skyblue CBT air con and pressurisation

Question 1

where are the 2 packs located?

Answer 1

in the gear bays

Question 2

where is the external air plug located?

Answer 2

right hand side of aircraft

Question 3

what does the left duct supply?

Answer 3

flight deck and pax cabin

Question 4

what does the right duct aupply?

Answer 4

pax cabin

Question 5

can one pack supply both compartments?

Answer 5

yes, through the mixing chamber

Question 6

what conditions bleed air after the pack valve?

Answer 6

air cycle machine (one on each side of the aircraft

Question 7

where does conditioned air go after the air cycle machine?

Answer 7

the mixing chamber under the flor of the aircraft to be mixed with ambient air

Question 8

how is air evacuated from the cabin and where does it go?

Answer 8

guides along left floor of the cabin

recircualted to the cabin or exhausted through outflow valves under the aft fuselage

Question 9

how is the toilet ventilated?

Answer 9

a vent line regulated by cabin differential pressure

Question 10

how is pressurisation regulated?

Answer 10

by constricting the amount of air vented overboard by opening and closing outflow valves under the aft fuselage

Question 11

how are the pack valves controlled and operated?

Answer 11

electrically controlled and pneumatically operated

Question 12

what is the purpose of the pack valves?

Answer 12

shut down the pack and maintain a constant air supply pressure to the pack

Question 13

what powers both pack valves?

Answer 13

DC ESS BUS

Question 14

what pressure will the pack valves deliver to the packs with the flow button out?

Answer 14

22psi

Question 15

what pressure will the pack valves deliver to the packs with the button pressed in? (hi flow)

Answer 15

30psi

Question 16

where is the primary heat exchanger located?

Answer 16

landing gear fairing

Question 17

where does air flow after the pack valve?

Answer 17

heat exchanger

Question 18

what does the ground cooling fan do?

Answer 18

blows air over the heat exchanger if ram air is insuffcient

Question 19

how is the ground cooling fan powered?

Answer 19

pneumatic air through an impeller controlled by the turbofan shutoff valve

Question 20

when does the turbofan shutoff valve open?

Answer 20

airspeed less than 150knots

gear extended or retracted for less than 10 mins

Question 21

when is the turbofan shutoff valve closed?

Answer 21

anytime the airspeed is greater than 150 knots

Question 22

what will the turbofan shutoff valve do if opposite low oil pressure is sensed?

Answer 22

open as long as speed is 150 or less

Question 23

what will the pack valve do if the turbo fan shutoff valve is not in the commanded position?

Answer 23

close to prevent pack damage

Question 24

where does air flow after the heat exchanger?

Answer 24

compressor, secondary heat exchanger

Question 25

where does air for the heat exchangers come from?

Answer 25

ram air flow

Question 26

where is air from the secondary heat exchanger sent?

Answer 26

used to power the turbine

Question 27

what does air do once it reaches the turbine section?

Answer 27

undergoes rapid expansion which decreases temp

Question 28

what controls airflow into the turbine?

Answer 28

turbine inlet control valve

Question 29

where does air flow to from the turbine?

Answer 29

a condenser and then a mixing chamber

Question 30

how does the condensor dry the air?

Answer 30

uses air from the primary heat exchanger to send air to the water extractor, then back through the turbine and to the mixing chamber

Question 31

how is temperature control acheived?

Answer 31

mixing bleed air tapped downstream of the pack valve and air produced by expansion turbine

Question 32

what controls how much bleed air is used wih regard to temperature control?

Answer 32

temperature controller set by electronic controller or the rotary knob in the flight deck

Question 33

what information does the electronic temperature controller use to determine temperature whe set to auto?

Answer 33

1. compartment ambient temperature 2. aircraft skin temperature 3. pack supply duct temperature

Question 34

what is temperature limited to by the pack duct in manual mode?

Answer 34

88C

Question 35

what temperature will trigger the AIR DUCT OVHT?

Answer 35

92C

Question 36

at what temperature will the pack valve close if the overheat is downstream of the compressor?

Answer 36

204C

Question 37

what does the mixing chamber mix?

Answer 37

air produced by air from pack and ambient cabin air

Question 38

how is cabin air evacuated?

Answer 38

2 recirculation fans which send air back to the mixing chamber

Question 39

what powers the recirculation fans?

Answer 39

DC UTIL BUS

Question 40

when will the recirculation fans automatically run at full speed?

Answer 40

when cabin floor temp is less than 18C

Question 41

what will cause a AIR RECIRC FAN caution?

Answer 41

fan speed too low associated electric motor overheats

Question 42

what parts of the plane are ventilated by ambient air?

Answer 42

flight deck forward cargo compartment electronic racks

Question 43

where is ambient air from the flight deck, electric racks and forward cargo compartment sent?

Answer 43

pressurised compartment or overboard

Question 44

what does the ventilation extract fan do?

Answer 44

draws air into the forward compartment to cool flight deck, electric racks and flight instruments

Question 45

what speed will the extract fan operate at if flight deck temp is below 20 degrees?

Answer 45

low

Question 46

what speed will the flight deck fan operate at if flight deck temperature is above 52 degrees?

Answer 46

high

Question 47

why would we use the extract air flow lever?

Answer 47

to stop air from flowing forward if smoke is detected in forward cargo compartment

Question 48

how long will the extract fan stop for during start to avoid pressure shocKS?

Answer 48

120 seconds

Question 49

what does the overboard valve do?

Answer 49

allows air from the extract valve to be sent overboard

Question 50

on the ground with engine 1 or has low oil pressure what will the overboard valve do?

Answer 50

it will be open. extract fan will run normally. underfloor will be closed

Question 51

what will the extract fan do in flight or with engine 1 running on the ground?

Answer 51

underfloor valve open overboard valve closed

Question 52

what controls air outflow for pressurisation?

Answer 52

1 pneumatic outflow 1 electro pneumatic outflow

Question 53

what happens with the pressurisation system in auto mode?

Answer 53

pneumatic outflow valve is slaved to the electro pneumatic outflow valve which allows them to operate simultaneously

Question 54

when will the outflow valve protection activate through the manometric capsules?

Answer 54

positive differential pressure greater than 6.35psi negative 0.5psi

Question 55

what powers the pressurisation digital controller?

Answer 55

DC BUS 1

Question 56

how does the digital controller position the outflow valves?

Answer 56

a torque motor

Question 57

what 4 parameters does the digital controller use to calculate required cabin pressure?

Answer 57

1. departure field elevation 2. destination field elevation 3. existing cabin altitude 4. aircraft altitude (baro if ADC 1 STD if ADC 2)

Question 58

which valve is used in manual pressurisaton mode?

Answer 58

pneumatic only

Question 59

what ROC/ROD can be set in manual mode?

Answer 59

-1500 to +2500rpm

Question 60

what does setting the pressure knob to 9-10 o clock ensure when switching to manual mode from automatic?

Answer 60

ensures no pressure bump at the switch over

Question 61

what signal does the landing gear microswitch give to the pressurisation digital controller?

Answer 61

determines how much pressure is given to the outflow valve after takeoff to maintain field elevation after 3500ft

Question 62

what is the maximum cabin rate of climb?

Answer 62

550fpm

Question 63

what is max cabin pressure differential?

Answer 63

6 psi

Question 64

at 25000ft, what will the cabin altitude be?

Answer 64

6740ft

Question 65

what is max descent rate of cabin altitude?

Answer 65

400fpm

Question 66

what pressure will the controller set for landing?

Answer 66

landing elevation -300ft

Question 67

what will the digital controller do at touchdown?

Answer 67

open the outflow valves to reach field elevation

Question 68

when is the automatic return feature available?

Answer 68

up to 3500ft

Question 69

what does the FAST button do?

Answer 69

uses a descent rate of 500fpm

Question 70

what is duct temperature limited to in automatic mode?

Answer 70

88c

Question 71

when should we not open the overboard valve?

Answer 71

when differential pressure is more than 1psi

Question 72

what will be triggered if we deselect the exhaust mode push button on the ground?

Answer 72

ground mechanic call

Question 73

what does the ditch push button do?

Answer 73

closes both outflow valves with 2 electric motors powered by the DC EMER BUS

Question 74

what will open if we press the dump button?

Answer 74

both outflow valves

Question 75

what are the indications of a succesful pressurisation test?

Answer 75

18800 -8800 on the digital controller

Question 76

when is the pressurisation test inhibited?

Answer 76

in flight