FAA 107 Weather Effects & Flight Planning 4 — Questions and Answers
Question 1: A drone pilot is flying near a large body of water on a sunny afternoon. What local wind effect should they anticipate?
- No wind near water surfaces
- A sea breeze flowing from water toward land (Correct answer)
- A land breeze flowing from land toward water
- Downdrafts directly over the water
Correct answer: A sea breeze flowing from water toward land
On sunny afternoons, land heats faster than water, causing rising air over land that draws in a sea breeze (cool air flowing from water to land).
Question 2: What is 'mountain wave turbulence' and how far downwind can it affect drone operations?
- Turbulence only directly over mountain peaks, extending less than 1 mile
- Turbulence created by wind flowing over mountains, potentially extending 100+ miles downwind (Correct answer)
- Mild turbulence limited to forested areas
- Turbulence that only affects fixed-wing aircraft, not multirotors
Correct answer: Turbulence created by wind flowing over mountains, potentially extending 100+ miles downwind
Mountain wave turbulence is created when wind flows over ridges and can extend hundreds of miles downwind, affecting drone operations far from any mountains.
Question 3: Which cloud type is most associated with thunderstorm activity and should cause a drone pilot to land immediately?
- Cirrus
- Altocumulus
- Cumulonimbus (Correct answer)
- Stratus
Correct answer: Cumulonimbus
Cumulonimbus clouds are the thunderstorm cloud type and produce lightning, severe turbulence, hail, and heavy rain — all immediately dangerous to drone operations.
Question 4: What effect does high altitude (density altitude) have on drone performance?
- Motors run more efficiently due to cooler temperatures
- Reduced air density decreases rotor efficiency and may shorten flight time (Correct answer)
- GPS accuracy improves significantly
- Battery voltage increases at altitude
Correct answer: Reduced air density decreases rotor efficiency and may shorten flight time
At high density altitudes, thinner air reduces rotor efficiency, requiring motors to work harder and consuming more battery power to maintain lift.
Question 5: A pilot observes towering cumulus clouds forming nearby during a flight. What action is most appropriate?
- Continue the mission as cumulus clouds are harmless
- Land immediately as towering cumulus indicate potential thunderstorm development (Correct answer)
- Climb to a higher altitude to avoid the clouds
- Fly toward the clouds to assess their height
Correct answer: Land immediately as towering cumulus indicate potential thunderstorm development
Towering cumulus clouds indicate rapidly developing convective activity that can quickly become thunderstorms with lightning and severe turbulence, requiring immediate landing.
Question 6: What does 'AIRMET Sierra' (AIRMET S) specifically warn pilots about?
- Severe icing above FL200
- IFR conditions and/or mountain obscuration (Correct answer)
- Turbulence below 18,000 feet
- Non-convective low-level wind shear
Correct answer: IFR conditions and/or mountain obscuration
AIRMET Sierra warns of IFR conditions (ceiling below 1,000 feet and/or visibility below 3 miles) and mountain obscuration affecting light aircraft.
Question 7: When is a drone pilot most at risk from 'whiteout' conditions?
- Flying over dark urban areas at night
- Flying over snow-covered terrain with overcast skies that eliminate depth perception (Correct answer)
- Flying in direct sunlight with no clouds
- Flying near large bodies of open water
Correct answer: Flying over snow-covered terrain with overcast skies that eliminate depth perception
Whiteout occurs over snow-covered terrain when overcast skies scatter light uniformly, eliminating shadows and depth perception, making terrain extremely difficult to judge.
FAA 107 Weather Effects & Flight Planning 4
A drone pilot is flying near a large body of water on a sunny afternoon.
What local wind effect should they anticipate?