Systems - Air Conditioning Flashcards
In the 200, what does the OFF/FAN/AIR COND switch on the aircondlting panel do?
OFF - Both SOVs are closed and the system is disabled.
FAN - Both SOVs open and the recirculation fan is powered to blow recirculated cabin air into the cargo compartment
COND AIR - Both SOVs open, the heater is enabled and the recirculation fan is powered to blow heated air into the cargo compartment. The heater is controlled by a temperature control switch in the exhaust duct which will cycle the heater ON and OFF as necessary to maintain the cargo compartment temperature between 21°C and 27°C
In the 700/900, what does the record fan switch do?
Turns on both recirculation fans and allows recirculated air to be mixed with conditioned air for the flight deck and passenger cabin.
In the 700/900, what does the conditioned air switch do?
Controls air circulation in the aft cargo bay.
OFF - Closes intake and exhaust SOVs to seal aft cargo bay enclosure
AIR - SOVs opened, recirculated or conditioned air ventilates aft cargo bay
COND AIR - SOVs opened, recirculated or conditioned air ventilates the aft cargo bay. Electric heater maintains bay temperature.
Selecting Conditioned air provides automatic temperature control to the cargo compartment. Controlled by ACSC2 the system regulated the aft cargo bay temperature between 16°C and 27°C. When the compartment temp drops below a predetermined level an electro heater turns on automatically.
If on the ground an <200> CARGO OVHT or <700/900> AFT CARGO OVHT message illuminates, can we depart?
Yes, if this occurs with live cargo loaded in the cargo compartment, keep the switch in the COND AIR position, make sure the cabin temp control is set to COLD and if possible, close the cargo door.
On the 200, what is the significance of the CARGO OVHT message?
An overheat switch in the exhaust duct provides over temperature protection by removing power from the heater when the exhaust duct temperature > 49°C. A signal is also sent to the EICAS to display a CARGO OVHT caution message. The switch will reset when the temperature decreases below 29°C
When setting the cabin temperature, are we setting temperature or valve position?
Automatic Mode: Output temp.
Manual Mode: Valve position
Can we see an actual select temperature?
Yes, in automatic mode, the actual and selected temperature for each compartment are displayed on the ECS synoptic page. The passenger cabin’s actual temperature is also displayed on the EICAS status page.
What happens if full cold is selected in Manual Mode on a 200?
In manual mode select temperature below 3°C may result in icing of the water separator and subsequent cycling of the pack
What happens if full cold is selected in Manual Mode on a 700/900?
If pack discharge temp is <=5°C, the L or R PACK TEMP caution message is displayed.
