Air Conditioning and Ventilation Flashcards
Each of the 2 AC Controller is divided up into…
2 Lanes
What happens to the PACKs during TO and Landing?
The inlets and outlet close to prevent FOD
How is PACK air temp regulated?
Throttling the Bypass Valve warms the air with hot air bypassed from the primary HE
What does the valve icon on the BLEED status page represent?
The bottom valve is the Pack Flow Control Valve position. The upper valve is the Bypass Valve position
What regulates the different zone temperatures?
The addition of bleed air warms compartments that are required to be warmer than the coldest set compartment.
What is the purpose of the recir fans?
By recirculating the air, bleed air demand is reduced leading to fuel savings
Why would the mixing unit line at the top of the BLEED page be amber?
Pack flow control valves and ram air inlet are closed
Why would you receive a FAULT Pack fault light?
Pack flow control valve disagrees with commanded position, Pack compressor overheat, Pack outlet temperature overheat (note: valve closes auto during an overheat condition)
What are the extreme and middle temperature settings on the control knob
COLD = 18C
12 o’clock=24C
HOT=30C
What does the FAULT on the HOT AIR pb indicate?
Duct overheat
What if you see PACK faults during pre-flight?
This is normal, indicating that there is not enough bleed air pressure for the packs until the APU or Engine Bleed is opened.
Your aircraft has less than 115 people, what Pack Flow setting should you set?
LO, to conserve fuel
You select the RAM AIR to open but it does not react as commanded, why?
The valve will only open if Delta Press is less than 1.0 psi. Basically, you need to descend.
When should you select LO on the PACK FLOW selector?
When passenger count is < 168.
IT reduces pack flow up to 20%
How are the zone temperatures individually controlled?
- Temperature regulation is controlled by 2 air conditioning system controllers.- Temperature regulation is optimized via the hot air pressure regulating valve, and the trim air valves that add hot air, tapped upstream of the packs, to the air coming from the mixing unit.
What controls the packs and TAVs?
Pack operation is controlled by air conditioning system controller signals.
What happens to the system during engine start?
- If the crossbleed valve is closed, the valve located on the staring engine side immediately closes, when the mode selector is set to IGN or CRANK.
- It remains closed on the starting engine side (provided the crossbleed valve is closed) when:
a. MASTER SW on
b. Start valve is open
c. N2 <50% - On the ground, reopening of the valves is delayed for 30 secs to avoid a supplementary pack closure cycle during 2nd engine start.
What happens when a duct overheat occurs?
- The FAULT light come son amber.- ECAM caution, when duct overheat is detected.- The fault circuit detects an overheat when the duct temperature reaches 80 degrees once.
When does the Pack Ram Air Inlet Flap close?
T/O: takeoff power is set and the main landing gear struts are compressed.
LDG: as soon as the main landing gear struts are compressed, as long as speed is greater or equal to 70kts. They open 20sec after speed drops below 70kts.
What 3 conditions could cause the Pack Flow to be Higher than the selected on the overhead panel?
- In single-pack operation
- When the APU is supplying bleed air
- When temperature cannot be satisfied
The compartment temperature controllers can be set to what range of temps?
18 – 30 degrees Celsius
What happens if an ACSC has a LANE failure?
No effect, as the second lane takes over.
What happens if an ACSC has a double LANE failure?
Related pack is lost (ACSC1 – flight deck, ACSC 2 – cabin), Hot Air Pressure Regulating Valve and associated Trim Air Valves close.
When does a Pack Overheat FAULT light, (on OHP) extinguish?
When the temperature drops < 70 degrees and the flight crew selects OFF.
What happens when the Ram Air Pushbutton is selected ON?
If the DITCHING p/b, on the CABIN PRESS panel is in normal position:
- Ram Air Inlet opens
- If delta P is greater or equal to 1 PSI, no emergency Ram Air flow in (Closed)
- If delta P is less than 1 PSI, outflow valve opens to 50% when under automatic control. It does not automatically open when it is under manual control. Emergency RAM airflow is directly supplied to the mixer unit.
What limitations apply to the opening of the Ram Air Valve?
Only open if differential pressure is lower than 1 PSI.
The LO pack flow setting thresholds.
LO: if the number of occupants is below 168.
What is the OPEN configuration?
In warm ambient climates (>50F), the blower motor takes outside air, blows it over the avionics and discharged by the extract fan and valve..Both blower and extraction valves are OPEN
What is the CLOSED configuration?
In cold ambient climates (<50F), the blower and extract fans operate when the valves are closed, circulating air from inside the fuse only.Both blower and extraction valves are CLOSED.Condition after TOGO power, in-flight to landing
What is the intermediate configuration?
In very hot climates (>90F), the extract valve is partially open during TO until colder ambient conditions are reached.
What controls the Avionics ventilation system?
Avionics Equipment Ventilation Computer (AEVC)
What is unique about our cargo compartments?
Cargo heat is disabled, we do not carry pets!!
Why would the inlet and extract valves be amber?
The valve position does not agree with the commanded position
OR
The valves are in transit
When would a BLOWER fault illuminate?
Blower fan low pressure
Duct overheat
Computer power supply failure
Avionics smoke
When would a EXTRACT fault illuminate?
Extract fan low pressure
Computer power supply fails
Avionics smoke
What happens when you press OVRD on the BLOWER or EXTRACT pb
The blower or extract fan stops and air conditioned air is introduced.Note: In normal conditions, the bay is cooled by the skin heat exchanger to save fuel.
What is the serious in-flight failure in regards to avionics
Extract valve opens in flight which can compromise pressurization.Note: In inlet duct has a non-return valve to present this if the inlet valve opens.
What indicates smoke int he avionics bay?
MASTER CAUTSMOKE light on GEN ! LINEFAULT on both BLOWER and EXTRACTAVNCS SMOKE message
In the “Ground” Mode at High Skin Air temperatures, which Config is in operation?
The open-circuit configuration operates when skin temperature is above the on-ground-threshold from +12 degrees to +9 degrees.Inlet valve – blower – avionics – extract – extract
In the “Ground” Mode at Low Skin Air Temperatures, how is the Circulatory Air now cooled?
The closed-circuit configuration operates when skin temperature is beneath the on-ground threshold.Avionic bay – heat exchanger – cargo underfloor
In the “Flight” Mode at Low Skin Air Temperatures which Config is in operation?
The closed circuit configuration operates when skin temperature is beneath the in flight threshold of +35 degrees to +32 degrees.Heat exchanger – cargo
In the “Flight” Mode at High Skin Air Temperatures which Config is in operation?
The intermediate configuration operates when skin temperature is above the in-flight threshold of +35 degrees to +32 degrees.Heat exchanger - cargo – extract
What causes the system to transit from the GROUND mode to the FLIGHT mode?
Takeoff power + weight on gear
When might you have to put both switches (BLOWER and EXTRACT) to OVERRIDE?
Smoke / fumes / avionics smoke
What causes a BLOWER or EXTRACT FAULT light to illuminate?
- Pressure is low (blowing + extract) inhibits for engine shut down.- Duct overheat (blower)- Computer power supply falls- Smoke warning is activated
What happens when the BLOWER is selected to OVERRIDE?
When either p/b switch is on OVRD:- The system goes to closed circuit configuration.- Air from the air conditioning system is added to ventilation air.- The blower fan stops if BLOWER p/b is on OVRD.
What happens when the BLOWER and EXTRACT are selected to override? (E.g. during AVIONICS SMOKE)
When both p/b SW are on OVRD:- Airflows from the air conditioning system and then overboard- The extract fan continues to run
What is the purpose of the ram air?
An emergency ram air inlet ventilates the cockpit and cabin to remove smoke or if both packs fail.
What is the function of the mixer unit?
This unit mixes cold fresh air from the packs with the cabin air being recirculated through recirculation fans.
What is the function of the trim air valves?
These valves are electrically controlled by the air conditioning system controllers. The cockpit trim air valve and the cabin trim air valves adjust the temperature by adding hot air.
What is the function of the APU flow demand?
When the APU bleed valve is open the air conditioning system controller signals the APUs Electronic Control Box (ECB) to increase the APU flow output when any zone temperature demand cannot satisfied.
For which zones is an independent temperature control possible?
Cockpit fwd cabin and aft cabin.
Is a temperature control from the cabin possible?
Yes during cruise the cabin crew can modify each cabin zone temperature that is selected from the cockpit with a limited authority of +/- 2 5°C or +/-4 5°F.
What is the function of the pack flow control valve?
This valve regulates the air flow in accordance with signals received from the air conditioning system controllers.
What is the temperature selection range?
The temperature selection range is from 18°C to 30°C.
Under which condition should the pack flow controller be set to LO?
With a low passenger load to reduce bleed air demand and improve fuel efficiency.
Under which circumstances delivers the air conditioning system high flow?
In single pack operation or when the APU is supplying bleed air.
Under which condition should the pack flow controller be set to HI?
With a high passenger load in hot conditions in order to help reduce the cabin temperature.
What happens to the pack flow control valves during engine start?
They automatically close.
How is the pack flow control valve controlled and operated?
The valve is electrically controlled and pneumatically operated.
The PACK FLOW controller is set to NORM and the ECAM display shows PACK FLOW to be high. How is this possible?
High flow is automatically selected regardless of PACK FLOW sel position because air is only being supplied by the APU.
In which cases closes the pack flow control valve?
The Pack flow control valve closes automatically in case of pack overheating engine starting or operation of the fire or ditching pushbutton.
What is the purpose of the hot-air pressure-regulating valve?
This pneumatically operated and electrically controlled valve regulates hot air pressure which is tapped upstream of the packs.
How can you operate the emergency ram air inlet valve?
The emergency inlet valve is controlled by the ram air pushbutton on the air cond panel. This pushbutton opens the ram air valve provided that ditching is not selected.
What happens if the Air Cycle Machine (ACM) fails?
The affected pack may be operated in heat exchanger cooling mode. Warm pre-conditioned bleed air enters the cooling path via the pack valve and goes to the primary heat exchanger. The main part of the cooled air goes directly downstream of ACM turbine though the bypass valve and the rest goes though the failed ACM.
Where are temperature sensors located?
In the cockpit for the cockpit zone in the lavatory extraction circuit and galley ventilation system for the cabin.
When does the hot-air pressure-regulating valve close automatically?
This valve closes automatically if the duct overheats the cockpit trim air valve fails or both cabin trim air valves fail.
How does the Air Conditioning System Controller configure its associated pack ram air inlet flap for takeoff and landing to avoid the ingestion of foreign matter?
TAKEOFF: Ram air inlet flap closes when takeoff power is set and the main landing gear struts are compressed. Ram air inlet flap re-opens after main landing gear strut extension. LANDING: Ram air inlet flap closes as soon as the main landing gear struts are compressed and speed is great than or equal 70 knots. Ram air inlet flap opens 20 seconds after speed <70 knots
What is the function of the HOT AIR pushbutton?
Control the hot air pressure regulating valves which controls the flow of hot air to the trim air valves. This hot air is mixed with the pack-conditioned air for zone temperature control
What does an amber “FAULT” light in the HOT AIR pushbutton indicate?
Duct Overheat - the hot air and trim air valves close automatically
Describe how the Air Conditioning System Controllers regulate temperature?
BASIC temperature regulation: Both packs produce the required outlet temperature determined by the lowest demanded zone temperature. OPTIMISED temperature regulation: Hot air is added to the individual zones by the trim air valves to maintain the desired zone temperatures
What occurs when both lanes of an Air Conditioning System controller fails?
The related pack is lost. The hot air pressure-regulating valve and associated trim air valve(s) close
What causes the Pack Flow Control valve to automatically close?
Upstream pressure below minimum. Pack overheat.
Engine start sequence.
Engine FIRE pushbutton on the related side pressed.
DITCHING pushbutton selected.
What would cause an amber “FAULT” light to illuminate in the PACK 1/2 pushbutton? (OOD)
Overheat - pack outlet.
Overheat - compressor outlet. Discontinuity - switch position disagreement with pack flow control valve
What effect will the engine starts sequence have on the pack flow control valves?
The pack flow control valves will close automatically
The PACK FLOW selector has LO, NORM, and HI positions. What does this allow us to do?
Select pack flow rates representing LO 80%, NORM 100%, and HI 120% of norm
When should the PACK FLOW selector not be in the normal position?
Less than 168 pax, select LO.
Hot/Humid conditions, select HI. During smoke/fumes removal select HI as per the procedure.
If an air cycle machine (ACM) fails, what occurs?
The affected pack will operate as a heat exchanger
When is air conditioning introduced into the Avionics Compartment?
Abnormal operation and SMOKE configuration
How many Air Conditioning System Controllers are there?
2, Each Air Conditioning Controller has 2 lanes: Active/Standby
What occurs when an active lane of an Air Conditioning System Controller fails?
The second lane takes over
The ventilation system includes ventilation for…
The avionics (controlled be the avionics equipment ventilation controller), the battery, the lavatories and galleys.
How does the smoke configuration work?
When the smoke detector detects smoke in the avionics ventilation air the BLOWER and EXTRACT FAULT lights come on. When both the BLOWER and the EXTRACT pushbuttons are set to OVRD position the ai conditioning system supplies cooling air which is then exhausted overboard. The blower fan stops.
What are the main components of the avionic ground cooling?
1 inlet valve, 1 ground cool fan, 1 cooling unit, 1 outlet valve and one controller.
With the BLOWER and EXTRACT pb switches in AUTO what ventilation configuration do you normally expect to see?
Open configuration on the ground before applying T/O power and closed configuration after applying T/O power in the air.
How does the battery ventilation work?
A venturi in the skin of the aircraft draws air from the space around the batteries and vents it overboard. The resulting airflow ventilates the batteries.
On which ECAM page you will get information about the ventilation system?
PRESS page.
With the BLOWER and EXTRACT pb switches in OVRD what happens to the ventilation system?
The system goes into the smoke configuration and the blower fan stops.
When does the avionic ventilation in the open-circuit configuration operate on the ground?
The open-circuit configuration operates when the skin temperature is above the on-ground threshold: +12°C (53°F) temperature increasing or +9°C (48°F) temperature decreasing.
What is the purpose of the avionic ventilation?
The avionic ventilation system is fully automatic. It cools the electrical and electronic components in the avionic compartment and on the flight deck including the instrument and circuit breaker panels.
During ground function operation the outflow valve is…
Fully open.
What are the main components of the avionic ventilation?
Fans skin air inlet and extract valves skin exchange inlet and outlet bypass valves airconditioning inlet valve skin exchange isolation valve and Avionics Equipment Ventilation Computer (AEVC).
When does the Lav/Galley extract fan operate?
Continuously when electrical power is available
What does an amber “FAULT” light on the BLOWER pushbutton indicate?
- SMOKE warning is activated- Computer power supply failure- Low Blower pressure- Duct Overheat
What does an amber “FAULT” light on the EXTRACT pushbutton indicate?
- SMOKE Warning is activated- Computer power supply failure- Low Extract Pressure
With 2 FAULT lights on the VENTILATION panel, are there any other indications?
Yes, the SMOKE light in the GEN 1 LINE pushbutton
What is the RAM AIR pushbutton used for?
- Smoke removal in cabin- Ventilation of cabin with a dual pack failure
Will there be any other indications?
ECAM warning and amber “FAULT” lights in the EXTRACT and BLOWER pushbuttons on the VENTILATION panel
With BLOWER and EXTRACT pushbuttons in AUTO how does the system operate?
- Ground: system is normally in the OPEN configuration- Flight: system is normally in the CLOSED configuration- Intermediate: Closed configuration except small internal flap in Extract Valve is open.
With both BLOWER and EXTRACT pushbuttons in OVRD (smoke configuration) what are teh positions fo the INLET and EXTRACT valves?
- INLET valve closed- EXTRACT valve OPEN
With a CARGO SMOKE warning what happens to the Isolation Valve and Extract Fans?
- Isolation Valve closes- Extract Fans stop
What does the CARGO HEAT AFT ISOL VALVE amber “FAULT” light indicate?
Valve disagreement of inlet or outlet valve
What is the purpose of the CABIN FANS?
To re-circulate cabin air to the mixing chamber and then back to the cabin
What does the CARGO HEAT HOT AIR amber “FAULT” light indicate?
Duct Overheat
