FAA ATP Weather Questions

When icing is detected, particularly while operating an aircraft without deicing equipment, the pilot should

• fly to an area with liquid precipitation.
• fly to a lower altitude.
• leave the area of precipitation or go to an altitude where the temperature is above freezing.

Explanation: When icing is detected, a pilot should do one of two things, particularly if the aircraft is not equipped with deicing equipment: leave the area of precipitation or go to an altitude where the temperature is above freezing. This "warmer" altitude may not always be a lower altitude. Proper preflight action includes obtaining information on the freezing level and the above-freezing levels in precipitation areas. A liquid-precipitation area can still produce icing, and a lower altitude isn't reliably warmer.

Aviation Weather - Icing & Hazards

What minimum thickness of cloud layer is indicated if precipitation is reported as light or greater intensity?

• 4,000 feet thick.
• 2,000 feet thick.
• A thickness which allows the cloud tops to be higher than the freezing level.

Explanation: When arriving at or departing from a terminal reporting precipitation of light or greater intensity, expect clouds to be more than 4,000 feet thick. Answer (B) is incorrect because to produce significant precipitation (light or greater intensity), clouds are normally at least 4,000 feet thick. Answer (C) is incorrect because a cloud thickness resulting in cloud tops above the freezing level means ice droplets and supercooled water will develop.

AC 00-6 - Aviation Weather, Precipitation and Cloud Thickness

Weather conditions expected to occur in the vicinity of the airport, but not at the airport, are denoted by the letters 'V(C).' When V(C) appears in a Terminal Aerodrome Forecast, it covers a geographical area of

• a 5 to 10 statute mile radius from the airport.
• a 5-mile radius of the center of a runway complex.
• 10 miles of the station originating the forecast.

Explanation: Proximity applies to weather conditions expected to occur in the vicinity of the airport (between a 5 to 10 mile radius of the airport), but not at the airport itself. It is denoted by the letters 'V(C).'

AC 00-45 - Aviation Weather Services, Terminal Aerodrome Forecast (TAF)

What is the approximate rate unsaturated air will cool flowing upslope?

• 3°C per 1,000 feet.
• 2°C per 1,000 feet.
• 4°C per 1,000 feet.

Explanation: Unsaturated air moving upward and downward cools and warms at about 3.0°C (5.4°F) per 1,000 feet. Answer (B) is incorrect because unsaturated air will cool flowing upslope at 3°C per 1,000 feet. Answer (C) is incorrect because unsaturated air will cool flowing upslope at 3°C per 1,000 feet.

AC 00-6 - Aviation Weather, Adiabatic Process

During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?

• Cumulus.
• Dissipating.
• Mature.

Explanation: Downdrafts characterize the dissipating stage of the thunderstorm. Answer (A) is incorrect because the cumulus stage is the building stage characterized by updrafts. Answer (C) is incorrect because the mature stage has both updrafts and downdrafts, which create strong wind shears.

AC 00-6 - Aviation Weather, Thunderstorm Life Cycle

The prevailing visibility in the following METAR is METAR KFSM 131756Z AUTO 00000KT M1/4SM R25/0600V1000FT -RA FG VV004 06/05 A2989 RMK AO2 $

• less than 1/4 statute mile.
• measured 1/4 statute mile.
• a mean (average) of 1/4 statute mile.

Explanation: The prevailing visibility is less than 1/4 statute miles, indicated by the 'M1/4SM.'

AC 00-45 - Aviation Weather Services, METAR

A severe thunderstorm is one in which the surface wind is

• 58 MPH or greater and/or surface hail is 3/4 inch or more in diameter.
• 50 knots or greater and/or surface hail is 1/2 inch or more in diameter.
• 45 knots or greater and/or surface hail is 1 inch or more in diameter.

Explanation: A severe thunderstorm is one which has surface winds of 50 knots (58 MPH) or more, and/or has hail 3/4 inch or more in diameter.

AC 00-6 - Aviation Weather, Thunderstorms

The most likely condition in which to experience severe inflight icing with the ambient temperature below 0 degrees C is

• rain.
• visible moisture.
• fog.

Explanation: For structural icing to occur two conditions must be present: The aircraft must be flying through visible water such as rain or cloud droplets and temperature at the point where the moisture strikes the aircraft must be 0 degrees or colder.

AC 00-6 - Aviation Weather, Structural Icing