PPL PPL Flight Instruments and Weather 2 — Questions and Answers
Question 1: Which instrument relies on the pitot tube's ram air pressure to operate?
- Airspeed indicator (Correct answer)
- Altimeter
- Vertical speed indicator
- Heading indicator
Correct answer: Airspeed indicator
The airspeed indicator measures the difference between ram (pitot) pressure and static pressure.
Question 2: If the static port becomes blocked in level flight, which instruments will be affected?
- Airspeed, altimeter, and vertical speed indicator (Correct answer)
- Only the altimeter
- Attitude indicator and turn coordinator
- Magnetic compass only
Correct answer: Airspeed, altimeter, and vertical speed indicator
The airspeed indicator, altimeter, and VSI all use the static system, so a static blockage affects all three.
Question 3: The attitude indicator, heading indicator, and turn coordinator are typically driven by what system in many training aircraft?
- Vacuum (gyroscopic) system (Correct answer)
- Pitot-static system
- Electrical pitot heat
- Magnetic field only
Correct answer: Vacuum (gyroscopic) system
These gyroscopic instruments are commonly powered by an engine-driven vacuum pump.
Question 4: During a coordinated turn, where should the ball in the turn coordinator be positioned?
- Centered (Correct answer)
- To the inside of the turn
- To the outside of the turn
- Fully deflected left
Correct answer: Centered
A centered ball indicates coordinated flight with the correct balance of bank and rudder.
Question 5: What altitude does the altimeter display when set to the local altimeter setting on the ground?
- Field elevation (Correct answer)
- Pressure altitude
- Density altitude
- Zero
Correct answer: Field elevation
With the current local setting, the altimeter should read the airport's field elevation.
Question 6: A pilot notices the airspeed reads zero shortly after takeoff while other instruments are normal. What is the most likely cause?
- Blocked pitot tube (Correct answer)
- Blocked static port
- Vacuum pump failure
- Discharged battery
Correct answer: Blocked pitot tube
A blocked pitot ram-air inlet causes the airspeed indicator to read low or zero.
Question 7: The magnetic compass exhibits errors during turns; the acronym 'UNOS' refers to which error?
- Undershoot North, Overshoot South (Correct answer)
- Overshoot North, Undershoot South
- Turning error on east/west
- Acceleration on north/south
Correct answer: Undershoot North, Overshoot South
In the Northern Hemisphere the compass undershoots when turning to north and overshoots when turning to south.
PPL PPL Flight Instruments and Weather 2
Which instrument relies on the pitot tube's ram air pressure to operate?