Weather Flashcards
The average height of the troposphere in the middle latitudes is
37,000 feet
When is the wind group at one of the forecast altitudes omitted at a specific location or station in the winds and temperatures aloft forecast (FB)? When the wind
at the altitude is within 1,500 feet of the station elevation
Where does wind shear occur?
With either a wind shift or a wind speed gradient at any level in the atmosphere.
A station is forecasting wind and temperature aloft at FL 390 to be 300 degree at 200 knots; temperature -54 degree C. How would this data be encoded in the FB?
809954
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
In the northern hemisphere, surface wind spirals clockwise and outward from high pressure and counterclockwise and inward into low pressure. Where would wind not be consistent with this concept?
over mountainous areas
What is the expected duration of an individual microburst?
seldom longer than 15 minutes from the time the burst strikes the ground until dissipation
The amount of water vapor which air can hold largely depends on
air temperature
Which clouds have the greatest turbulence?
cumulonimbus
What is an important characteristic of wind shear?
It may be associated with either a wind shift or a wind speed gradient at any level in the atmosphere.
What is the maximum forecast period for AIRMETs?
six hours
Which surface of the airplane accumulates more ice first?
the tailplane
In which situation is advection fog most likely to form?
an air mass moving inland from the coast in winter
In severe icing conditions, accumulation of ice on the wing aft of the deicing boot but in front of the aileron may cause
roll upset
Thrust is managed to maintain IAS, and glideslope 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
Which weather product is a concise statement of the expected weather for an airport runway complex?
Terminal Aerodrome Forecast (TAF)
Why is frost considered hazardous to flight operation?
Frost causes early airflow separation resulting in a loss of lift
The use of airborne weather-avoidance radar
provides no assurance of avoiding instrument weather conditions
What is an operational consideration if you fly into rain which freezes on impact?
Temperatures are above freezing at some higher altitude
While flying a 3 degree glideslope, 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 glideslope
Graphical Forecasts for Aviation (GFA) are weather charts best used to
learn the forecast weather along your proposed route of flight as well as your destination if it has no terminal forecast
When climbing or descending through a temperature inversion or an area of possible wind shear, the pilot should be aware of
a rapid change of airspeed
What is the correct procedure to recover from roll upset?
lower the angle of attack and adjust the power for a controlled descent
What type clouds can be expected when an unstable air mass is forced to ascend a mountain slope?
Clouds with extensive vertical development
A ceiling is defined as the height of the
lowest layer of clouds or obscuring phenomena aloft that is reported as broken or overcast
In what localities is advection fog most likely to occur?
coastal areas
What type of clouds will be formed if very stable moist air is forced upslope?
stratified clouds with little vertical development
What wind direction and speed is represented by the entry 9900+00 for 9000 feet, on a winds and temperatures aloft forecast (FB)?
light and variable; less than 5 knots
A high cloud is composed mostly of
ice crystals
What are the requirements for the formation of a thunderstorm?
sufficient moisture, an unstable lapse rate, and a lifting action
A generally recommended practice for autopilot usage during cruise flight in icing conditions is
periodically disengaging the autopilot and hand flying the airplane
Which is a characteristic of stable air?
Stratiform clouds
When operating an airplane equipped with deicing boots, when is the appropriate time to turn them on?
As soon as ice starts to develop on the boot or per the manufacturer’s recommendations
What is the time frame for the validity of low-level significant weather prog charts?
12 to 24 hours in the future
What situation is most conducive to the formation or radiation fog?
Warm, moist air over low, flatland areas on clear, calm nights
Which meteorological condition is issued in the form of a SIGMET (WS)?
Widespread sand or dust storms affecting at least 3000 square miles or an area deemed to have a significant effect on the safety of aircraft.
Frontal waves normally form on
slow moving cold fronts or stationary fronts
Where can supercooled large drops (SLD) form?
In freezing precipitation below a cloud deck
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
To which meteorological condition does the term dew point refer?
the temperature to which air must be cooled to become saturated
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
What relationship exists between the winds at 2000 feet above the surface and the surface winds?
The winds at 2000 feet tend to parallel the isobars while the surface winds cross the isobars at an angle toward lower pressure and are weaker.
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, or
3. an anti-icing system on the aircraft
Which statement(s) is/are true?
only statements 2 and 3 are true
If you fly into severe turbulence, which flight condition should you attempt to maintain?
level flight attitude
What temperature condition is indicated if wet snow is encountered at your flight altitude?
the temperature is above freezing at your altitude
If squalls are reported at your destination, what wind conditions should you anticipate?
Sudden increases in wind speed or at least 16 knots, rising to 22 knots or more, lasting for at least 1 minute
When passing through an abrupt wind shear which involves a shift from a tailwind to a headwind, what power management would normally be required to maintain a constant indicated airspeed and ILS glideslope?
Lower than normal power initially, followed by a further decrease as the wind shear is encountered, then an increase
The presence of standing lenticualr altocumuls clouds is a good indication of
very strong turbulence
The general characteristics of unstable air are
good visibility, showey precipitation, and cumuliform type clouds
Which of the following combinations of 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
If you encounter in flight icing and ATC asks you to report your conditions, what are the official reportable icing values that you are expected to use?
Trace, light, moderate, severe
Fair weather cumulus clouds often indicate
turbulence at and below the cloud level
Standing lenticular clouds, in mountainous areas, indicate
turbulence
The most hazardous aspect of structural icing is
aerodynamic degradation including loss of lift
A characteristic of the stratosphere is
relatively small changes in temperature with an increase in altitude