Exercise 3 - Ancillary Controls Flashcards
1
Q
Mixture Control - What is it?
A
- Allows pilot to adjust mixture of fuel and air to adapt to changing conditions
2
Q
Mixture Control - Why We Need It
A
- Air density decreases
- proper combustion requires a correct mixture by mass
3
Q
Mixture Control - How it Works
A
- “leaning” the mixture by adjusting out will reduce fuel mass
- good for efficient cruise at higher altitudes and higher humidity
- “enriching” the mixture will increase the fuel mass
- good for maximum power at low altitudes
4
Q
Mixture Control - Factors Affecting Air Density
A
- Altitude, density decreases with increase in altitude
- Temperature, density decreases with increase in temperature
- Humidity, density decreases with increase in humidity
- Carburetor Heat increases temperature, reducing density
5
Q
Mixture Control - How We Use It
A
- POH contains detailed instructions
In General: - Mixture should be slightly lean of full rich for taxi (1-2 twists)
- Full rich for takeoff
- Full rich for climb
-“rich best power” for cruise, lean to maximum RPM - Progressively rich the mixture for descent
- Full rich for landing
- Generally better to be slightly on the rich side
6
Q
Mixture Control - Too Rich (Excessive Fuel)
A
- Will not develop full power
- Will run unevenly
- May operate cooler than desirable
- Fuel is wasted
- Spark plug fouling may occur
- Range is Reduced
7
Q
Mixture Control - Too Lean (Excessive Air)
A
- Power will be lost
- Will run rough/vibrate
- May operate hotter than is desirable
- Damage may occur from prolonged operation
8
Q
Carburetor Heat - Why We Need It
A
- May not need it
- Fuel injected aircraft do not have carburetors, meaning they don’t need a carburetor heat system
- Air is cooled up to 30º as it passes through the throttle (pressure drops and fuel vaporization both cause cooling)
- This can cause ice to form and eventually block airflow to the engine
9
Q
Carburetor Heat - What it Does
A
- Allows us to direct hot air into the carburetor, melting ice
10
Q
Carburetor Heat - How it Works
A
- Air that has beed heated by the exhaust system is directed into the carburetor
- Any ice that is present will be melted and new ice will not form
11
Q
Carburetor Heat - Carburetor Ice
A
- Formation is a function of environmental conditions and power setting
- Forms in high humidity conditions between -5ºC and 30ºC
- Formation is most severe between -5ºC and 15ºC
- Low Power significantly increases risk due to restriction of the throttle package
- Ice buildup reduces engine power (visible in RPM indications)
- Must be vigilant because ice can develop rapidly
12
Q
Carburetor Heat - Proper Use
A
- Carb Heat should be on anytime the RPM is outside of the normal operating range (green arc) in flight
- Applying carb heat first when reducing power is key (might not work if engine is already too cool)
- Set carb heat cold last when increasing power
- When carb heat is turned on and there is a decrease in RPM, there is no icing
- When carb heat is turned on and there is no change or an increase in RPM there is icing
13
Q
Carburetor Heat - Use Considerations
A
- Carb heat is unfiltered, minimize use on ground
- Hot air is less dense and enriches mixture so RPM will reduce when carb heat is hot
- Carb heat can raise the temperature into the carb icing range in extremely cold conditions
14
Q
Cabin Heating and Cooling - Why We Need It
A
- Windshield defogging
- Pilot Comfort
15
Q
Cabin Heating and Cooling - What It Does
A
- Supplies fresh air to cabin (either hot or cold)
