PPL PPL Flight Instruments and Weather 1 — Questions and Answers
Question 1: What does the altimeter measure and what errors can affect its accuracy?
- Atmospheric pressure to indicate altitude; errors include non-standard temperature, pressure setting errors, and instrument lag (Correct answer)
- Ground speed only
- Wind direction
- Engine performance
Correct answer: Atmospheric pressure to indicate altitude; errors include non-standard temperature, pressure setting errors, and instrument lag
The altimeter measures atmospheric pressure and converts it to altitude indication. Errors include incorrect pressure setting (altimeter setting), non-standard temperatures (cold: lower than indicated), and instrument lag during rapid altitude changes.
Question 2: What are the minimum weather requirements for VFR flight in Class G airspace below 1,200 feet AGL during the day?
- 1 statute mile visibility and clear of clouds (Correct answer)
- 3 statute miles visibility and 500 feet below clouds
- 5 statute miles visibility
- No weather minimums in Class G
Correct answer: 1 statute mile visibility and clear of clouds
In Class G airspace below 1,200 feet AGL during the day, VFR minimums are 1 statute mile flight visibility with clear of clouds requirement, the least restrictive VFR weather minimums.
Question 3: What causes a stall in an aircraft?
- Exceeding the critical angle of attack, disrupting airflow over the wing — this can occur at any airspeed and attitude (Correct answer)
- Flying too slowly
- Engine failure
- Running out of fuel
Correct answer: Exceeding the critical angle of attack, disrupting airflow over the wing — this can occur at any airspeed and attitude
A stall occurs when the wing exceeds its critical angle of attack (typically 16-20°), causing airflow separation over the upper surface and loss of lift. It can occur at any airspeed, attitude, or power setting.
Question 4: What is the magnetic compass's turning errors?
- In the Northern Hemisphere: leads on turns from N, lags on turns from S (UNOS: Undershoot North, Overshoot South) (Correct answer)
- The compass has no errors
- Errors only occur above 10,000 feet
- The compass only works while flying straight
Correct answer: In the Northern Hemisphere: leads on turns from N, lags on turns from S (UNOS: Undershoot North, Overshoot South)
Due to the Earth's magnetic field dip, the compass leads (indicates a turn before it occurs) when turning from northerly headings and lags when turning from southerly headings in the Northern Hemisphere.
Question 5: What information is provided in a METAR weather report?
- Station, time, wind, visibility, weather phenomena, sky conditions, temperature/dewpoint, and altimeter setting (Correct answer)
- Only temperature and wind
- Just visibility conditions
- Only precipitation type
Correct answer: Station, time, wind, visibility, weather phenomena, sky conditions, temperature/dewpoint, and altimeter setting
METAR reports include station identifier, observation time, wind direction/speed/gusts, visibility, present weather phenomena, sky condition (cloud layers), temperature and dewpoint, altimeter setting, and remarks.
Question 6: What is the purpose of a flight plan?
- To provide search and rescue notification if the flight is overdue, and to communicate intended route and timing to ATC/FSS (Correct answer)
- It is a legal requirement for all flights
- To request special airspace access only
- To book a parking space at the destination
Correct answer: To provide search and rescue notification if the flight is overdue, and to communicate intended route and timing to ATC/FSS
A VFR flight plan alerts search and rescue services if you become overdue, providing your route, aircraft description, fuel endurance, and expected arrival time. It is recommended but not legally required for most VFR flights.
PPL PPL Flight Instruments and Weather 1
What does the altimeter measure and what errors can affect its accuracy?