Operation of Systems

Question 1

What errors can occur with the airspeed indicator?

Answer 1

• Position error: Due to the dynamic air from the spiraling slipstream disturbing the air at the static port causing ±errors
• Density Error: The ASI doesn’t compensate for varying temperature and altitude (i.e. TAS)

Question 2

What are the different types of airspeeds?

Answer 2

CAS: Airspeed corrected for instrument installation errors. CAS & TAS are equal at sea level when temps are standard

TAS: CAS corrected for non-standard temperature and altitude. It’s the actual airspeed the aircraft is actually moving through the air

IAS: The airspeed that’s indicated on the ASI instrument

Question 3

What are the different color airspeeds indicated on the ASI?

Answer 3

White Arc: Is the flaps operating range
- Bottom of White: Stall speed in a landing configuration Vs0
- Top of White: Max flaps extension speed

Green Arc: Normal Operating Range (Vn0)
- Bottom of Green: Stall speed in clean configuration (Vs1)
- Top of Green: Maximum structural cruising speed (Vn0)

Yellow Arc: Caution range. Only operate in smooth air

Red: Never exceed speed (Vne)

Question 4

What are some other speeds not shown on the ASI?

Answer 4

Vx
Vy
Vg
Va

Question 5

How does the ASI work?

Answer 5

• A diaphragm is filled with air through the Pitot tube
• Static air is sensed through the static port
• Dynamic air - Static Air = Airspeed

Question 6

How does the VSI work?

Answer 6

• Aneroid wafer and case are both connected to the static port
• Case has a calibrated leak
• The change in altitude is instantly felt in the wafer and the case
• The delay in the leak from the case indicates the change in altitude until level flight when the pressure is equalized again

Question 7

What are the gyroscopic priniciples?

Answer 7

Gyroscopic Precession

Rigidity in Space

Question 8

What are the gyroscope instruments, and how are they powered?

Answer 8

Attitude Indicator
Heading Indicator
Turn Coordinator

Question 9

How does the Attitude indicator work?

Question 10

What are the errors with the attitude indicator?

Question 11

What are the limitations of the attitude indidcator?

Question 12

How does the DG work?

Question 13

What are the errors with the DG?

Question 14

How does the turn coordinator work?

Question 15

What are it’s errors, and limitations?

Question 16

What is a skidding turn?

Question 17

What is a slipping turn?

Question 18

How does the magnetic compass work?

Question 19

What limitations occurs with the magnetic compass?

Answer 19

Due to how it’s mounted it can tilt up to 18°. During steep bank angles, the compass can indicate erratic and unpredictable errors

Question 20

What are the compass errors?

Question 21

Describe the landing gear of the Cessna?

Answer 21

1. Tricycle type with a steerable nose wheel and 2 main wheels
2. Shock absorption provided by tubular spring steel metal in each main landing gear and air/oil nose gear shock strut
3. Main gear wheel is equipped with a hydraulically actuated brake disc type on the inboard side of each wheel

Question 22

Describe the engine of the C172:

Answer 22

Normally Aspirated
Direct Drive
Air Cooled
Horizontally Opposed
Fuel Injected
Four Cylinder

Rated at 180hp at 2700 RPM

Question 23

Describe how the fuel system works in the C172S:

Answer 23

1. Fuel is gravity fed from the wings
2. Goes to the fuel selector valve
3. Then passes through a fuel reservoir
4. To the fuel pump
5. Passing through the fuel selector valve
6. To the fuel strainer
7. Passing through the engine driven fuel pump
8. To the fuel/air control unit
9. Fuel Distribution valve and here is the fuel flow indicator

Question 24

What is a turbocharger?

Answer 24

• An engine that provides compressed air at higher altitudes so the engine doesn’t starve with the lack of air pressure
• Turbojet engine has a compressor that compresses thinner air powered by the exhaust gasses that powers the turbine

Question 25

What are the different types of propellor?

Answer 25

Cruise Prop: Has a higher AoA which has more drag and lower RPM good for cruising but bad for takeoff and climb performance.

Climb Prop: Has lower AoA, less drag, and higher RPM for more HP during climb and takeoff but lacks efficiency in cruise flight

Question 26

How is the fuel system vented?

Answer 26

1. Through an interconnected line from right tank to the left.
2. The line is vented through the left side below the wing
3. Both filler caps are also vented

Question 27

What’s the purpose of fuel vents?

Answer 27

• As fuel is drawn out from the fuel tank, something must replace the space that is vacated.
• Fuel vents allow air to flow into the tanks to prevent a vacuum happening and starving the engine.

Question 28

What device converts AC current to DC current on the alternator?

Answer 28

• The rectifier blocks the negative charge allowing a DC current to flow all the way through the electrical system

Question 29

Describe the electrical system:

Answer 29

• Runs off a 24 volt battery
• 28V DC current system
• 60amp alternator

Question 30

What’s the difference between Volts and Amps:

Answer 30

• Volts is similar to pressure in a fluid system. It tells us the force between two point.
• Amps is the electric current flowing through the system or the amount/quantity of electron charges flowing through a circuit

Question 31

What are the static wicks purpose?

Answer 31

• To reduce precipitation static that disturbs radio receiver signal

Question 32

Briefly describe the AHSRS, ADC, PFD, MFD, FD, FMS, TAWS systems: