Weather

Question 1

What is wind shear?

Answer 1

An abrupt change in wind speed or direction.

Question 2

What is a microburst?

Answer 2

A typical microburst is a downdraft that may emerge from a cloud (or no cloud) as high as 15,000 feet.

Question 3

Describe the potential outcome of encountering a microburst during takeoff?

Answer 3

The aircraft may encounter a headwind at liftoff, followed by a decreasing headwind, immediately followed by a strong downdraft and an extreme tailwind that may be beyond the performance capability of the aircraft to recover from prior to impact.

Question 4

What are some thunderstorm avoidance procedures?

Answer 4

1. Maintain VFR conditions ON TOP as long as possible so as to observe and avoid build-ups.
2. Maintain VFR conditions below the bases so as to observe and avoid rain shafts. However, never fly directly below a cell.
3. Day - Do NOT go where the sky is dark.
4. Night - Do NOT go where the lightning is.

Question 5

What are the three stages of a thunderstorm?

Answer 5

1. Cumulus
2. Mature
3. Dissipating

Question 6

How many miles should you avoid a thunderstorm?

Answer 6

20 Miles

Question 7

What are some things you should do if you penetrate a thunderstorm?

Answer 7

1. Be as low as possible
2. Tighten seat belts
3. Cockpit lights to highest intensity
4. Slow down to Va
5. Tell ATC what you are doing
6. Keep the wings level and airspeed somewhere close to Va (do not chase altitude or airspeed).

Question 8

Where is ice usually found?

Answer 8

VISIBLE moisture between 5 & -20 degrees celsius or colder, but usually between 2 & -10 degrees.

Question 9

What are “known icing conditions”?

Answer 9

“Known icing conditions” exist when a pilot knows or reasonably should know about weather reports in which icing conditions are reported or forecast.

Question 10

Should you takeoff with frost on the airframe?

Answer 10

No. Take off “clean” without any ice, snow, or frost on the aircraft.

Question 11

How should you avoid icing?

Answer 11

Find out what the freezing level is, stay 3000 feet below it or 8000 feet above it, or above the clouds.

Question 12

What should you do if you encounter icing?

Answer 12

1. Gently turn around and run away (safest tactic).
2. Climbing is usually the preferred first option. You’ll either break out on top or climb into air too cold for icing.
3. Descending is the usually preferred second option.

Question 13

Why does carburetor ice occur?

Answer 13

It occurs due to the effect of fuel vaporization and the decrease in air pressure in the Venturi which causes a sharp temperature drop in the carburetor. Under the proper conditions this can cause the water vapor in the air to condense and freeze which can restrict the fuel/air mixture or even block it completely.

Question 14

What are the three types of ice?

Answer 14

1. Rime Ice
2. Clear Ice
3. Mixed Ice

Question 15

What is rime ice?

Answer 15

A collection of very small, supercooled water droplets that freeze on contact (most common type). It is milky or opaque appearance due to air bubbles that become trapped between the frozen droplets. Usually associated with stratus clouds.

Question 16

What is clear ice?

Answer 16

A collection of large, close to freezing water droplets that flow back across the wing before freezing. Clear ice is hard, glossy, extremely heavy, and very difficult to dislodge. Usually associated with large cumulus clouds and turbulence.

Question 17

What are the four levels of icing?

Answer 17

1. Trace
2. Light
3. Moderate
4. Severe

Question 18

Describe trace icing.

Answer 18

Ice becomes barely perceptible, rate of accumulation is slightly greater than sublimation.

Question 19

Describe light icing.

Answer 19

May be a problem if the flight is prolonged (over 1 hour), occasional use of deice/anti-ice removes accumulation. Does not present a problem if deice/anti-ice equipment is used.

Question 20

Describe moderate icing.

Answer 20

Even short encounters become potentially hazardous, use of deice/anti-ice or flight diversion is necessary.

Question 21

Describe severe icing.

Answer 21

The rate of accumulation is such that deice/anti-ice equipment fails to reduce or control the hazard. Immediate flight diversion is necessary.

Question 22

What is a jet stream?

Answer 22

A migrating high-velocity narrow stream of winds meandering around the globe in a wavelike pattern at high altitudes, usually found near the upper limit of the troposphere, which flows generally from west to east.

Question 23

What is an AWOS?

Answer 23

Automated Weather Observing System. A suite of weather sensors of many different configurations that were either procured by the FAA or purchased by individuals, groups or airports that are required to meet FAA standards.

Question 24

What does A01 mean?

Answer 24

Indicates a station WITHOUT a precipitation identification sensor.

Question 25

What does A02 mean?

Answer 25

Indicates a station WITH a precipitation identification sensor.

Question 26

What is an ASOS?

Answer 26

1. Automated Surface Observation System. More sophisticated than AWOS and is designed to provide the necessary information to generate weather forecasts.
2. Continual minute-by-minute observations necessary to generate a routine weather report (METAR).
3. Can generate weather forecasts (TAF).
4. Can determine type and intensity of precipitation, thunderstorms, and obstructions to visibility such as haze or fog.

Question 27

What is a METAR?

Answer 27

1. Aviation Routine Weather Report
2. Terminal weather OBSERVATIONS.
3. Normally this will be an hourly surface weather observation issued 5 minutes before each hour.
4. SPECI - is a special (METAR) report issued because of quickly changing conditions.

Question 28

What is a TAF?

Answer 28

1. Terminal Aerodrome Forecast.
2. Detailed 24-hour FORECAST normally issued four times a day starting at approximately 30 minutes before each main synoptic hour (00Z, 06Z, 12Z, 18Z) of PREDICTED weather conditions expected to occur within a 5 SM radius of an airport.
3. Some airports have 30 hour TAF.

Question 29

What is a ceiling?

Answer 29

Height above the earth’s surface (AGL) of the lowest layer of clouds or obscuring phenomena reported as “broken”, “overcast”, or “obscuration”, and not classified as “thin” or “partial.” Clouds are reported as broken when 5/8 - 7/8 of the sky is covered. Overcast means entire sky.