PPL Aeronautical Knowledge 3 — Questions and Answers
Question 1: What does a red arc on an airspeed indicator represent?
- Normal operating range
- Flap operating range
- Never-exceed speed (VNE) (Correct answer)
- Caution range
Correct answer: Never-exceed speed (VNE)
The red line marks VNE, the never-exceed speed.
Question 2: The white arc on the airspeed indicator represents the:
- Normal operating range
- Flap operating range (Correct answer)
- Caution range
- Never-exceed range
Correct answer: Flap operating range
The white arc is the flap operating range, from VS0 to VFE.
Question 3: Which instrument operates on the pitot-static system alone?
- Attitude indicator
- Heading indicator
- Airspeed indicator (Correct answer)
- Turn coordinator
Correct answer: Airspeed indicator
The airspeed indicator uses both pitot (ram) and static pressure.
Question 4: If the pitot tube becomes blocked but the static port remains clear, the airspeed indicator will:
- Read zero
- Act like an altimeter during climbs and descents (Correct answer)
- Read correctly
- Freeze at current value only in level flight
Correct answer: Act like an altimeter during climbs and descents
A blocked pitot tube with a clear static port makes the airspeed indicator behave like an altimeter.
Question 5: The attitude indicator, heading indicator, and turn coordinator most commonly rely on:
- Pitot pressure
- Gyroscopic principles (Correct answer)
- Static pressure
- Magnetic fields
Correct answer: Gyroscopic principles
These are gyroscopic instruments driven by rigidity in space and precession.
Question 6: During which condition does the magnetic compass read most accurately?
- During acceleration on an easterly heading
- During a turn
- In straight-and-level, unaccelerated flight (Correct answer)
- During a climb on a northerly heading
Correct answer: In straight-and-level, unaccelerated flight
The magnetic compass is accurate only in straight-and-level, unaccelerated flight.
Question 7: What error occurs when accelerating on an east or west heading (in the Northern Hemisphere)?
- The compass shows a turn to the north (Correct answer)
- The compass shows a turn to the south
- The compass lags behind
- No error occurs
Correct answer: The compass shows a turn to the north
Acceleration on east/west headings causes the compass to indicate a turn toward north (remember ANDS).
PPL Aeronautical Knowledge 3
What does a red arc on an airspeed indicator represent?