Air Conditioning And Pressurization Flashcards
What controls the ram air regulating valve(RAVR)
The air conditioning system controllers
ACSC’s
ACSC
Air conditioning system controllers
In the event of dual pack failure what provides air
Ram air switchlight
Using the ram air switch light the air enters which supply system
The left supply system
How many avionic cooling fans
Fan 1 … Operates during flight or on the ground as alternate
Fan2… Operates on the ground or in flight as alternate
Standby fan operates as backup
When smoke is detected in the cargo bay
The heater power is removed and the shut off valves automatically close
How many Galley heaters do we have
Two 500 W heaters to supply heat to the galley and Service door area
Cabin pressure is maintained and controlled by
1 electro pneumatic outflow valves
If cabin altitude exceeds 14,000 feet
Passenger oxygen masks deploy
3-13
The outflow valves are automatically controlled by
Either of two independent Cabin pressure controllers
How many CPC’s
2
The pressure controller automatically switches on the ground when
On the ground for three minutes
The active CPC is displayed on the ECS synoptic page
EMER DEPRESS
Opens bothoutflow valves
14500 +-500
FASTEN SEATBELT SIGN
and
NO SMOKING SIGN
comes on automatically when
Cabin altitude is at or above 8500 feet
Px sign in auto
Do we have a CPAM
No
Amber fault light on one of the packs?
Failed in both auto and manual
Amber fault lt on the PRESS CONT Switch?
Both cabin pressure controllers have failed
When is pressurization data shown on the primary page
When in manual mode
What cools packs
Ram air
Ram air also provides cooling airflow to
Cooling of number one and two hydraulic system fluids
How many recirc fans
2
Test question
Low-pressure compressed air from a ground air conditioning cart can be supplied directly to
Into the flight and passenger compartment distribution systems
What are the two avionics exhaust fans used for
To extract the heated air from behind the flight compartment displays and from the avionics equipment
On the ground the heated air is dumped overboard through the ground outflow valve
Inflight the heated air is ducted to the pressurization outflow valve and dumped overboard
8-30-1 mes psm
OVBD COOL FAIL status?
“Overboard exhaust shutoff valve Has failed closed with the aircraft on the ground and the passenger door unlatched” QRH definition
- Ground valve fails to open after touchdown— SYS 3-24
OVBD COOL caution
Over board exhaust shutoff valve is not closed with the passenger door and service door closed
Aircraft will not pressurize
How many electrically controlled outflow valves regulate the cabin pressure
One!! This is a correction to a previous card
How many safety valves
Two…
One for overpressure relief
failedOne for negative pressure relief
Cabin altitude exceeds 14,000 feet
O2 masks deploy
14000 +-300
CABIN ALT WARNING
cabin altitude is greater than 10,000 feet
DIFF PRESS WARNING
differential pressure greater than 8.6 PSI
CABIN ALT caution
Cabin altitude is greater than 8500 feet but not greater than 10,000 feet
OVBD COOL caution?
Ground valve failed open with passenger and service door closed
What is the cabin altitude limitation regarding the pressurization system
The outflow valves will close to prevent The cabin from increasing above 14,500 +-500
Pressurization is controlled by
A single electric controlled outflow valve
ACSC stands for
Air conditioning system controller
2 ACSC’s
#1 ... Left HPV. LCV ISOL #2....right HPV
2 channels/controller
1 active /1standby
No EICAS indication for activechnnel
ACSC PROVIDES ?
Ice protection 4 packs
Auto shutdown
2 flowrates
PRSOV fail safe?
Closed
How many pressurization valves
1
Completely electric
What happens if both CPC’s fail?
Outflow valves go to a barometric hold
Recirc fan off at what temp?
OFF if “cabin” temp is greater then 30 degrees
Ground valve functions in 2 Ways
Ensures aircraft is depressurized on the ground
Allows avionic warm air to dump
FAULT. Lt on pack switch?
Failed in both auto and man modes
Mes 8-20-3
Ram air passes over the packs for cooling and is then vented overboard thru
An exhaust vent on the lower aft fuselage
Where is px compartment exhaust air routed?
Underfloor to the outflow valves
Flt compartment exhaust air is routed?
Underfloor through the avionics compartment to the outflow valve
Display fans ?
( 2 display fans) 1 fan draws in air from the flight deck and mixes it w/ conditioned air and supplies it ti the back of the each display.
Avionics fans?
Used to extract heated air from bhind flt comp displays and from avionics equipment.
In gnd .. Heated air dumped overboard .. Gnd valve
In flt … Outflow valve
Cargo switch .. Off pisition?
Both shutoff valves closed, system disabled
Air position?
Both shutoff valves open.. Recirc air keeps temp abv freezing
Cond air?
Both SOV open , heater enabled
Cabin altitude limitation?
Outflow valves close cabin altitude about 14,500 feet
What happens when either engine start switch light is pressed?
The pack. Valves automatically close
Controlled by a ACSC
How many pressure schedules?
2
Normal pressure for two packs
Increased pressure for one pack
FAULT light on the pack switch?
Pack has failed In both automatic and manual mode
left right pack caution
When should the recirc fan switch be selected to off?
When cabin temperature is warmer than 30°C
Recirc fans pool air from…
Cabin floor and returns it to mixing manifold
Are both forward and aft cargo bays pressurized?
Yes
Which cargo bay is ventilated by conditioned air?
Only the aft cargo bay
Aft cargo switch should not be selected to conditioned air when?
Ambient temps are above 15°C
How are all phases of pressurization controlled in the Auto mode?
Through two cabin pressure controllers
Only one controller is active
Switches three minutes after WOW
How many outflow valve?
1
Located on aft pressure bulkhead
How many safety valves?
2
Provide overpressure and negative pressure relief
How are the safety valves operated?
Pneumatically operated and spring loaded closed
What is the purpose of the ground valve?
Ensures aircraft is depressurized on ground
Also dumps CRT and avionics air overboard
When do oxygen masks drop?
14,000 feet plus or -300
Cabin alt caution?
8500 feet
With a failure of the CPCP??
Auto oxygen mask deployments and illumination of fasten seatbelt and no smoking signs will not occur
2 display cooling fans..
Fan 1 gives cooling during flight
Fan two gives cooling on the ground
Standby:conditioned air cools displays
( no fan)
Cabin altitude limitation?
14500 +- 500
The outflow valve will close to prevent an increase in cabin altitude
How many outflow valve’s
1
How many safety valves
2
Overpressure
Under pressure
( mechanical)
Are the cargo compartment pressurized
Yes
Maximum positive differential pressure
8.6
Negative differential pressure is limited to
-.5 psi
RAVR?
Ram air regulating valve
Nornally open
Status? Failed open or towards closed
Left pack auto fail master caution
Failure of respective pack in automatic mode… and system not in manual mode
Ram air enters which side
The left side
The flight compartment CRTs fans?
Avionics cooling fans
Fan 1 operate during flight
Fan 2 operates on the ground
Standby fan as back up
Selecting STBY on the avionics cooling fan does what?
Permits conditioned air to ventilate the displays
Test: CARGO OVHT
cargo bay temperature greater than 35°C
Test: CARGO OVHT
cargo bay temperature greater than 35°C
SINGLE OUTFLOW VALVE!!!
SINGLE OUTFLOW VALVE!! 6/7/20
The packs are cntrolled by?
ACSC
Air conditioning system controllers
Recirculation fan must be switched off when the cabin temperature is warmer than
30 degrees
AFT CARGO SWITCH?
Do not select conditioned air if ambient temperatures are above 15°C
In the avionics cooling system selecting standby on display cooling will?
Turn off fans to have conditioned air cool the displays
PACK MEANS?
Pneumatic air conditioning kit
FAULT LIGHT on pack switch?
Pack has failed in both automatic and manual mode
3-3 systems ac and press 6/7/20
ACSC 1 Controls the left pack
ACSC 2 controls the rt pack
3-3 systems
There are two air-conditioning system controllers.. Each controller has?
Two parts one of which is active the other is standby and monitors
When a pack is operated in manual mode the selected temperature indicated for the associated pack is?
Removed from the ECS synoptic page
RAM AIR VALVE Allows air from the ram air scoop to enter the mixing Manifold For distribution to?
Both the flight deck and the passenger cabin
3-9 systems ac and press 6/7/20
The cargo conditioned air is controlled by?
ACSC2
How many safety valves?
Operated?
There are two safety valves in the pressurization system pneumatically operated
Spring loaded closed
At 8500 cabin alt
No smoking fasten seatbelt sign
If in auto
Maximum differential pressure
8.6 +-.1
3-23 systems ac and press 6/7/20
Cargo htr temp?
70 - 80
FAULT lt on pack ?
Failed in both automatic and manual mode
Aft cargo been heater maintains what temperature
Between 70 to 80°F
3-14
Cargo overheat caution when temperature exceeds what temperature in the aft cargo compartment
95°F
What is used to cool the equipment in the avionics bay?
Exhaust air from the flight deck cabin and CRT displays
3–17
In manual mode, how is the outflow valve controlled?
Electrically by switches on the cabin press panel
