324 Air Conditioning

Question 1

What are the two main types of Air Conditioning?

Answer 1

AirCycle Machines (aka Air Packs)

Vapor-Cycle Systems

Question 2

Where are air cycle machines found?

How does it function?

Answer 2

Found on turbine aircraft.

Compressed air is bled from turbine engine and expanded for cooling.

Question 3

Where do you find Vapor Cycle Systems?

How doe sit function?

Answer 3

♣ Used on light reciprocating engine aircraft

♣ Pressurized liquid refrigerant (Freon) evaporates, causing temperature reduction.

Question 4

What turns the compressor in the Vapor Cycle System?

Answer 4

The Crankshaft

Question 5

High pressure = _____ energy

Answer 5

High Energy

Question 6

Why do air conditioners suck in aircraft? (in a nutshell)

The Compressor
The Condenser
Blowers

Answer 6

• Compressor: robs power
• Condenser – in lipstream (increases drag)
• Blowers – electrical (robs power )

Question 7

If you see a light reciprocating aircraft it’s going to have a ____________

Answer 7

Vapor Cycle System

Question 8

Air Conditioners (Vapor Cycle Systems

Where is it not commonly found?

Operating and initial purchase are ________

Operation decreases in _____ and _______

Increases what kind of drag?

Weight penalty lowers the __________

Must be turned off during _______ and _______ operation.

Must be turned off prior to _______ for possible ________.

Answer 8

• Not commonly found on low powered single or multi engine light aircraft
• High initial purchase and operating costs.
• System management adds to pilot workload.
• Operation decrease in cruise speed & range.
• Increase in skin friction drag
• Weight penalty lowers useful load
• Engine power required to run compressor decreases thrust output
o Must be turned off during takeoff nad max performance operation
o Must be turned off prior to landing approach for possible go around

Question 9

What’s another name for air cycle Machines?

Answer 9

Air Pack

Question 10

How does it operate (4)

Answer 10

1. Bleed air is cooled
2. Air is compressed, reheating it to 250c
3. Air is sent through secondary heat exchanger
4. Air now travels through expansion turbine, dropping air below ambient temperature.

Question 11

Air Pack / Air Cycle Machines are similar to normal air conditioning however, __________ is used to cool air rather than _________.

Answer 11

Ambient air is used to cool air rather than chemical coolant (freon)

Question 12

What is the chemical in vapor cycle systems?

Answer 12

Freon

Question 13

Air Cycle Machines feed air to what four places often?

Answer 13

• Cabin
• Lavatories
• Galley
• Individual seat gaspers ( what we have in the cessnas )

Question 14

What are the open and close knobs on our C172s called?

Answer 14

Gaspers

Question 15

what do Zonal Dryers do:

Answer 15

Dry the ambient air to prevent mildew or mold over the life of the aircraft (dehumidifier)

Question 16

Exhaust Manifold Heater

Where is it found?
• Simple but effective system if

Answer 16

Found in single engine airplanes.

• Simple but effective system if properly installed, inspected, maintained.

Question 17

Advantages to Exhaust Manifold Heaters (4)

Answer 17

Advantages:

• No reduction in performance
• No consumption of fuel
• No reduction of engine power
• No decreased airspeed or ranger

Question 18

Disadvantages to Exhaust Manifold Heaters (4)

Answer 18

• Ineffective ground heater
• Poor windshield defrosting
• CO poisoning threat ( Ram air is passed through a shroud over engine exhaust manifold and ducted into cabin)

Question 19

What are the two basic types of Heating Systems?

Answer 19

Exhaust Manifold Heaters

Combustion Heaters

Question 20

What are the two types of combustion heaters?

Answer 20

• Janitrol combustion heater (Seminole)

* Stewart Warner South wind Heater

Question 21

Combustion Heater
What’s the benefit of combustion heaters?
What air craft is it most commonly found on.
Where is it most often located
What monitors it’s usage?

Answer 21

• Instant heat without starting engine
• Found on most multi engine planes
• Located in forward fuselage nose cone
• Separate Hobbs to monitor usage

Question 22

Combustion heater:

When does it require routine overhaul?

When is it turned off?

What does it to do to aircraft range.

More complicated than ________.

Danger still exists from CO and ______.

May not start if it’s _____.

Answer 22

• Requires routine overhaul (generally every 500 hours or 24 months)
• Generally turned off during takeoffs and before landings (follow POH)
• Shorten aircraft range
• More complicated operation than exhaust manifold
• Danger from CO and FIRE
• May not start (COLD!)

Question 23

Combustion Heater Advantages

Answer 23

• Effective ground heater

* Good windshield derfrosting

Question 24

Combustion Heater Disadvantages (2)

Answer 24

• Reduced flight performance
o Consumes fuel
o Decreases range
• CO poisoning threat but less than Manifold Exhaust

Question 25

Things that can get you in big trouble: (4)

Answer 25

• Carbon Monoxide
• No Heat
• Windshield Fogging
• Janitrol heater Inop

Question 26

Considerations as a commercial pilot

Answer 26

• As a commercial, air taxi/charter, or regional airline pilot you are responsible for passenger comfort and safety.
• Consider loading passengers in heated/cooled hangar, just prior to departure.
• Continually check on passenger comfort during flight.