Mod : 4292
ATR 42 Model : 400/500
OXYGEN SYSTEM
EMERGENCY EQUIPMENT
P 1
NOV 98
100
1.07
.
20
20.1 DESCRIPTION
(See schematic p 7/8)
The system consists of a main system supplying the cockpit crew and the passengers
and one portable unit for the cabin attendant.
A high pressure cylinder of 3310 l (115 cu.ft) capacity, supplies oxygen to the
distribution system. Nominal charge pressure of 1850 PSI is reduced to 78 PSI in the
distribution system. A discharge part is provided to face overpressures.
CREW MEMBERS
(See schematic p 9/10)
The quick donning masks are stowed in readily accessible containers adjacent to
each crew member seat. The mask harness inflates automatically when the mask is
pulled out of the container and it can easily be donned with one hand. A mask
mounted diluter demand regulator provides dilution and emergency pressure control :
- In case of pressure drop, with the dilution control in the N (normal) position, diluted
oxygen is provided to 2 pilots and 1 observer for a duration of 120 mn at demand flow
(10 minutes to descend from 25 000 ft to 13 000 ft and continuation of flight
between 13 000 ft and 10 000 ft for 110 minutes).
- In case of smoke or noxious gas emission, xith the dilution control in the 100 %
position, oxygen is provided to 2 pilots and 1 observer for a duration of 15 minutes at
demand flow.
CABIN ATTENDANT PORTABLE UNITS
- One 120 l (4.25 cu ft) portable oxygen bottle is stowed under the cabin attendant
seat. It permits a continuous diluted flow to cabin attendant at 13 000 ft for a duration
of 30 mn. The bottle is equipped with a diluted oxygen mask.
- Protective breathing equipments are located in the baggage box of the cabin.
- The cabin attendant station is equiped with automatic oxygen masks boxes.
PASSENGERS
The main system provides passenger protection through a PAX SUPPLY valve. It
controls flow to oxygen masks installed in the cabin under the hat racks and in the
toilets. They are stored into mask boxes with automatic opening.
Oxygen system capability allows to supply 100 % of the passengers with a continuous
diluted flow for a duration of 30 mn in case of pressure drop (4 minutes to descend
from 25 000 ft to 13 000 ft, 26 minutes to continue the flight between 13 000 ft and
10 000 ft) in addition to the cockpit crew 120 minutes consumption.
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01/07//2018 REV 1 These notes are not revised after issue For Training Purposes Only
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