RPC Weather & Micrometeorology for Drone Operations 2 — Questions and Answers
Question 1: What weather phenomenon is most likely to cause a drone to experience a sudden, uncommanded descent during flight?
- Radiation fog
- Microburst downdraft (Correct answer)
- Ground effect
- Temperature inversion
Correct answer: Microburst downdraft
A microburst produces intense localized downdrafts that can exceed a drone's climb capability, causing sudden uncommanded descent.
Question 2: On a clear night with calm winds, which type of fog is most likely to develop in low-lying areas and river valleys by early morning?
- Steam fog
- Advection fog
- Radiation fog (Correct answer)
- Frontal fog
Correct answer: Radiation fog
Radiation fog forms on clear, calm nights when the ground radiates heat away and cools the air near the surface below the dew point.
Question 3: What is the primary reason surface winds are typically lighter and more variable at sunrise compared to mid-afternoon?
- Higher pressure gradients at night
- Less convective mixing to bring down faster upper-level winds (Correct answer)
- Increased Coriolis effect in morning hours
- Frontal boundaries are closer to the surface at dawn
Correct answer: Less convective mixing to bring down faster upper-level winds
Daytime solar heating creates convective mixing that transports momentum from faster winds aloft down to the surface, strengthening surface winds.
Question 4: A drone remote pilot notices cumulus clouds building rapidly in the late afternoon. This development most likely indicates:
- Stable air with improving visibility
- Increasing convective activity and possible thunderstorm development (Correct answer)
- A weakening temperature inversion
- Improving conditions for sUAS operations
Correct answer: Increasing convective activity and possible thunderstorm development
Rapidly growing cumulus clouds in the afternoon signal strong thermal uplift and convective instability, precursors to thunderstorm development.
Question 5: Which wind shear scenario poses the greatest hazard to a small drone operating at 200 feet AGL?
- Gradual increase of 5 knots per 1,000 feet
- Abrupt change of 25 knots within 200 feet of altitude (Correct answer)
- Steady 15-knot headwind at cruise altitude
- 10-knot crosswind at a constant altitude
Correct answer: Abrupt change of 25 knots within 200 feet of altitude
An abrupt large change in wind speed or direction within a short altitude band creates severe shear that can instantly overpower a small drone's control authority.
Question 6: Density altitude is defined as pressure altitude corrected for:
- Wind speed and direction
- Non-standard temperature (Correct answer)
- Relative humidity only
- Magnetic variation
Correct answer: Non-standard temperature
Density altitude equals pressure altitude adjusted for temperature deviations from the standard atmosphere, which affects aircraft/drone performance.
Question 7: A remote pilot planning a flight in a desert location on a hot summer afternoon should expect which primary performance impact on the drone?
- Increased lift due to denser air
- Reduced lift and longer battery drain due to high density altitude (Correct answer)
- More responsive controls due to thinner air
- Stronger GPS signal due to clear skies
Correct answer: Reduced lift and longer battery drain due to high density altitude
High density altitude (hot, high, humid conditions) means thinner air, so propellers generate less thrust and the drone's motors must work harder, draining batteries faster.
RPC Weather & Micrometeorology for Drone Operations 2
What weather phenomenon is most likely to cause a drone to experience a sudden, uncommanded descent during flight?