EMERGENCY mode should be deselected as the oxygen consumption rate is high.
Smoke goggles (if provided with the EROS mask) are designed to fit over the mask and interface with
a vent on the outside of the mask nose-bridge area. In a smoke/fumes environment, the mask should be
donned first, then the goggles. A gray plastic slide on the mask nose bridge may then be pulled downward,
opening the goggle vent. In the vent is fully open when a red band is visible above the slide. The upper
harness tubes should be placed over the goggle frame's lower sides to provide maximum sealing. When
smoke/fumes have been eliminated, the mask should be switched out of EMERGENCY mode and the nose
bridge valve closed.
A two-position toggle switch is provided on the pilot's and copilot's side consoles. The switch is
marked MIC OXY MASK and MIC HEAD SET. Depressing the microphone button on the appropriate
control wheel allows a crewmember to transmit through the headset microphone or oxygen mask
microphone, whichever is selected.
Oxygen pressure to the mask may be verified by setting the microphone switch to MIC OXY MASK,
and keying the ICS MIC while selecting EMER position on the mask. Verify oxygen flow and listen for the
sound of the flow through the headset or speaker to verify the oxygen mask microphone.
NOTE
Crew masks are assumed to be in the NORMAL setting below 25,000 feet cabin
altitude and at 100% setting at or above 25,000 feet.
I 2-60 Configuration AA 56OMB-01