Weather Information practice questions

Answer: C) 3 hours

G-AIRMETs are issued every 6 hours for the contiguous U.S. Each issuance shows snapshots valid at discrete times no more than 3 hours apart, covering up to 12 hours.

• AIncorrect. Six hours is how often CONUS G-AIRMETs are issued on their regular schedule. It is not the spacing between the snapshots inside one issuance.
• BIncorrect. G-AIRMET snapshots are not hourly. They are valid at discrete times up to 3 hours apart.
• CCorrect. G-AIRMET snapshots are valid at discrete times no more than 3 hours apart (for example 00, 03, 06, 09 and 12 hours). Pilots should assume a hazard exists between snapshots unless told otherwise.
• DIncorrect. Twelve hours is the total forecast period one G-AIRMET issuance covers, not the spacing between its snapshots.

Answer: B) BKN, OVC or VV

• AIncorrect. These are not ceilings.
• BCorrect. Broken, overcast or vertical visibility define a ceiling.
• CIncorrect. Only BKN, OVC or VV.
• DIncorrect. It is the lowest qualifying layer.

Answer: C) 3,000 feet above the tops

The AIM says to clear the top of a known or suspected severe thunderstorm by at least 1,000 ft for each 10 knots of wind at the cloud top. With 30 knots, that is at least 3,000 ft.

• AIncorrect. This ignores the wind at the tops. The guidance scales clearance with wind speed: 1,000 ft for each 10 knots.
• BIncorrect. This uses 500 ft per 10 knots, which is half the recommended clearance.
• CCorrect. The AIM recommends clearing severe thunderstorm tops by at least 1,000 ft for each 10 knots of wind at the cloud top. 30 knots ÷ 10 × 1,000 ft = 3,000 ft.
• DIncorrect. This uses 2,000 ft per 10 knots, which is double the AIM figure.

Answer: C) 0°C to −15°C

• AIncorrect. Clouds are mostly ice crystals here.
• BIncorrect. Water does not freeze on the airframe here.
• CCorrect. Supercooled liquid water is most common in this range.
• DIncorrect. Little liquid water exists.

Answer: B) An obscured sky, 500 ft

• AIncorrect. VV is vertical visibility.
• BCorrect. VV is vertical visibility into an indefinite ceiling, here 500 feet.
• CIncorrect. This is not wind.
• DIncorrect. That is OVC050.

Answer: D) Extending the flaps toward the landing setting on approach

An iced tailplane is most likely to stall when the flaps are extended, because the added downwash raises the tail's negative angle of attack. Retracting the flaps to the previous setting is part of the recovery.

• AIncorrect. Retracting flaps reduces downwash on the tail and lowers its negative angle of attack. Retracting flaps to the previous setting is part of the recovery from a tailplane stall, not the cause of one.
• BIncorrect. That risks a wing stall. Tailplane stall is linked to flap extension, often at higher airspeeds, where the tail's negative angle of attack is greatest.
• CIncorrect. Removing ice from the wing does not change the angle of attack of the horizontal tail, so it is not a typical trigger.
• DCorrect. Extending flaps increases downwash and the tail's negative angle of attack. That can stall an ice-contaminated stabilizer, which collects ice more efficiently than the wing.

Answer: B) A blue line with triangles toward the warmer air

Cold fronts are drawn as blue lines with triangles pointing in the direction of movement, toward the warmer air. Warm fronts use red semicircles and occluded fronts use purple with both symbols.

• AIncorrect. A red line with semicircles (rounded barbs) pointing in the direction of movement is the warm front symbol.
• BCorrect. A cold front is a blue line with triangles (pointed barbs) pointing in the direction the front moves, which is toward the warmer air it is replacing.
• CIncorrect. A purple line with alternating triangles and semicircles is the occluded front symbol.
• DIncorrect. A dashed line with no frontal symbols marks a trough, not a front.

Answer: C) Persist while wind keeps pushing moist air uphill

• AIncorrect. Upslope fog can persist.
• BIncorrect. That isn't upslope fog.
• CCorrect. It can cover large areas.
• DIncorrect. It forms as air is lifted up slopes.

Answer: A) Turbulence and wind shear beneath the storms can be severe, even where the air below looks calm

FAA thunderstorm guidance says never to fly under a thunderstorm or squall line, even if you can see through to the other side, because severe turbulence and wind shear beneath the storms can be hazardous.

• ACorrect. The AIM says not to fly under a thunderstorm even if you can see through to the other side, because turbulence and wind shear under the storm could be hazardous. Strong outflow winds and downdrafts below the bases can cause severe turbulence.
• BIncorrect. A squall line is a band of active thunderstorms in unstable air. The air beneath it is not stable, and downdrafts and outflow make it turbulent.
• CIncorrect. Turbulence in thunderstorms is not limited to the tops. FAA guidance warns that turbulence beneath a thunderstorm should not be minimized, and severe turbulence and wind shear can occur below the cloud base.
• DIncorrect. Precipitation static can degrade communication and navigation reception, but it is not why pilots are told to stay out from under thunderstorms. The main danger is turbulence and wind shear.

Answer: A) Negative, unsigned

• ACorrect. Above 24,000 feet the minus sign is omitted because temperatures are always below zero.
• BIncorrect. They are negative.
• CIncorrect. They are Celsius.
• DIncorrect. They are forecast.