156 terms

Instrument Written

In which meteorological environment is aircraft structural icing most likely to have the highest rate of accumulation?
Freezing Rain
The amount of water vapor which air can hold largely depends on?
Air Temperature
The most frequent type of ground- or surface-based temperature inversion is that produced by?
Radiation on a clear, relatively still night.
What is an indication that downdrafts have developed and the thunderstorm cell has entered the mature stage?
Precipitation begins to fall from the cloud base.
What causes surface winds to flow across the isobars at an angle rather than parallel to the isobars?
Surface friction.
What is an important characteristic of wind shear?
It is an atmospheric condition that may be associated with a low-level temperature inversion, a jet stream, or a frontal zone.
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.
What is a characteristic of stable air?
Stratiform Clouds.
The most hazardous aspect of structural icing is that?
It can result in aerodynamic degradation including loss of lift.
The first place ice is likely to form on an aircraft is the?
What feature is associated with a temperature inversion?
A stable layer of air.
Stability can be determined from which measurement of the atmosphere?
Ambient lapse rate.
What should pilots do if icing is detected while also experiencing a rolling condition
Set power and angle of attack for a controlled descent.
To which meteorological condition does the term 'Dew Point' refer?
The temperature to which air must be cooled to become saturated.
Hazardous wind shear is commonly encountered near the ground?
During periods of strong temperature inversion and near thunderstorms.
In which situation is advection fog most likely to form?
An air mass moving inland from the coast in winter.
Frontal waves normally form?
Slow moving cold fronts or stationary fronts.
How much colder than standard temperature is the forecast temperature at 9,000 feet, as indicated in the following excerpt from the Winds and Temperature Aloft Forecast?

FT 6000 9000
0737-04 1043-10
7 ℃.
What is an important characteristic of wind shear?
It may be associated with either a wind shift or wind speed gradient at any level in the atmosphere.
Which force, in the Northern Hemisphere, acts ata right angle to the wind and deflects it tot he right until parallel to the isobars?
What situation is most conducive to the formation of radiation fog?
Warm, moist air over low, flatland areas on clear, calm nights.
Where does wind shear occur?
With either a wind shift or wind speed gradient at any level in the atmosphere.
What enhances the growth rate of precipitation?
Upward Currents.
Which thunderstorms generally produce the most severe conditions, such as heavy hail and destructive winds?
Squall Line.
What types of fog depend upon a wind in order to exist?
Advection fog and up slope fog.
Steady precipitation, in contrast to showers, preceding a front is an indication of?
Stratiform clouds with little or no turbulence.
Which conditions are favorable for the formation of radiation fog?
Clear sky, little or now wind, small temperature/dew point spread, and over a land surface.
Maximum downdrafts in a microburst encounter may be as strong as?
6,000 feet per minute
Which are characteristics of an unstable cold air mass moving over a warm surface?
Cumuliform clouds, turbulence, and good visibility.
The presence of standing lenticular altocumulus clouds is a good indication of?
Very strong turbulence.
What relationship exists between the winds at 2,000 feet above the surface and the surface winds?
The winds at 2,000 feet tend to parallel the isobars while the surface winds cross the isobars at an angle toward lower pressure and are weaker.
The general characteristics of unstable air are?
good visibility, showery precipitation, and cumuliform-type clouds.
If the air temperature is +8℃ at an elevation of 1,350 feet and a standard (average) temperature lapse rate exists, what will be the approximate freezing level.
5,350 feet MSL.
What are the requirements for the formation of a thunderstorm?
Sufficient moisture, an unstable lapse rate, and a lifting action.
Which family of clouds is least likely to contribute to structural icing on an aircraft?
High Clouds.
Standing lenticular clouds, in mountainous areas, indicate.
What are the four families of clouds?
High, Middle, Low, and those with extensive vertical development.
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.
(Refer to Figure 13.) What effect will a microburst encounter have upon the aircraft in position 4?
Strong tailwind.
What type of clouds can be expected when an unstable air mass is forced to ascend a mountain slope?
Clouds with extensive vertical development.
Test data indicate that ice, snow, or frost having a thickness and roughness similar to medium or coarse sandpaper o the leading edge and upper surface of an airfoil can.
Reduce lift by as much as 30 percent and increase drag by 40 percent.
When a climb or descent through an inversion or wind-shear zone is being performed, the pilot should be alert for which of the following change in airplane performance?
A sudden change in airspeed.
Clouds, fog, or dew will always form when
Water vapor condenses.
The primary cause of all changes in the Earth's weather is?
Variation of solar energy received by the Earth's regions.
Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high.
Smooth air and poor visibility due to fog, haze, or low clouds.
What autopilot function should you turn off if icing is suspected?
Turn autopilot off.
If a pilot encounters freezing drizzle, he can assume that?
There is warmer air above.
What actions should the pilot take in the event of suspected tailplane icing during an approach
Use partial or no flaps and no autopilot.
In what localities is advection fog most likely to occur?
Coastal areas.
What determines the structure or type of clouds which form as a result of air being forced to ascend?
The stability of the air before lifting occurs.
Under which condition does advection fog usually form?
Moist air moving over colder ground or water.
Which weather condition can be expected when moist air flows from a relatively warm surface to colder surface.
Pilots should check for ice accumulation prior to flight by
Using a flashlight to reflect off white wing.
When passing through an abrupt wind shear which involves a shift from a tailwind to headwind, what power management would normally be required to maintain a constant indicated airspeed and ILS glide slope?
Lower than normal power initially, followed by further decrease as the wind shear is encountered, then an increase.
If you fly into severe turbulence, which flight condition should you attempt to maintain?
Level flight attitude.
A jet stream is defined as wind of?
50 knots or greater.
While flying a 3° glide slope, a constant tailwind shears to a calm wind. Which conditions should the pilot expect?
Airspeed and pitch attitude increase and there is a tendency to go above glide slope.
Why is frost considered hazardous to flight operation?
Frost causes early airflow separation resulting in a loss of lift.
(Refer to figure 13.) The aircraft in position 3 will experience which effect in a microburst encounter?
Strong downdraft.
(Refer to figure 13.) How will the aircraft in position 4 be affected by a microburst encounter?
Performance decreasing with a tailwind and downdraft.
What is an operational consideration if you fly into rain which freezes on impact?
Temperatures are above freezing at some higher altitude
(Refer to Figure 13.) If involved in a microburst encounter, in which aircraft positions will the most severe downdraft occur?
3 and 4
A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or attitude should report it as
Light turbulence.
Where do squall lines most often develop?
Ahead of a cold front.
If squalls are reported at your destination, what wind conditions should you anticipate?
Sudden increase in wind speed of at least 16 knots, rising to 22 knots or more, lasting for at least 1 minute.
If severe turbulence is encountered during your IFR flight, the airplane should be slowed to the design maneuvering speed because the?
Amount of excess load that can be imposed on the wing will be decreased.
During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?
If tailplane icing or a tailplane stall is detected, the pilot should?
Retract flaps and increase power.
The presence of ice pellets at the surface is evidence that
There is freezing rain at a higher altitude
Which weather phenomenon is always associated with the passage of a frontal system?
A wind change
Which is a characteristic of low-level wind shear as it relates to frontal activity?
With a warm front, the most critical period is before the front passes the airport.
A high cloud is compsed mostly of
Ice Crystals.
Which clouds have the greatest turbulence?
Which procedure is recommended if a pilot should unintentionally penetrate embedded thunderstorm activity?
Set power for recommended turbulence penetration airspeed and attempt to maintain a level flight attitude.
During an IFR cross-country flight you picked up rime icing which you estimate is 1/2" thick on the leading edge of the wings. You are now below the clouds at 2000 feet AGL and approaching your destination airport under VFR. Visibility under the clouds is more than 10 miles, winds at the destination airport are 8 knots right down the runway, and the surface temperature is 3 degrees Celsius. You decide to?
Use a faster than normal approach and landing speed.
Fair weather cumulus clouds often indicate
Turbulence at and below the cloud level.
When flying through supercooled water droplets, the first sign of structural ice accumulation would be
On probes and antennas.
The average height of the troposphere in the middle latitudes is
37,000 feet.
A common type of ground or surface based temperature inversion is that which is produced by
Ground radiation on clear, cool nights when the wind is light.
What temperature condition is indicated if wet snow is encountered at your flight altitude?
The temperature is above freezing at your altitude.
(Refer to Figure 13.) When penetrating a microburst, which aircraft will experience an increase in performance without a change in pitch or power?
What is the expected duration of an individual microburst?
Seldom longer than 15 minutes from the time the burst strikes the ground until dissipation.
What are the characteristics of stable air?
Poor visibility, steady precipitation, and stratus-type clouds.
A temperature inversion will normally form only?
In stable air
Preventing ice from causing a hazard for aircraft certificated for flight into known icing conditions is accomplished by
1. Spraying alcohol or glycol solution on the aircraft before takeoff.
2. A deicing system on the aircraft
3. An anti-icing system on the aircraft.
Which statement is true
Only statements 2 and 3 are true
An air mass is a body of air that
Covers an extensive area and has fairly uniform properties of temperature and moisture.
Where can wind shear associated with a thunderstorm be found? Choose the most complete answer.
On all sides of the thunderstorm cell and directly under the cell.
Tailplane icing can be detected by
A sudden change in elevator force or uncommanded nose-down pitch
The strength and location of the jet stream is normally
Weaker and farther north in the summer
Fog is usually prevalent in industrial areas because of
An abundance of condensation nuclei from combustion products.
Which weather phenomenon signals the beginning of the mature stage of a thunderstorm.
The start of rain at the surface.
Which precipitation type normally indicates freezing rain at higher altitudes?
Ice pellets
Winds at 5,000 feet AGL on a particular flight are southwesterly while most of the surface winds are southerly. This difference in direction is primarily due to
Friction between the wind and the surface.
An aircraft that encounters a headwind of 45 knots, within a microburst, may expect a total shear across the microburst of
90 knots
The suffix 'nimbus', used in naming clouds, means a
Rain Cloud
While flying a 3° glide slope , a headwind shears to a tailwind. Which conditions should the pilot expect on the glide slope?
Airspeed and pitch attitude decrease and there is a tendency to go below glide slope
Thrust is managed to maintain IAS, and glide slope is being flown. What characteristics should be observed when a headwind shears to be a constant tailwind?
PITCH ATTITUDE: Decreases; REQUIRED THRUST: Increased, then reduced; VERTICAL SPEED: Increases; IAS: Decreases, then increases to approach speed.
A characteristic of the stratosphere is
Relatively small changes in temperature with an increase in altitude
When flying through stratiform clouds, the best way to alleviate icing is by
Changing altitude to one with above-freezing temperatures or where temperatures are colder than -10℃
Unsaturated air flowing up slope will cool at the rate of approximately (dry adiabatic lapse rate)
3℃ per 1,000 feet.
Which conditions result in the formation of frost?
Temperature of the collecting surface is below the dewpoint of surrounding air and the dewpoint is colder than freezing.
Expect clear ice to form on the leading edge of airfoils when
Temperatures are close to freezing, there is a large volume of liquid water precipitation and the aircraft is at high airspeeds.
What type of clouds will be formed if very stable air is forced up slope?
Stratified clouds with little vertical development
Which weather phenomenon is always associated with a thunderstorm?
Which of the following combinations fo weather producing variables would likely result in cumuliform-type clouds, good visibility, rain showers, and possible clear-type icing in clouds?
Unstable, moist air, and orographic lifting
What are some characteristics of unstable air?
Turbulence and good surface visibility.
What is indicated by the term 'embedded thunderstorms'?
Thunderstorms are obscured by massive cloud layers and cannot be seen.
Which feature is associated with the tropopause?
Abrupt change in temperature lapse rate.
A station is forecasting wind and temperature aloft at FL 390 to be 300° at 200 knots; temperature -54°C. How would this data be encoded in the FD?
What is the maximum forecast period for AIRMETs?
Six hours
Which response most closely interprets the following PIREP?
UA/OV OKC 063064/TM 1522/FL080/TP C172/TA M04/WV 245050/TB LGT/RM IN CLR
64 nautical miles on the 63° radial from Oklahoma City VOR at 1522 UTC, flight level 8,000 ft. Type of aircraft is a Cessna 172.
When is the temperature at one of the forecast altitudes omitted at a specific location or station in the Winds and Temperatures Aloft Forecast (FD)?
For the 3,000-foot altitude (level) or when the level is within 2,500 feet of station elevation
(Refer to Figure 12, arrow B.) What is the approximate wind direction and velocity at BOI (see arrow B)?
250°/95 knots.
What is meant by the entry in the remarks section of METAR surface report for KBNA?
METAR KBNA 211250z 33018KT 290V260 1/2SM R31/2700FT +SN BLSNFG VV008 00/M03 A2991 RMK RAE42SNB42
Rain ended 42 past the hour, snow began 42 past the hour
A pilot planning to depart at 1100Z on an IFR flight is particularly concerned about the hazard of icing. What sources reflect the most accurate information on icing conditions (current and forecast) at the time of departure?
Pilot weather reports (PIREPs), AIRMETs, and SIGMETs.
(Refer to Figure 18, SFC-400 MB.) The 24-Hour Low Level Significant Weather Prog at 12Z indicates that southwestern West Virginia will likely experience
Ceilings less than 1,000 feet, visibility less than 3 miles.
(Refer to Figure 9.) The Severe Weather Outlook Chart, which is used primarily for advance planning, provides what information
A 24 hour severe weather outlook for possible thunderstorm activity.
(Refer to Figure 8.) What weather conditions are depicted in the area indicated by arrow C on the Radar Summary Chart?
Area movement toward the northeast, strong to very strong echoes, and echo tops 28,000 feet MSL.
The body of a Terminal Aerodrome Forecast (TAF) covers a geographical proximity within a
5 statute mile radius from the center of an airport runway complex
(Refer to Figure 8.) What weather conditions are depicted in the area indicated by arrow B on the Radar Summary Chart
Weak to moderate echoes, rain showers increasing in intensity.
(Refer to Figure 8.) What weather conditions are depicted in the area indicated by arrow E on the Radar Summary Chart?
Highest echo tops 30,000 feet MSL, weak to moderate echoes, thunderstorms and rain showers, and cell movement toward northwest at 15 knots.
(Refer to Figure 9.) The Severe Weather Outlook Chart depicts
areas forecast to have thunderstorms.
(Refer to figure 7.) What weather conditions are depicted within the area indicated by arrow F?
Occasionally embedded cumulonimbus, base below 24,000 feet with tops to 48,000 feet.
The Low-Level Significant Weather Prognostic Chart depicts weather conditions
That are forecast to exist at a valid time shown on the chart.
From which primary source should you obtain information regarding the weather expected to exist at your destination at your estimated time of arrival?
Terminal Aerodrome Forecast
What flight planning information can a pilot derive from constant pressure charts?
Winds and temperatures aloft
(Refer to figure 7.) What weather conditions are depicted within the area indicated by arrow D?
Forecast isolated embedded cumulonimbus clouds with tops at 43,000 feet MSL, and less than 1/8 coverage.
(Refer to Figure 20.) What is the height of the tropopause over Kentucky?
A "VRB" wind entry in a Terminal Aerodrome Forecast (TAF) will be indicated when the wind is
3 knots or less
(Refer to figure 4.) The Weather Depiction Chart indicates the heaviest precipitation is occurring in
North Central Minnesota
(Refer to figure 7.) What weather conditions are depicted within the area indicated by arrow B?
Moderate turbulence from below 24,000 feet MSL to 37,000 feet MSL.
(Refer to figure 7.) The area indicated by arrow H indicates
Moderate turbulence at and below 34,000 feet.
(Refer to figure 8.) What weather conditions are depicted in the area indicated by arrow D on the Radar Summary Chart?
Intense to extreme echoes within the smallest contour, echo tops 29,000 feet MSL, and cell movement toward the northeast at 50 knots.
(Refer to figure 8.) What weather conditions are depicted in the area indicated by arrow F on the Radar Summary Chart?
Line of echoes; thunderstorms; highest echo tops 45,000 feet MSL; no line movement indicated.
A ceiling is defined as the height of the
Lowest layer of clouds or obscuring phenomena aloft that is reported as broken or overcast
Interpret this PIREP.
At 6,000 feet; between layers; moderate turbulence; moderate rain.
The Surface Analysis Chart depicts
Actual frontal positions, pressure patterns, temperature, dew point, wind, weather, and obstructions to vision at the valid time of the chart.
A prognostic chart depicts the conditions
Forecast to exist at a specific time in the future.
(Refer to Figure 12.) What is the approximate wind direction and velocity at 34,000 feet (see arrow C)?
290°/50 knots.
When are severe weather watch bulletins (WW) issued?
Unscheduled and issued as required.
What does Convective Outlook (AC) describe for a following 24 hour period?
General thunderstorm activity.
Which meteorological condition is issued in the form of SIGMET (WS)
Widespread meteorological condition is issued in the form of SIGMET (WS)
On what frequency should you obtain En Route Flight Advisory Service below FL180
Pilots on IFR flights seeking ATC in-flight weather avoidance assistance should keep in mind that
ATC radar limitations and, frequency congestion may limit the controllers capability to provide this service.
(Refer to Figure 8.) What weather conditions are depicted in the area indicated by arrow G on the Radar Summary Chart?
Echo bases 10,000 feet MSL; cell movement toward northeast at 15 knots; weak to moderate echoes; rain
(Refer to Figure 7.) What information is indicated by arrow A?
The height of the tropopause in hundreds of feet above MSL.
(Refer to Figure 18, SFC-400MB.) The U.S. Low Level Significant Weather Surface Prog Chart at 00Z indicates that northwestern Colorado and eastern Utah can expect
Moderate or greater turbulence from the surface to FL 240
What is the wind shear forecast in the following TAF?

KCVG 231051Z 231212 12012KT 4SM -RA BR OVC008 WS005/27050KT TEMPO 1719 1/2SM -RA FG FM1930 09012KT 1SM -DZ BR VV003 BECMG 2021 5SM HZ=
500 feet AGL from 270° at 50 KT.
(Refer to Figure 4.) What is the meaning of a brack (]) plotted to the right of the station circle on a weather depiction chart?
The station is an automated observation location
The reporting station orginating this Aviation Routine Weather Report has a field elevation of 620 feet. If the reported sky cover is one continuous layer, what is its thickness? (tops of OVC are reported at 6500 feet) METAR KMDW 121856Z AUTO 32005KT 1 1/2SM +RABR OVC007 17/16 A2980
5,180 feet.
(Refer to Figure 20.) What is the maximum wind velocity forecast in the jet stream shown on the high level Significant Weather Prognostic Chart over Canada
AIRMETs are issued on a scheduled basis every
Six hours
(Refer to Figure 9.) Using the DAY 2 CONVECTIVE OUTLOOK, what type of thunderstorms, if any may be encountered on a flight from Montana to Central California
(Refer to Figure 4.) The Weather Depiction Chart in the area of northwestern Wyoming, indicates
500-foot ceilings and continuous rain, less than 3 miles visibility.
(Refer to Figure 18, SFC-PROG.) The chart symbols shown in the Gulf of Mexico at 12Z and extending into AL, GA, SC and northern FL indicate a
Tropical Storm
Which is true regarding the use of airborne weather-avoidance radar for the recognition of certain weather conditions?
The radarscope provides no assurance of avoiding instrument weather conditions.