Weather and Minimums

Question 1

VFR minimums for surface based class E airspace

Answer 1

1,000’ ceilings and 3 statute miles visibility

Question 2

Steam fog

Answer 2

Also known as sea smoke fog, forms when cold, dry air moves over warm water.

It’s most common over bodies of water during the coldest times of year.

Low level turbulence and icing are commonly associated with steam fog.

Question 3

Upslope fog

Answer 3

Occurs when moist, stable air is forced up slipping land features like a mountain range. Wind is required to form.

Question 4

Advection fog

Answer 4

Common in coastal areas where sea breeze can blow the air over cooler land masses. Wind required to form, up to 15 knots.

Question 5

Radiation fog

Answer 5

When there is little to no wind present on a clear night. Usually forms in low-lying areas like mountain valleys.

Question 6

The lifespan of a microburst is about 5-15 mins during which time it can produce downdrafts of up to ________ fpm and headwind losses of ________ knots.

Answer 6

6,000 fpm; 30-90 knots

Question 7

Low level wind shear is commonly associated with?

Answer 7

Passing frontal systems, thunderstorms, temperature inversions, and strong upper level winds (greater than 25 knots)

Question 8

Convective currents cause the bumpy, turbulent air sometimes experienced when flying at lower altitudes during warmer weather. Typically, these conditions can be avoided by?

Answer 8

Flying at higher altitudes, even able a cumulus cloud layer.

Question 9

Updrafts are likely to occur where?

Answer 9

Over pavement or barren places

Question 10

Downdrafts are likely to occur over where?

Answer 10

Water or expansive areas of vegetation like a group of trees.

Question 11

Convective currents can occur anywhere there is?

Answer 11

An uneven hearing of the earths surface

Question 12

The reactions of the average person become impaired at an altitude of about?

Answer 12

10,000 feet

Question 13

On average, with every 1,000 feet of increase in altitude, the atmospheric pressure decreases by?

Answer 13

1” Hg (1 inch of mercury)

Question 14

Visible moisture will form when

Answer 14

Temperature and dew point are equal

Question 15

Generally, the wind 2,000’ AGL ___________ degrees to the right of surface winds , and the speed is greater.

Answer 15

20 to 40 degrees

Question 16

Clouds type is determined by?

Answer 16

It’s height, shape, and characteristics

Question 17

Low clouds

Answer 17

• Form near the earths surface and up to about 6,500 AGL
• Can include supercooled water droplets that include hazardous aircraft icing
• Typical los clouds are stratus, stratocumulus, and nimbostratus

Question 18

Middle clouds

Answer 18

• Range in heights from around 6,500 AGL and extend up to 20,000 AGL
• Include altostratus and altocumulus clouds
• Altostratus clouds can produce turbulence and may contain moderate icing. Altostratus, form when altostratus is breaking about can produce the same.

Question 19

High clouds

Answer 19

• Form above 20,000 AGL and usually form in stable air only.
• Made up of ice crystals and pose no real threat of turbulence or aircraft icing.
• Typical high level clouds are cirrus, cirrostratus, and cirrocumulus.

Question 20

Cumulonimbus clouds

Answer 20

• Dangerous
• Appears individually or in groups
• indicate areas of instability

Question 21

Warm fronts

Answer 21

• Move slowly, typically 10-25 mph

* Light to moderate precipitation is probable with nimbostratus cloud formation.

Question 22

Cold fronts

Answer 22

• Move at a rate of 25-30 MPH, but extreme ones can move faster
• Create cumulonimbus clouds along the line of the front

Question 23

Thunderstorms stages

Answer 23

1. Cumulus stage; lifting action of the air begins.
2. Mature stage; most violent time period. Drops of moisture become too heavy for the cloud to support and begin falling in the form of rain or hail.
3. Diss a pairing stage; vertical motion near the top of the cloud slows, and the top of the cloud takes an anvil-like shape. Downdrafts spread out and replace the updrafts needed to sustain the storm.

Question 24

Ingredients of a thunderstorm

Answer 24

Air must have sufficient water vapor, an unstable lapse rate, and an initial lifting action.

Question 25

Lapse rate

Answer 25

Rate of vertical temperature change. The steeper the lapse rate, the more unstable the atmosphere becomes.

Question 26

Class G airspace minimums

Answer 26

1 mile and clear of clouds

Question 27

Controlled airspace VFR (Class E, C, B, D)

Answer 27

3 miles visibility, 500ft below clouds, 1,000ft above clouds, and 2,000ft vertical separation