SIFT SIFT Aviation Weather and Navigation Questions and Answers 2 — Questions and Answers
Question 1: What type of fog forms when warm, moist air flows over a cooler surface, such as a cold ocean current or cold land?
- Radiation fog
- Advection fog (Correct answer)
- Upslope fog
- Steam fog
Correct answer: Advection fog
Advection fog forms when warm, moist air is transported horizontally over a colder surface, cooling the air to its dew point.
Question 2: Which cloud layer is most associated with stable air, smooth flying conditions, and widespread low visibility?
- Cumulus
- Cumulonimbus
- Stratus (Correct answer)
- Cirrocumulus
Correct answer: Stratus
Stratus clouds form in stable air with little vertical motion, often producing overcast skies, drizzle, and reduced visibility without significant turbulence.
Question 3: What is the primary hazard of structural icing on a helicopter's main rotor blades?
- Increased rotor RPM beyond limits
- Disruption of the rotor's airfoil shape, reducing lift and increasing drag (Correct answer)
- Magnetic interference with navigation instruments
- Vibration that locks the anti-torque pedals
Correct answer: Disruption of the rotor's airfoil shape, reducing lift and increasing drag
Ice accumulation distorts the rotor blade's airfoil profile, degrading aerodynamic efficiency and potentially causing asymmetric lift and blade imbalance.
Question 4: In aviation, IMC stands for:
- Instrument Meteorological Conditions (Correct answer)
- Integrated Mission Control
- In-flight Mechanical Checklist
- Indicated Magnetic Course
Correct answer: Instrument Meteorological Conditions
IMC refers to weather conditions below VFR minimums, requiring pilots to fly by instruments rather than outside visual references.
Question 5: High density altitude — such as that experienced on a hot, humid day at a high-elevation airfield — affects helicopter performance by:
- Increasing available engine power and rotor efficiency
- Reducing air density, which decreases both engine power output and rotor lift (Correct answer)
- Increasing rotor lift while reducing engine torque
- Having no measurable effect if the pilot adjusts collective properly
Correct answer: Reducing air density, which decreases both engine power output and rotor lift
High density altitude means thinner air, which reduces the mass of air flowing through the engine and over the rotor blades, decreasing both thrust and power.
Question 6: What does a METAR provide to pilots?
- A 48-hour forecast for a specific airport terminal area
- A routine, standardized report of current surface weather conditions at an airport (Correct answer)
- A graphical depiction of frontal systems across a region
- Pilot reports (PIREPs) of turbulence along airways
Correct answer: A routine, standardized report of current surface weather conditions at an airport
A METAR (Meteorological Terminal Air Report) is an hourly or special observation of actual surface weather — wind, visibility, clouds, temperature, and pressure — at a specific airport.
SIFT SIFT Aviation Weather and Navigation Questions and Answers 2
What type of fog forms when warm, moist air flows over a cooler surface, such as a cold ocean current or cold land?