Air Conditioning

Question 1

Describe Auto and Manual operations of the temperature control.

Answer 1

AUTO MODE:
– Temperature knobs pressed in
– Maintains a temperature between 18°C (65°F) and 29°C (85°F)
MANUAL MODE:
– Temperature knobs pulled out
– No temperature range is established
– MUST monitor temperatures

Question 2

Describe the amplified procedure for Air Conditioning set during the Receiving Check?

Answer 2

Set the temperature control knobs to the desired position. The cabin knob should be set to the ATTD position to allow the Flight Attendant to control the cabin temperature.

If the APU is being used to heat or cool the cabin, the XBLEED knob should be selected OPEN so both PACKs receive air. The RECIRC and GASPER pushbuttons should normally be selected in.

If a ground air cart is supplying air, the PACKs must be selected off to prevent damage to the cabin air distribution system.

The time required to cool the cabin may be reduced by turning the RECIRC to OFF. Once the desired cabin temperature is reached, the RECIRC should be selected ON.

Question 3

May PACKS be selected if a ground air cart is supplying air?

Answer 3

If a ground air cart is supplying air, the PACKs must be selected off to prevent damage to the cabin air distribution system.

Question 4

How is the forward electronic compartment cooled?

Answer 4

Recirculation fans in the bay run continuously when the aircraft is powered.

If the temperature rises above a set value, two exhaust fans turn on to assist in cooling
• Air enters through NACA inlets and exits through exhaust vents

Question 5

Describe the amplified procedure for Bleeds and Packs set during the After Takeoff Check?

Answer 5

Engine Bleeds: OPEN
APU Bleed: CLOSED
Cross-bleed: AUTO
Packs: ON

Question 6

What is the highest allowed altitude for single pack operation?

Answer 6

FL250

Question 7

When should the crew consider turning the Recirculation Fan OFF while parked at the gate?

Answer 7

If the air outside is more comfortable than the air inside.

Question 8

What is the purpose of the GASPER fan?

Answer 8

Cannot be shut off on the ground.
Provides air for:
– Passenger outlets
– Rear electronic bay
– O2 cylinder compartment

Question 9

Under what conditions will the PACKS shut off automatically?

Answer 9

For TO and E-TO, if using engine bleeds our Packs may shut off during takeoff below 1,700’ AGL.

Question 10

How would the PACKS operate during icing conditions at 2000’ AGL in CLB thrust?

Answer 10

PACK 1 is off, PACK 2 is on

Question 11

How would the PACKS operate during a go-around at 1100 AGL?

Answer 11

Both PACKS would turn off

Question 12

What is the maximum operational altitude with one PACK inoperative?

Answer 12

FL250

Question 13

What are the Ram Air Doors and when would they open?

Answer 13

NACA vents on the underside of the fuselage. Ram air doors in “emergency” position allow ambient air to flow into the cabin but will not pressurize the cabin. They open/go to emergency position any time the aircraft is in flight with both PACKS off.

Question 14

How is the baggage compartment ventilated?

Answer 14

Air flows from the passenger cabin through a check valve into the baggage compartment, on its way to the outflow valves.

Question 15

What is the air distribution for PACK 1 and PACK 2?

Answer 15

PACK 1 is 80% cockpit, 20% cabin

PACK 2 is 20% cockpit, 80% cabin