Oxygen

Question 1

How many oxygen cylinders

Answer 1

The flight crew and passenger oxygen system supplies oxygen to the flight crew and passengers during cabin depressurization, smoke contamination, or other emergencies. The flight crew and passenger oxygen system consists of four storage cylinders each with a regulator, pressure switch and check valve. The system also includes a pressure transducer, a passenger oxygen control panel (altimetric valve), oxygen masks and stowage boxes, overboard discharge indicator and ground service panel. Four storage cylinders supply oxygen to the flight crew and passengers. The oxygen is available to the crew through quick-donning, pressure demandtype face masks, with mask-mounted regulators. Passenger oxygen masks are installed within oxygen drop boxes. The passenger control panel, in the flight compartment right side console, controls automatic and manual deployment of the passenger oxygen masks, and the availability of oxygen to the masks. Therapeutic oxygen supply is also available by selection from the control panel. The pressure transducer and switches monitor the oxygen system pressures and provide information to EICAS.

Question 2

Is it fully automated

Answer 2

Yes, knows what altitude, via o2 control panel

Question 3

Is o2 displayed on EICAS

Answer 3

Yes and synoptic, EICAS status page

Question 4

Pax select should be on Normal

Answer 4

Yes called Altimetric valve rotary selector

Question 5

Where is o2 panel

Answer 5

F/o,s side panel

Question 6

Min o2 for dispatch

Answer 6

75 percent on EICAS, temp compensated by volume

Question 7

How many cylinders

Answer 7

Four storage cylinders supply the crew and passenger oxygen system. The storage cylinders are installed below the flight compartment floor on the left and right sides. The cylinders are filled through a ground servicing panel at the nose of the aircraft on the left side. Each cylinder has a volume of 50.1 cubic feet (1418 liters) and are charged to a nominal 1850-psi pressure. Each storage cylinder has a direct reading pressure gauge to indicate oxygen pressure in the cylinder. The storage cylinders have a service life of 15 years, and require hydrostatic testing every 36 months.

Question 8

What happens with over pressure

Answer 8

Four storage cylinders supply the crew and passenger oxygen system. The storage cylinders are installed below the flight compartment floor on the left and right sides. The cylinders are filled through a ground servicing panel at the nose of the aircraft on the left side. Each cylinder has a volume of 50.1 cubic feet (1418 liters) and are charged to a nominal 1850-psi pressure. Each storage cylinder has a direct reading pressure gauge to indicate oxygen pressure in the cylinder. The storage cylinders have a service life of 15 years, and require hydrostatic testing every 36 months.

Question 9

With oxygen flowing what happenss to power

Answer 9

Cabin power is automatically switched off

Question 10

What is altimetric valve

Answer 10

Oxygen supply to the passengers is controlled automatically or manually by the passenger oxygen control panel located in the copilot side console. The passenger oxygen control panel includes a three-position rotary selector with CLOSED, NORMAL and OVERRIDE positions, a TEST PORT plug and a THERAPEUTIC OXYGEN pushbutton annunciator (PBA).

Question 11

What happens above 1800ft

Answer 11

Cabin auto supply

Question 12

What is minimum bottle press

Answer 12

A placard at the fill panel indicates the proper fill pressure based on OAT. The maximum fill rate is 200 psig/min. The minimum bottle pressure is 50 psig, bottle purging is required if pressure in the storage cylinder falls below this limit.

Question 13

Past ident on normal valve what happens

Answer 13

O2 masks will deploy

Question 14

How many therapeutic o2 outlets

Answer 14

3

Question 15

Discharge indicator

Answer 15

Green disc, 2600psi +- 100 psi

Question 16

What press is flight crew

Answer 16

Oxygen pressure is supplied to the flight crew masks from the storage cylinders by the pressure regulator at 70-psi pressure. Oxygen flow is available in three modes to each mask and is controlled by the flow regulator.

Question 17

What modes are o2 supply

Answer 17

FLIGHT CREW AND PASSENGER OXYGEN SYSTEM
placed over the head. When the plate is released, the elastic harness shrinks providing a snug fit. Oxygen pressure is supplied to the flight crew masks from the storage cylinders by the pressure regulator at 70-psi pressure. Oxygen flow is available in three modes to each mask and is controlled by the flow regulator.
Normal Mode N (normal) automatically supplies a mixture of ambient air and oxygen (diluted). Flow is upon demand. 100% Mode 100% pure oxygen is available by sliding the switch down to the 100% position. This mode is generally used in case of smoke or toxic fumes in the cockpit. Flow is upon demand.

Emergency Mode Emergency is obtained with the N-100% switch in “100%” and by depressing and rotating the PRESS-TO-TEST button to the EMERGENCY position. This mode is used at high altitude to aid breathing. N and 100% modes are “on demand” meaning that oxygen is available only by operator breathing.
In the EMERGENCY mode, a constant flow is available at slightly higher pressure. Each mask includes an oxygen supply hose, and an oral-nasal mask shell with an inflatable harness. A microphone and microphone leads are also incorporated in the mask assembly. The mask stowage boxes are located in the side consoles of the pilot and copilot. They incorporate a door-operated shutoff valve, a flow indication blinker, and a reset/test switch.

Question 18

What is altimetric valve

Answer 18

Initial press 70psi purge for 5 secs

(Altimetric Valve) Operation Figure 8 With the three-position rotary selector in the
NORMAL position, the altimetric valve will operate automatically. If a cabin depressurization occurs, oxygen will be supplied to the passengers mask boxes as described below: Automatic sequence (NORMAL position): • If a cabin altitude climbs and reaches 14,500 ft- Lever A, differential valve A and differential valve B opens- Outlet pressure: 70 psig for 5 seconds to open passenger mask boxes- After 5 seconds, differential valve B closes and pressure reducer adjusts pressure at passenger masks to 22 psig • If cabin altitude then reaches 21,000 ft- Lever B and differential valve B opens- Outlet pressure increased to 70 psig at passenger masks • When cabin altitude descends to 18,000 ft- Lever B and differential valve B closes- Outlet pressure decreased again to 22 psig at passenger masks • When cabin altitude descends to 10,000 ft or lower- Lever A and differential valve A close- Flow to passenger masks stop The flight crew may take priority over the automatic (NORMAL) mode by moving the threeposition rotary selector to the OVERRIDE position. This will start the oxygen flow to the passenger mask boxes.

Question 19

What is pax o2 system interface

Answer 19

Passenger Oxygen System Interface Figure 9
The oxygen pressure transducer monitors the crew oxygen-system pressure. The analog signal is provided to the DAU. The transducers pressure is displayed as a percentage readout corresponding to oxygen capacity indicated on the status page.
The EICAS will set a CAS message at or below 75% (OXYGEN LO QTY). The oxygen pressure switches monitor the four oxygen storage cylinders outlet line pressure. A discrete signal is received by the DAU indicating pressure is available to the system from the storage cylinder. EICAS will provide an indication if one or more of the oxygen storage-cylinder regulatorlevers is left in the OFF position (OXYGEN LO QTY).
Two pressure switches in the passenger oxygen delivery lines indicate that the altimetric valve or the therapeutic valve is delivering oxygen flow to the passenger system. The passenger oxygen line pressure switch discrete signal is received by the DAU.
EICAS will set a CAS message (PASSENGER OXY ON) when a switch indicates oxygen is flowing. The therapeutic oxygen pressure switch will cause the therapeutic PBA ON light to illuminate in the case of the therapeutic systems activation.