Pneumatics And Air Conditioning

Question 1

How many bleed sources are there per engine?

Answer 1

2 (NL and NH)

Question 2

When does Nh bleed air help to supply the pnuematic system?

Answer 2

when pnuematic pressure is below 55PSI in the air or below 65PSI on the ground

Question 3

When does the 18PSI system recieve pressure

Answer 3

when the engine is on

Question 4

BLEED HOT

Answer 4

bleed air exceeds 287 deg. valves auto close

Question 5

If one bleed valve is closed, will pressurisation be affected?

Answer 5

No

Question 6

What do the air conditioning packs provide?

Answer 6

conditioned air to the cabin and flight deck, air for pressurisation

Question 7

If one air con pack is off will pressurisation be affected?

Answer 7

No

Question 8

How many air con packs are there?

Answer 8

2

Question 9

If both packs are off will pressurisation be affected?

Answer 9

Yes - no bleed air in

Question 10

CABIN PACK HOT

Answer 10

1 pack air cycle machine exceeds 207deg or 75psi. Auto shutoff/valve close

Question 11

FLT COMP PACK HOT

Answer 11

2 pack air cycle machine internal temp 207deg or 75psi. Auto valve shutoff

Question 12

How is the Air conditioning system controlled in manual mode?

Answer 12

with the cold/hot toggles

Question 13

How many outflow valves are there?

Answer 13

3 (2 AUTO rear, 1 manual front)

Question 14

How are the rear outflow valves opened and closed?

Answer 14

using 18PSI against a spring, controlled by the pressure controller unit

Question 15

What happens if the aircraft lands pressurised?

Answer 15

the cabin will climb at 600ft/min for 1min then dump (with less than 2.5PSI diff)

Question 16

What is needed for DUMP valve switch to operate in the air?

Answer 16

switch needs to be powered, 18PSI air.

Question 17

Normal max cabin pressure diff?

Answer 17

5.5PSI +-0.3

Question 18

Max cabin diff (pressure relief valve)

Answer 18

5.95PSI

Question 19

What does the manual knob do?

Answer 19

changes the forward outflow valve to alter cabin alt

Question 20

What does the manual switch on the f/o side panel do?

Answer 20

fully opens the forward outflow valve (DUMP)

Question 21

what are the 4 main modes of the pressurisation system?

Answer 21

AUTO, MAN, DUMP, CAB SET

Question 22

Max cabin alt?

Answer 22

8000ft

Question 23

How would you manually set a lower cabin alt?

Answer 23

Semi auto(cab set) - set desired cabin altitude (unpressurised at that level when on descent)

Question 24

What is the cabin rate of climb and descent at the detent?

Answer 24

500ft/min climb, 300ft/min descent

Question 25

What does the fault light mean on the pressure controller mean?

Answer 25

Pressure controller has failed. Rear valves fully shut

Question 26

what will happen to cabin altitude if pressure controller fails?

Answer 26

cabin altitude will rapidly decrease until max diff is reached, and stay at 5.95psi.

Question 27

CABIN PRESS

Answer 27

Cabin altitude exceeded 10000ft. Emergency descent to 10k or MSA.

Question 28

Memory items EMERG descent?

Answer 28

Oxy Mask on Mic switch mask, pax signs on emerg descent, accomplish A/req (P/L FI, C/L max, maintain Vmo)

Question 29

In an electric failure, what positions do the compressor bleed valves default to?

Answer 29

NL open | NH closed

Question 30

Which pack is selected when bleed set to MIN

Answer 30

Pack 2

Question 31

DUCT HOT

Answer 31

outlet of a pack is over 88deg. Auto to full cold.

Question 32

Where are the temp sensors for cabin temp?

Answer 32

by the CAPT feet, under 5A, At the outlet ducts

Question 33

Which pack(s) work with the APU on?

Answer 33

Both when set to NORM

Question 34

Why do we need to turn the APU bleed air off before opening engine bleeds?

Answer 34

There's no one way valve so the pressure will cause APU to stall/surge

Question 35

What bus is the Pressure controller connected to

Answer 35

L MAIN

Question 36

Which valve(s) have the 5.95PSI regulator?

Answer 36

All 3

Question 37

If you switch to manual pressurisation and the manual knob is fully anti-clockwise, what should you do first?

Answer 37

Bleed to MIN or off first (stops large drop in cab alt)

Question 38

Will a pressure controller fault bring on the Master caution?

Answer 38

No

Question 39

What is the Cabin PSI max on the ground?

Answer 39

0.5PSI