Weather Midterm 1

Dispatch Fundamentals

When you hear a SIGMET on an ATC frequency forecasting severe icing conditions on the route to your destination, you plan for

 

the possibility of freezing rain and freezing drizzle that can accumulate on and beyond the limits of any deicing/anti-icing equipment

What sources reflect the most accurate information on current and forecast icing conditions?

 

AIRMET Zulus

Which INITIAL cockpit indications should a pilot ALL be aware of when a constant tailwind shears to a calm wind?

 

AItitude, pitch, and indicated airspeed increase

Anti-icing fluid should provide freezing point protection to

 

a freezing point no greater than 20°F below the ambient or aeroplane surface temperature

Which type clouds are indicative of very strong turbulence?

 

Standing lenticular

Which arctic flying hazard is caused when a cloud layer of uniform thickness overlies a snow or ice covered surface?

Whiteout

Which primary source contains information regarding the expected
weather at the destination airport, at the ETA?

 

Terminal Aerodrome Forecast

Atmospheric pressure changes due to a thunderstorm will be at the lowest value

 

when the thunderstorm is approaching

What is the primary cause of all changes in the Earth's weather?

 

Variations of solar energy at the earth's surface.

The stability of an air mass can usually be determined by

 

cloud types and the type of precipitation

What weather is predicted by the term VCTS in a Terminal Aerodrome Forecast?

 

Thunderstorms are expected in the vicinity

Turbulence encountered above 15,000 feet AGL, not associated with cloud formations, should be reported as

 

clear air turbulence

Which conditions are necessary for the formation of upslope fog?

 

Moist, stable air being moved over gradually rising ground by a wind

Jetstreams are strongest during which season in the Northern Hemisphere?

Winter

At which location does Coriolis force have the least effect on wind direction?

At the Equator

Which process causes adiabatic cooling?

 

Expansion of air as it rises

Isobars on a surface weather chart represent lines of equal pressure

 

reduced to sea level

SPECI KGLS 131802Z 10012G21KT 060V140 2SM +SHRA SCT005 BKN035 OVC050CB 24/23 A2980 RMK RAB1757 WS TKO RWO9L WSHFT 58 FROPA.

This SPECI report at Galveston (KGLS) indicates which condition?

 

Precipitation started at 1757

What course of action should the pilot take if encountering freezing rain?

 

Climb because the temperature is warmer at a higher altitude

Even a small amount of frost, ice, or snow may

 

hinder lift production to a point where takeoff will be impossible

If a SIGMET alert is announced, how can information contained in the SIGMET be obtained? 

 

By contacting the nearest flight service

Which action is recommended if jetstream turbulence is encountered with a direct headwind or tailwind?

 

Change altitude or course to avoid a possible elongated turbulent area

You are planning to arrive at the KHOU airport at 0900Z, what conditions can be expected as indicated by this TAF:
KHOU 151720Z 1518/1618 22009KT P6SM SCT030 SCT250
FM160000 18005KT P6SM BKN050 BKN120 FM160600 21007KT P6SM VCSH SCT025 BKN200
FM160900 34010KT P6SM VCTS BKN035CB BKN250
TEMPO 1611/1613 TSRA BKN012 OVC025CB
FM161600 35007KT P6SM BKN020

 

Thunderstorm activity 5 to 10 miles from the airport's runway complex

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

 

leave the area of precipitation or go to an altitude where the temperature is above freezing

The threshold wind speed in the jet stream for clear air turbulence is generally considered to be

110 kts

Precipitation induced fog

 

results from relatively warm rain or drizzle falling through cooler air

Which initial cockpit indications should a pilot be aware of when a constant headwind shears to a calm wind?

 

Altitude pitch, and indicated airspeed decrease

What weather difference is found on each side of a "dry line?"

Dewpoint difference

Freezing Point Depressant (FPD) fluid residue on engine fan or compressor blades

 

can reduce engine performance and cause surging and/or compressor stalls

Where do the maximum winds associated with the jetstream usually occur?

 

In the vicinity of breaks in the tropopause on the polar side of the jet core

Where is the normal location of the jetstream relative to surface lows and fronts?

 

The jetstream is located north of the surface systems

Which area or areas of the Northern Hemisphere experience a generally east to west movement of weather systems?

 

Artic and subtropical

Which type clouds may be associated with the jetstream?

 

Cirrus clouds on the equatorial side of the jetstream

Frozen dew is

 

hard and transparent

Thrust is being managed to maintain desired indicated airspeed and the glide slope is being flown. Which characteristics should be observed when a tailwind shears to a constant headwind?

PITCH ATTITUDE: Increases. VERTICAL SPEED: Decreases. INDICATED AIRSPEED: Increases, then decreases

Which is a disadvantage of the one-step over the two-step process when deicing/anti-icing an aeroplane?

 

More fluid is used with the one-step method when large deposits of ice and snow must be flushed off aeroplane surfaces

The purpose of diluting ethylene glycol deicing fluid with water in non-precipitation conditions is to

 

decrease the freeze point

Maximum downdrafts in a microburst encounter may be as strong as

 

6,000 ft/min

What is a likely location of clear air turbulences?

 

In an upper trough on the polar side of a jetstream

Where do squall lines most often develop?

 

Ahead of a cold front

What weather condition occurs at the altitude where the dewpoint lapse rate and the dry adiabatic lapse rate converge?

 

Cloud bases form

If a sample of air is forced upward and it is colder than the surrounding air, it

 

sinks until it reaches denser air

METAR KSPS 131757Z 09014KT 6SM -RA SCT025 OVC090 24/22 A3005.
SPECI KSPS 131820Z 01025KT 3SM +RA FC OVC015 22/21 A3000.

Which change took place at Wichita Falls (KSPS) between 1757 and 1820 UTC?

 

A funnel cloud was observed

When flying in the rain and an air temperature of 1°C, a pilot should

 

be aware of the possibility of airframe icing

What is an important characteristic of wind shear? 

 

It may be associated with either a wind shift or a windspeed gradient at any level in the atmosphere

Where are jetstreams normally located?

 

In a break in the tropopause where intensified temperature gradients are located

Freezing rain encountered during climb is normally evidence that

 

a layer of warmer air exists above

What temperature condition is indicated if precipitation in the form of wet snow occurs during flight?

 

The temperature is above freezing at flight altitude

What is the minimum glycol content of Type 2 deicing/anti-icing fluid?

 

50 percent

What us a feature of a stationary front?

 

Surface winds tend to flow parallel to the frontal zone

How are haze layers cleared or dispersed?

 

By wind or the movement of air

What is the result when water vapour changes to the liquid state while being lifted in a thunderstorm?

 

Latent heat is released to the atmosphere

What is a feature of supercooled water?

 

The unstable water drop freezes upon striking an exposed object

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

Which of the following weather conditions are conducive to inflight icing?

 

Visible rain with temperatures below 0°C

What is the expected duration of an individual microburst?

 

Seldom longer than 15 minutes from the time the burst strikes the ground until dissipation

Cumulus clouds often indicate

 

possible turbulence

Clear air turbulence associated with a jet stream is

 

most commonly found in the vicinity of the tropopause

Why are downdrafts in a mature thunderstorm hazardous?

 

Downdrafts are kept cool by cold rain which tends to accelerate the downward velocity

A calm wind that is forecast, in the International Terminal Aerodrome Forecast (TAF) is encoded as

 

00000KT

What is the general direction of movement of a hurricane located in the Caribbean or Gulf of Mexico region?

 

Northwesterly curving to northeasterly

Where can the maximum hazard zone caused by wind shear associated with a thunderstorm be found?

 

On all sides and directly under the thunderstorm cell

Which type weather conditions are covered in the Convective SIGMET?

 

Embedded thunderstorms, lines of thunderstorms, and thunderstorms with 3/4-inch hail or tornadoes

Clear ice generally forms in outside temperature ranges of

 

0 to -10°C

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

 

4,000 ft thick

Temperature and radiation variations over land with a clear sky typically lead to 

 

incoming terrestrial radiation peaking at noon

If the winds aloft are blowing parallel to the front,

 

the front moves slowly if at all

Steep frontal surfaces are usually associated with

 

fast moving cold front

If icing is suspected on an airplane equipped with deicing equipment, the pilot should

 

operate the pneumatic deicing system several times to clear the ice

At lower levels of the atmosphere, friction causes the wind to flow across isobars into a low because the friction

 

decreases wind speed and Coriolis force.

What type turbulence should be reported when it causes changes in altitude and/or attitude more than two-thirds of the time, with the aircraft remaining in positive control at all times?

 

Continuous moderate turbulence

What condition produces the most frequent type of ground- or surface- based temperature inversion?

 

Terrestrial radiation on a clear, relatively calm night

Which weather condition is defined as an anti-cyclone? 

 

High pressure area

What hazard should you expect for a morning departure from KPDX, based on this METAR?
KPDX 271154Z 00000KT 9SM CLR -10/-10 A2979.

 

Frost on the aircraft

When does minimum temperature normally occur during a 24 hour period?

 

After sunrise

Constant Pressure Analysis Charts contain contours, isotherms and some contain isotachs. The contours depict

 

ridges, lows, troughs and highs aloft

Which conditions result in the formation of frost?

 

Temperature of the collecting surface is below the dewpoint and the dewpoint is also below freezing

Maximum turbulence potential charts (GTG-2) are issued

Hourly

Freezing Point Depressant (FPD) fluids are highly soluble in water; however,

 

ice is slow to absorb it, and to melt when in contact with it

What information from the control tower is indicated by the following transmission?

"SOUTH BOUNDARY WIND ONE SIX ZERO AT TWO FIVE, WEST BOUNDARY WIND TWO FOUR ZERO AT THREE FIVE."

 

There is a possibility of wind shear over or near the airport

Which condition is present when a local parcel of air is stable?

 

The parcel of air resists convection

What weather feature occurs at altitude levels near the tropopause?

 

Maximum winds and narrow wind shear zones

Which action is recommended regarding an altitude change to get out of jetstream turbulence?

 

Descend if ambient temperature is falling

winds Vertical wind shear can be determined by comparing winds on vertically adjacent constant pressure charts. The vertical wind shear is critical for probability of turbulence is 

 

6 knots or more per 1,000 feet

Convective clouds which penetrate a stratus layer can produce which threat to instrument flight?

 

Embedded thunderstorms

Which atmospheric factor causes rapid movement of surface fronts?

 

Upper winds blowing across the front

Which event usually occurs after an aircraft passes through a front into the colder air?

 

Atmospheric pressure increases

Maximum downdrafts in a microburst encounter may be as strong as

 

6,000 ft/min

A flight is schduled at daybreak. The current weather is rainy but is expected to clear, with temperature/dew point spread forecast to be 10 C/10 C and winds 330 at 5 kts. What weather conditions should you expect?

 

These conditions could produce radiation fog

Freezing Point Depressant (FPD) fluids used for deicing

 

are intended to provide ice protection on the ground only

Large areas of land

 

tend to increase temperature variations

Clouds with extensive vertical development over mountainous terrain are a sign of 

 

an unstable air mass

The symbol ($) at the end of the following METAR
indicates that
METAR KFSM 131756Z AUTO 00000KT M1/4SM R25/0600V1000FT -RA FG VV004 06/05 A2989 RMK AO2 $

 

maintenance is needed on the system

Which condition produces weather on the lee side of a large lake? 

 

Warm air flowing over a colder lake may produce fog

A strong wind shear can be expected

 

on the low pressure side of a 100-knot jetstream core

What action is required prior to takeoff if snow is adhering to the wings of an air carrier aeroplane?

 

Assure that the snow is removed from the aeroplane

Forecast winds and temperatures aloft for an international flight may be obtained by consulting

 

Wind and Temperature Aloft Charts prepared by the U.S. National Centers of Environmental Prediction (NCEP)

What is a characteristic of the troposphere?

 

There is an overall decrease of temperature with an increase of altitude

Embedded thunderstorms, which can be hazardous during instrument flight, are most likely to occur

 

in a warm front occlusion

What is the lowest cloud in the stationary group associated with a mountain wave?

 

Rotor cloud