SIFT Aviation Weather and Navigation Questions and Answers Flashcards

What type of fog forms when warm, moist air flows over a cooler surface, such as a cold ocean current or cold land?

Answer: Advection fog

Advection fog forms when warm, moist air is transported horizontally over a colder surface, cooling the air to its dew point.

Which cloud layer is most associated with stable air, smooth flying conditions, and widespread low visibility?

Answer: Stratus

Stratus clouds form in stable air with little vertical motion, often producing overcast skies, drizzle, and reduced visibility without significant turbulence.

What is the primary hazard of structural icing on a helicopter's main rotor blades?

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.

In aviation, IMC stands for:

Answer: Instrument Meteorological Conditions

IMC refers to weather conditions below VFR minimums, requiring pilots to fly by instruments rather than outside visual references.

High density altitude — such as that experienced on a hot, humid day at a high-elevation airfield — affects helicopter performance by:

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.

What does a METAR provide to pilots?

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.