A2 CofC Meteorology for UAS Operations 2 — Questions and Answers
Question 1: What type of weather front typically brings sudden changes in wind direction and speed that could affect drone operations?
- A warm front with gradual changes
- A cold front with rapid weather changes including gusting winds and possible thunderstorms (Correct answer)
- A stationary front with no wind changes
- An occluded front which only affects high-altitude weather
Correct answer: A cold front with rapid weather changes including gusting winds and possible thunderstorms
Cold fronts move faster than warm fronts and are associated with rapid weather changes including sudden wind shifts, gusting winds, heavy rain showers, and possible thunderstorms. These conditions can develop quickly and catch unprepared drone operators off guard.
Question 2: What is wind shear and why is it dangerous for drone operations?
- A steady increase in wind speed over time
- A sudden change in wind speed and/or direction over a short distance, which can cause loss of control (Correct answer)
- The difference between wind speed at ground level and at altitude — it has no effect on drones
- A type of wind that only occurs over water
Correct answer: A sudden change in wind speed and/or direction over a short distance, which can cause loss of control
Wind shear is a rapid change in wind velocity (speed and/or direction) over a short distance. It commonly occurs near buildings, trees, and terrain features. For drones, wind shear can cause sudden unexpected movements, loss of GPS-assisted hovering accuracy, and in severe cases, complete loss of control.
Question 3: During which season are UK drone pilots most likely to encounter reduced visibility due to radiation fog?
- Summer
- Autumn and winter (Correct answer)
- Spring
- Fog occurs equally in all seasons
Correct answer: Autumn and winter
Radiation fog forms during clear, calm nights when the ground cools rapidly and chills the air above it to its dew point. This is most common in autumn and winter in the UK when nights are long and temperatures drop quickly, often persisting into the morning.
Question 4: How does flying in rain affect drone performance and safety?
- Modern drones are fully waterproof so rain has no effect
- Rain can affect GPS signal, reduce visibility, add weight to the drone, and cause electrical damage to non-waterproof components (Correct answer)
- Rain only affects the camera image quality
- Rain improves cooling and extends flight time
Correct answer: Rain can affect GPS signal, reduce visibility, add weight to the drone, and cause electrical damage to non-waterproof components
Rain poses multiple risks: water ingress can damage electronics and motors; water on propellers changes their aerodynamic profile; reduced visibility may compromise VLOS; rain can interfere with optical sensors; and added water weight increases power consumption. Most consumer drones are not waterproof.
Question 5: What is a METAR and how can it be useful for drone pilots planning a flight?
- A type of drone maintenance report
- A coded aviation weather report for a specific aerodrome, providing current conditions including wind, visibility, cloud base, and temperature (Correct answer)
- A forecast for weather 24 hours ahead
- A measurement of electromagnetic interference
Correct answer: A coded aviation weather report for a specific aerodrome, providing current conditions including wind, visibility, cloud base, and temperature
A METAR (Meteorological Aerodrome Report) provides current observed weather conditions at an aerodrome, including wind speed and direction, visibility, cloud cover and height, temperature, dew point, and pressure. Drone pilots can use METARs from nearby aerodromes to assess current conditions.
Question 6: At what visibility level should a drone pilot seriously consider cancelling or postponing an Open category flight?
- Below 10 km
- Below 5 km
- When visibility is reducing and the pilot can no longer confidently maintain VLOS with the drone at its intended operating distance (Correct answer)
- Below 1 km
Correct answer: When visibility is reducing and the pilot can no longer confidently maintain VLOS with the drone at its intended operating distance
There is no specific regulatory minimum visibility for Open category drone flights, but the pilot must maintain VLOS at all times. The practical limit depends on the drone's size, colour, and lighting, as well as the background conditions. If the pilot cannot reliably see the drone, the flight must not continue.
A2 CofC Meteorology for UAS Operations 2
What type of weather front typically brings sudden changes in wind direction and speed that could affect drone operations?