RPC Weather & Micrometeorology for Drone Operations 3 — Questions and Answers
Question 1: A temperature inversion aloft often creates which flying condition that directly affects drone safety?
- Turbulence at low altitudes
- A stable layer that traps pollution and reduces visibility (Correct answer)
- Strong updrafts above the inversion layer
- Decreased risk of icing
Correct answer: A stable layer that traps pollution and reduces visibility
Temperature inversions trap moisture and pollutants below the inversion base, often resulting in reduced visibility, haze, or smog.
Question 2: Which cloud type is most closely associated with severe turbulence and should prompt a drone pilot to postpone operations?
- Cirrostratus
- Altostratus
- Cumulonimbus (Correct answer)
- Stratocumulus
Correct answer: Cumulonimbus
Cumulonimbus clouds are associated with thunderstorms, lightning, severe turbulence, microbursts, and heavy precipitation—all hazardous to drone operations.
Question 3: The dew point spread (temperature minus dew point) is 2°F. This indicates:
- Very dry air with low fog risk
- Air that is nearly saturated, with high fog or low cloud risk (Correct answer)
- Ideal conditions for drone operations with excellent visibility
- A strong temperature inversion is present
Correct answer: Air that is nearly saturated, with high fog or low cloud risk
A small dew point spread means the air is close to saturation, greatly increasing the likelihood of fog or low cloud formation.
Question 4: Mechanical turbulence near the surface is most likely to occur when:
- Winds are calm and skies are clear
- Strong winds flow over irregular terrain or man-made structures (Correct answer)
- A temperature inversion exists at 500 feet AGL
- Flying over a large body of water
Correct answer: Strong winds flow over irregular terrain or man-made structures
Wind flowing over buildings, trees, hills, and other surface obstacles creates turbulent eddies that can destabilize a drone, especially at low altitudes.
Question 5: A METAR report shows the wind as '00000KT'. What does this mean for a drone pilot?
- Winds are out of the north at 0 knots
- Winds are calm (Correct answer)
- Wind direction is unknown
- Wind observation equipment is offline
Correct answer: Winds are calm
'00000KT' in a METAR denotes calm (no wind), which is favorable for stable drone flight but may still require checking for localized thermal activity.
Question 6: When flying near the ocean coastline, a sea breeze typically develops because:
- Ocean water warms faster than land during the day
- Land heats faster than the ocean, causing air to rise over land and drawing cooler ocean air onshore (Correct answer)
- High pressure systems always form over water in daytime
- Tidal forces push air from sea to land
Correct answer: Land heats faster than the ocean, causing air to rise over land and drawing cooler ocean air onshore
Land heats faster than water during daylight, creating rising thermals over the land that are replaced by cooler, denser air flowing in from the ocean.
Question 7: Which statement best describes why relative humidity increases at night even if no additional moisture is added to the air?
- Dew point temperature rises at night
- Cooler nighttime temperatures bring the air closer to its saturation point (Correct answer)
- Barometric pressure drops and allows more moisture to evaporate
- Wind speeds decrease and trap moisture near the surface
Correct answer: Cooler nighttime temperatures bring the air closer to its saturation point
Relative humidity is the ratio of actual moisture to what the air can hold at that temperature; as temperature drops at night, the air's capacity to hold moisture decreases, so relative humidity rises.
RPC Weather & Micrometeorology for Drone Operations 3
A temperature inversion aloft often creates which flying condition that directly affects drone safety?