AIR CONDITIONING

Question 1

How many air conditioning packs are there (200, 300) and where are they situated?

Answer 1

The 200 has 1 pack and the 300 has 2 packs. Located in the tail of the aircraft.

Question 2

What is the purpose of the primary and secondary heat exchangers?

Answer 2

They remove heat from the hot bleed air and feed it to the cabin

Question 3

How are the heat exchangers cooled in flight?

Answer 3

Ram air through the dorsal fin which is drawn over the heat exchanger by the ACM turbine driven fan.

Question 4

What is the purpose of the ACM turbine?

Answer 4

The turbine drives the ACM compressor and the ACM fan. it also acts to expand the compressed air and therefore lowering it’s temperature.

Question 5

How is cabin and cockpit temperature controlled (300)?

Answer 5

The pack temperature control valve which mixes refrigerated air with bypass air, the 300 has two packs, one which feeds the cockpit and the other into the cabin.

Question 6

If the automatic temperature control fails on either pack, what can you do (300)?

Answer 6

The temperature can be controlled using the temperature control knobs. If this fails then the pack should be shut down however the 30 still has one remaining pack.

Question 7

What happens if the CABIN DUCT HOT or FLIGHT COMP DUCT HOT caution light comes on?

Answer 7

A full cold signal will be sent to the respective temperature control/trim valves which will deliver full cool air to the flight compartment or cabin.

Question 8

What is the effect of compressor discharge duct over temperature (Air-conditioning pack overheat)?

Answer 8

The air con pack hot caution light will illuminate and the bleed valves will close, the pack will shutoff until the temperature drops, this can cycle.

Question 9

What is the normal source of air for the air-conditioning system?

Answer 9

Bleed air from both engines and on the ground can be sourced form the APU.

Question 10

When will the avionics compartment fan operate?

Answer 10

The avionics compartment fan operates whenever DC power is availabe

Question 11

Where does the radar get cooling air from?

Answer 11

From the ceiling and floor vents.

Question 12

What valves control cabin temp (200)?

Answer 12

The pack temperature control valves

Question 13

What valves cockpit cabin temp (200)?

Answer 13

The trim valves

Question 14

Where is recirc air drawn from?

Answer 14

under the FWD cabin floor and flight compartment

Question 15

When should the Recirc fans be used?

Answer 15

Whenever the ACM is being supplied with bleed air

Question 16

What can cause the recirc fan to stop operation?

Answer 16

Over temp, over current, under voltage. Automatic shutdown.

Question 17

What input does the cabin temperature controller use?

Answer 17

Temp sensor in the cabin supply duct

Question 18

What input does the cockpit temperature controller use?

Answer 18

Temp sensor in the cockpit supply duct

Question 19

Can the cockpit be cooler than the cabin(200)?

Answer 19

No, the trim valves can only add warm air.

Question 20

What does the computer in the cabin pressure controller do?

Answer 20

Handles all pressure scheduling from take-off to landing with minimal crew input via modulation of the rear outflow valve.

Question 21

Is there negative pressure relief?

Answer 21

Yes, at -0.1 a pressure limiter in the outflow valve will open the outflow valve.