SYS - Environmental 2

Question 1

What engine bleed port used for pressurisation system?

Answer 1

P3

Question 2

What areas ensure the cockpit is pressurised sealed? (4)

Answer 2

• firewall
• AFT pressure bulkhead
• pressure flooring
• canopy pressure seal

Question 3

The __________ ___________ _____________ in the AFT pressure bulkhead monitors cockpit pressure and automatically adjusts the position of the ____________ ____________ __________.

Answer 3

Control valve regulator

Pressurisation control valve

Question 4

What altitudes is the cockpit pressure controlled to from sea level up to 31000ft?

Answer 4

From 8000ft cockpit PA it holds cockpit PA at 8000ft until 3.6 +/- 0.2 PSI at 18069 ft. then maintains this differential until 31000ft where a cockpit PA of 16600ft is experienced.

Question 5

What measures cockpit pressure differential?

Answer 5

Delta p regulator on aft pressure bulkhead

Question 6

When does safety valve open?

Answer 6

4.0 PSI

Question 7

When does the dump solenoid open the pressurisation control valve?

Answer 7

With weight on wheels

Question 8

Three positions of the pressurisation switch? And what do they do?

Answer 8

• norm
• dump (terminates power to dump solenoid opening pressurisation control valve. Fresh air valve remains closed and no ram air to cockpit)
• dump/ram (same as dump position but fresh air valve is opened. Defog valve automatically turned off)

Question 9

Will bleed air still flow into the cockpit when pressurisation switch in either dump or dump/ram?

Answer 9

Yes - unless BLEED AIR INFLOW switch is in off

Question 10

When does yellow CKPT ALT caution message appear?

Answer 10

> 19000 cockpit PA

Question 11

When does red CKPT PX appear?

Answer 11

3.9-40psid +/- 0.1

Question 12

What valve does the BLEED AIR INFLOW switch control?

Answer 12

Pneumatic system shutoff valve

Question 13

What two components does the Bleed air go through after the firewall before being hooked up to the anti-g suits?

Answer 13

• water separator

- safety valve (7psi)

Question 14

Basic operation of the anti g valve?

Answer 14

Weight rod and orifice

Question 15

What button is pressed to test the g suit?

Answer 15

HI FLOW

Question 16

Where does OBOGS get its bleed air from? Is it a separate port?

Answer 16

P3 left side, yes.

Question 17

How does the OBOGS system generate oxygen?

Answer 17

Extracts it from the conditioned engine Bleed air

Question 18

What two safety switches does OBOGS have?

Answer 18

• height temperature

- low pressure

Question 19

Where is OBOGS unit?

Answer 19

Fuselage right side avionics bay

Question 20

What does the concentrator do in the OBOGS unit do?

Answer 20

Automatically adjusts the oxygen pressure concentration for the current altitude based on current cockpit pressure

Question 21

What does the plenum function as between the OBOGS unit and the regulators?

Answer 21

Acts as a holding tank

Question 22

In event of OBOGS failure how much oxygen does the plenum provide?

Answer 22

Approximately on breath depending on cockpit pressurisation, aircraft PA, regulator settings and pilot demand.

Question 23

The occupy Ben pressure regulator supply lever controls? (2)

Answer 23

• system electrical power

- oxygen flow

Question 24

Which oxygen pressure regulator supply lever has priority?

Answer 24

If either is on, OBOGS is operative. Both must be off for the system to be off. Respective supply lever must be on to revive oxygen in each cockpit.

Question 25

Difference between max and normal on regulator concentration level?

Answer 25

• normal - OBOGS concentrator provides proper concentration for current cockpit PA
• max - max in either cockpit will provide highest concentration possible to both regulators. Also green maximum concentration light comes on.

Question 26

Difference between normal, emergency and test for regulator pressure level?

Answer 26

• normal - slight positive pressure
• emergency - positive pressure
• test - used to check face to face mask seal

Question 27

Purpose of anti suffocation valve and where is it?

Answer 27

Allows pilots to breath a,Brent cockpit air if OBOGS fails. Located where you connect oxygen hose into.

Question 28

What does OBOGS FAIL on EICAS mean?

Answer 28

Low pressure switch is closed because of low Bleed air pressure before the concentrator - such as prior to engine start or in event of loss of Bleed air

Question 29

OBOGS fail warning may occur because the mask is? (2)

Answer 29

Either loosely righted or down

Question 30

If OBOGS faile warning occurred because of a mask down, and fault doesn’t automatically clear after securing the mask, what can you do?

Answer 30

Perform and I-BIT test and if it passes then no further action.

Question 31

When does OBOGS TEMP appear?

Answer 31

When temp in OBOGS ducted exceeds 200deg f

Question 32

How long does automatic OBOGS built in test go for during OBOGS activation? How tell OBOGS fails the test?

Answer 32

3 minutes

OBOGS FAIL is inhibited for this time but appears after test if it has failed.

Question 33

How does OBOGS I-BIT work?

Answer 33

Opens a valve in the oxygen concentrator allowing ambient air into the system generating an OBOGS FAIL warning. When the valve closes the concentration returns to normal and the message disappears.

Question 34

Where is emergency oxygen cylinder located?

Answer 34

Left side of seat bucket

Question 35

What charge pressure is adequate for emergency oxygen cylinder?

Answer 35

1800-2500 PSI

Question 36

How activate emergency oxygen?

Answer 36

Green looped handle on left side of seat bucket?

Question 37

How long does emergency oxygen go for and can it be shut off?

Answer 37

10 minutes and can’t be shut off