Study Unit 8: Aviation Weather
You are avoiding a thunderstorm that is in your flightpath. You are over 20 miles from the cell however, you are under the anvil of the cell. Is this a hazard?A.Yes, hail can be discharged from the anvil. B.No, you are at a safe distance from the cell. C.Yes, this is still in the area of dissipation.
Answer (A) is correct. (AC 00-24C, AIM Para 7-1-28) ( ? )Pilots should anticipate possible hail with any thunderstorm, especially beneath the anvil of a large cumulonimbus.
The average height of the troposphere in the middle latitudes is A.37,000 feet. B.25,000 feet. C.20,000 feet.
Answer (A) is correct. (AC 00-6B Chap 1) ( ? )In the mid-latitudes, the average height of the troposphere is about 37,000 ft. It is 25,000 to 30,000 ft. at the poles and 55,000 to 65,000 ft. at the equator. It is generally higher in summer than in winter.
What temperature condition is indicated if wet snow is encountered at your flight altitude? A.The temperature is above freezing at your altitude. B.You are flying from a warm air mass into a cold air mass. C.The temperature is below freezing at your altitude.
Answer (A) is correct. (AC 00-6B Chap 14) ( ? )If snow is wet at your altitude, you are in above-freezing temperatures because the snow has started to melt.
A common type of ground or surface based temperature inversion is that which is produced by A.ground radiation on clear, cool nights when the wind is light. B.warm air being lifted rapidly aloft in the vicinity of mountainous terrain. C.the movement of colder air over warm air, or the movement of warm air under cold air.
Answer (A) is correct. (AC 00-6B Chap 17) ( ? )A temperature inversion means the temperature becomes warmer rather than cooler with increases in altitude. A ground- or surface-based temperature inversion is produced when the air near the surface is cooled faster than the overlying air as a result of radiation of heat on a clear, still night. The air very close to the surface is thus cooler than the air a few hundred feet above.
In which meteorological environment is aircraft structural icing most likely to have the highest rate of accumulation? A.Freezing rain. B.Cumulonimbus clouds. C.High humidity and freezing temperature.
Answer (A) is correct. (AC 00-6B Chap 18) ( ? )The condition most favorable for very hazardous icing is the presence of many large, supercooled water drops (i.e., freezing rain). The heaviest icing will usually be found at altitudes at or slightly above the freezing level where the temperature is never more than a few degrees below freezing.
The use of airborne weather-avoidance radar A.provides no assurance of avoiding instrument weather conditions. B.assures the avoidance of hail. C.allows you to fly safely between echoes.
Answer (A) is correct. (AC 00-6B Chap 20) ( ? )Weather-avoidance radar provides information on precipitation based on echo returns. Avoiding the heaviest areas of precipitation will often (not always) keep you out of the greatest turbulence. Radar does not show water vapor. Thus, clouds and fog, i.e., instrument weather conditions, are not indicated
The amount of water vapor which air can hold largely depends on A.air temperature. B.relative humidity. C.stability of air.
Answer (A) is correct. (AC 00-6B Chap 3) ( ? )Air temperature largely determines how much water vapor can be held by the air. Warm air, which is less dense, can hold more water vapor than cold air.
Tailplane icing can be detected by a(n) A.sudden uncommanded nose-down pitch. B.gradual uncommanded nose-up pitch. C.increase in elevator effectiveness.
Answer (A) is correct. (AC 91-74B) ( ? )A sudden uncommanded nose-down pitch is a symptom of tailplane icing that has caused a tailplane stall. The correct pilot reaction, unlike in a main wing stall, is to apply full aft-control pressure along with a reduction of the wing flaps to the last safe position.
Tailplane icing can be detected by A.elevator control pulsing, oscillations, or vibrations. B.an increase in elevator effectiveness. C.a gradual uncommanded reduction in engine power.
Answer (A) is correct. (AC 91-74B) ( ? )Elevator control pulsing, oscillations, or vibrations as well as any other unusual or abnormal pitch anomalies (possibly resulting in pilot induced oscillations) are indicative of tailplane ice accumulation. If installed, anti-ice equipment should be activated. If no anti-ice system is installed or if the accumulation is not sufficiently combated by the anti-ice system, the pilot should exit icing conditions immediately.
Roll upsets caused by ice accumulation forward of the ailerons can be remedied by A.reducing the angle of attack by increasing airspeed or extending wing flaps to the first setting and rolling wings level. B.retracting the flaps to decrease the angle of attack at a given airspeed and maintaining a level pitch attitude. C.decreasing engine power and maintaining a nose-low pitch attitude to dampen the rolling tendency of the wing tips.
Answer (A) is correct. (AC 91-74B) ( ? )Roll upsets are common during uneven ice accumulation on the wings. Because this ice accumulation builds forward of the ailerons and behind the deicing boots, it is often very difficult to remove. Reducing the angle of attack and increasing airspeed will assist you in maintaining positive control of the airplane
Where will the pilot first notice an accumulation of ice? A.On the air temperature probe. B.On the leading edge of the wing. C.On the propeller.
Answer (A) is correct. (AC 91-74B) ( ? )Small, narrow objects tend to pick up ice that is visually detectable. Strategically located protuberances may also serve as ice indicators. The air temperature probe is an excellent example of this.
Maximum downdrafts in a microburst encounter may be as strong as A.6,000 feet per minute. B.7,000 feet per minute. C.8,000 feet per minute
Answer (A) is correct. (AIM Para 7-1-26) ( ? )Downdrafts in a microburst can be as strong as 6,000 feet per minute. Horizontal winds near the surface can be as strong as 45 knots, resulting in a 90-knot wind shear. The strong horizontal winds occur within a few hundred feet of the ground.
What type of clouds will be formed if very stable moist air is forced up slope? A.Stratified clouds with little vertical development. B.Vertical clouds with increasing height. C.First stratified clouds and then vertical clouds.
Answer (A) is correct. (FAA-H-8083-25B Chap 12) ( ? )Even when being forced up slope, stable air forms stratus-type clouds. This is because the air resists any further upward movement.
Which conditions result in the formation of frost? A.Temperature of the collecting surface is below the dew point of surrounding air and the dew point is colder than freezing. B.The temperature of the collecting surface is at or below freezing and small droplets of moisture are falling. C.When dew forms and the temperature is below freezing.
Answer (A) is correct. (FAA-H-8083-25B Chap 12) ( ? )If the air temperature drops below the dew point, the air becomes more dense and can no longer hold the water vapor. The water vapor will condense to form visible moisture. Frost will form only if the temperature of the collecting surfaces is below the dew point of the surrounding air AND the dew point is below freezing.
What is an operational consideration if you fly into rain which freezes on impact?A.Temperatures are above freezing at some higher altitude. B.You have flown through a cold front. C.You have flown into an area of thunderstorms.
Answer (A) is correct. (FAA-H-8083-25B Chap 12) ( ? )Rain that freezes on impact is called freezing rain. If rain falls through freezing air, it will usually form supercooled water droplets, i.e., freezing rain. It indicates that temperatures somewhere above the airplane are above freezing.
A high cloud is composed mostly of A.ice crystals. B.ozone. C.condensation nuclei.
Answer (A) is correct. (FAA-H-8083-25B Chap 12) ( ? )The high cloud family is cirriform. It includes cirrus, cirrocumulus, and cirrostratus clouds. They are composed almost entirely of ice crystals. Their bases range from 16,500 ft. to 45,000 ft.
What types of fog depend upon a wind in order to exist? A.Steam fog and down slope fog. B.Advection fog and up slope fog. C.Precipitation-induced fog and ground fog.
Answer (B) is correct. (AC 00-6B Chap 16) ( ? )Up slope fog forms as a result of moist, stable air being cooled as it moves up a sloping terrain. Advection fog forms when moist air is blown over a cold surface, decreasing the moist air's temperature to its dew point. Thus, both up slope fog and advection fog depend on air moving from one area to another; i.e., they depend on wind.
Where do squall lines most often develop? A.In an occluded front. B.Ahead of a cold front. C.In a cold air mass.
Answer (B) is correct. (AC 00-6B Chap 19) ( ? )A squall line is a nonfrontal band of active thunderstorms that sometimes develops ahead of a cold front.
Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?A.Growth rate of cloud is maximum. B.The start of rain at the surface. C.Strong turbulence in the cloud.
Answer (B) is correct. (AC 00-6B Chap 19) ( ? )The mature stage of a thunderstorm is indicated when rain begins falling at the surface. This means that downdrafts have developed sufficiently to carry water all the way through the thunderstorm.
Unsaturated air flowing up slope will cool at the rate of approximately (dry adiabatic lapse rate) A.2°C per 1,000 feet. B.3°C per 1,000 feet. C.2.5°C per 1,000 feet.
Answer (B) is correct. (AC 00-6B Chap 6) ( ? )The dry adiabatic lapse rate signifies a prescribed rate of expansional cooling or compressional heating. The dry adiabatic rate is 3°C for each 1,000 feet. Note that this rate differs from the average normal lapse rate of 2°C for each 1,000 feet of altitude. The average lapse rate does NOT occur in dry air, but rather in air with "average" humidity.
Which force, in the Northern Hemisphere, acts at a right angle to the wind and deflects it to the right until parallel to the isobars?A.Pressure gradient. B.Coriolis. C.Centrifugal.
Answer (B) is correct. (AC 00-6B Chap 7) ( ? )Coriolis force is a result of the Earth's rotation. As the wind moves perpendicular to the isobars (from high to low pressure), it is apparently deflected to the right in the Northern Hemisphere, until it is moving parallel to the isobars. This effect is most pronounced above 2,000 ft. AGL.
When compared to winds at the surface, winds at 2,000 feet are A.higher and go at right angles to the isobars due to friction. B.higher due to absence of friction. C.higher because they move from an area of higher pressure to lower pressure.
Answer (B) is correct. (AC 00-6B Chap 7) ( ? )Friction between the wind and the terrain surface slows the wind. The rougher the terrain, the greater the frictional effect.
What relationship exists between the winds at 2,000 feet above the surface and the surface winds?A.The winds at 2,000 feet and the surface winds flow in the same direction, but the surface winds are weaker due to friction. B.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. C.The surface winds tend to veer to the right of the winds at 2,000 feet and are usually weaker.
Answer (B) is correct. (AC 00-6B Chap 7) ( ? )Generally, winds near the surface are weaker than those aloft due to the friction between the Earth's surface and the wind. Also, because they are slower, winds near the surface are less affected by the Coriolis force. The pressure gradient forces are thus stronger near the surface, and the winds cross the isobars at an angle instead of flowing parallel to them.
Test data indicates that ice, snow, or frost having a thickness and roughness similar to medium or coarse sandpaper on the leading edge and upper surface of an airfoil can A.increase drag and reduce lift by as much as 40 percent. B.reduce lift by as much as 30 percent and increase drag by 40 percent. C.reduce lift by as much as 40 percent and increase drag by 30 percent.
Answer (B) is correct. (AC 120-58, page 4) ( ? )Lift has been shown to be reduced by as much as 30%, while drag may be increased by up to 40% when ice, snow, or thick frost is present on the leading edge and upper surface of the wing.
When using deicing boots, the pilot should A.wait for a 1/4-inch to 1/2-inch layer of ice to form before cycling the boots to avoid ice bridging. B.activate the deicing system at the first indication of icing and do so in accordance with the manufacturer's guidance. C.deactivate the deicing system immediately after exiting the known icing conditions.
Answer (B) is correct. (AC 91-74B) ( ? )Due to the immediate and serious effects of ice accumulation, the FAA and manufacturer's guidance recommend that operators activate deicing boots at the first indication of ice accumulation.
Where is airplane icing most difficult to identify? A.On the trailing edge of the wing. B.On the flat upper wing surface. C.On the wing's leading edge.
Answer (B) is correct. (AC 91-74B) ( ? )Ice accumulation on the wing's upper surface may be very difficult to detect from the flight deck, cabin, or front or back of the wing. Additionally, frost, snow, and rime ice may be very difficult to detect on a white upper wing surface.
Should you experience uncommanded roll due to icing forward of the ailerons, the most appropriate response is to A.begin a climb. B.reduce the angle of attack by reducing the aircraft pitch, and if in a turn, roll wings level. C.retract the flaps in increments and employ available ice removal equipment.
Answer (B) is correct. (AC 91-74B) ( ? )If you encounter uncommanded roll due to ice accumulations forward of the ailerons, pilots can remedy roll up sets using the following guidelines: 1. Reduce the angle of attack by reducing the aircraft pitch. If in a turn, the pilot should roll the wings level. 2. Set the appropriate power and monitor the airspeed and angle of attack. 3. If flaps are extended, do not retract them unless it can be determined that the upper surface of the airfoil is clear of ice. Retracting the flaps will increase the angle of attack at a given airspeed. 4. Verify wing protection is functioning normally and systematically through visual observation of each wing.
Which is true concerning aircraft icing? A.Small, almost imperceptible amounts of ice on the wing's upper surface cause the same aerodynamic penalties as much larger and more visible accumulations. B.Small amounts of ice on the wing's surface usually result in correspondingly less performance degradation than larger amounts. C.Ice accumulation on the wing's leading edge that conforms to the wing contour generally results in little performance degradation.
Answer (B) is correct. (AC 91-74B) ( ? )Light icing is generally less of a problem aerodynamically than heavy icing. Light icing is slightly more difficult to remove with most deicing systems, but it is considered less of an immediate threat than heavy icing.
Which of the following would be an accurate description of supercooled large droplets (SLD)? A.Subfreezing water drops greater than 50 microns at the surface. B.Subfreezing water drops greater than 50 micrometers located in or below clouds. C.Subfreezing water drops greater than 40 microns located in or below clouds.
Answer (B) is correct. (AC 91-74B) ( ? )SLDs are drops of subfreezing water that are 50 micrometers or greater in size. When present, these droplets will be found in or below clouds.
When is an airplane most likely to be struck by lightning?A.Independent of OAT. B.OAT between -5°C and +5°C. C.OAT greater than 0°C.
Answer (B) is correct. (AIM Para 7-1-27) ( ? )The greatest probability of a lightning strike occurs when flying with an outside air temperature (OAT) of between -5°C and +5°C. Lightning strikes with aircraft are extremely rare but can occur whenever you operate near a thunderstorm, even if you are in the clear.
Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high? A.Light wind shear and poor visibility due to haze and light rain. B.Smooth air and poor visibility due to fog, haze, or low clouds. C.Turbulent air and poor visibility due to fog, low stratus-type clouds, and showery precipitation.
Answer (B) is correct. (FAA-H-8083-25B Chap 12) ( ? )A temperature inversion is an increase in temperature as altitude increases; normally temperature decreases with increases in altitude. In an inversion, warm air rises to its own temperature and forms a stable layer of air. A low-level inversion results in poor visibility by trapping fog, smoke, dust, etc., in low levels of the atmosphere
The stability of an air mass can usually be determined by A.measuring the dry adiabatic lapse rate. B.cloud types and the type of precipitation. C.the height of the tropopause.
Answer (B) is correct. (FAA-H-8083-25B Chap 12) ( ? )Atmospheric stability influences weather by affecting the vertical motion of air. Stable air suppresses vertical motion, but unstable air enhances it. Clouds formed in stable air will be shallow and layered, e.g., stratus clouds. Clouds formed in unstable air will have more height and be of the cumulus or cumulonimbus type. Precipitation from stratus clouds tends to be over large areas and lasts for long periods. Precipitation from cumulus clouds tends to be more intense and lasts for short periods.
Which clouds have the greatest turbulence? A.Towering cumulus. B.Cumulonimbus. C.Altocumulus castellanus.
Answer (B) is correct. (FAA-H-8083-25B Chap 12) ( ? )Cumulonimbus clouds are thunderstorms and the ultimate manifestation of instability. They are huge vertically developed clouds with dense, billowy tops often crowned with thick veils of dense cirrus, called the "anvil." Nearly the entire spectrum of flying hazards is contained in these clouds, including violent turbulence.
What are the four families of clouds? A.Clouds formed by updrafts, fronts, cooling layers of air, and precipitation into warm air. B.High, middle, low, and those with extensive vertical development. C.Stratus, cumulus, nimbus, and cirrus.
Answer (B) is correct. (FAA-H-8083-25B Chap 12) ( ? )For identification purposes, clouds are divided into four "families" based on their height range. The families are high clouds, middle clouds, low clouds, and clouds with extensive vertical development.
A temperature inversion will normally form only A.when a stratiform layer merges with a cumuliform mass. B.in stable air. C.in unstable air.
Answer (B) is correct. (FAA-H-8083-25B Chap 12) ( ? )In a temperature inversion, warm air overlies colder air; i.e., the lapse rate is inverted. By definition, this is a stable condition since there is no lifting action.
What are the characteristics of an unstable atmosphere?A.Descending air in the northern hemisphere. B.A warm, humid air mass. C.A cool, dry air mass.
Answer (B) is correct. (FAA-H-8083-25B Chap 12) ( ? )The stability of the atmosphere depends on its ability to resist vertical motion. As air temperature and air moisture increase, the density of the air decreases, causing it to rise. This creates an unstable atmosphere in which small vertical air movements tend to become larger, resulting in turbulent airflow and convective activity.
If squalls are reported at your destination, what wind conditions should you anticipate? A.Peak gusts of at least 35 knots for a sustained period of 1 minute or longer. B.Sudden increases in wind speed of at least 16 knots rising to 22 knots or more, lasting for at least 1 minute. C.Rapid variation in wind direction of at least 20° and changes in speed of at least 10 knots between peaks and lulls.
Answer (B) is correct. (NOAA Glossary)A squall is a sudden increase in wind speed by at least 16 knots, rising to 22 knots or more, and lasting for at least 1 minute. In contrast, a wind gust is a brief increase in wind with a variation between peaks and lulls of at least 10 knots. Note that these definitions involve variations in wind speed, not wind direction.
Hazardous wind shear is commonly encountered near the ground A.during periods when the wind velocity is stronger than 35 knots and near mountain valleys. B.during periods when the wind velocity is stronger than 35 knots. C.during periods of strong temperature inversion and near thunderstorms.
Answer (C) is correct. (AC 00-54) ( ? )Thunderstorms produce hazardous wind shear near the ground. Wind shear during temperature inversions is also hazardous when at low levels as it affects aircraft approaching and departing airports.
A characteristic of the stratosphere is A.an overall decrease of temperature with an increase in altitude. B.a relatively even base altitude of approximately 35,000 feet. C.relatively small changes in temperature with an increase in altitude.
Answer (C) is correct. (AC 00-6B Chap 1) ( ? )The stratosphere is the atmospheric layer above the tropopause. It is the band of altitude from about 7 to 22 mi. It is characterized by a slight average increase in temperature from base to top and thus is very stable. It also has a low moisture content and an absence of clouds.
Frontal waves normally form onA.slow moving warm fronts and strong occluded fronts.B.rapidly moving cold fronts or warm fronts.C.slow moving cold fronts or stationary fronts.
Answer (C) is correct. (AC 00-6B Chap 10) ( ? )Frontal waves and cyclones (areas of low pressure) usually form in slow-moving cold fronts or in stationary fronts.
The suffix "nimbus", used in naming clouds, means a A.dark massive, towering cloud. B.cloud with extensive vertical development. C.rain cloud.
Answer (C) is correct. (AC 00-6B Chap 13) ( ? )The prefix "nimbo" or the suffix "nimbus" means raincloud. For example, stratified clouds from which rain is falling are called nimbostratus clouds. A heavy, swelling, cumulus-type cloud which produces precipitation is called a cumulonimbus cloud.
What situation is most conducive to the formation of radiation fog? A.The movement of cold air over much warmer water. B.Moist, tropical air moving over cold, offshore water. C.Warm, moist air over low, flatland areas on clear, calm nights.
Answer (C) is correct. (AC 00-6B Chap 16) ( ? )Conditions favorable for radiation fog are a clear sky, little or no wind, and a small temperature-dew point spread. The fog forms as terrestrial radiation cools the ground. The air close to the surface cools more quickly than the slightly higher air. The air near the ground is cooled to dew point, and fog forms.
Which conditions are favorable for the formation of radiation fog?A.Moist air moving over colder ground or water. B.Cloudy sky and a light wind moving saturated warm air over a cool surface. C.Clear sky, little or no wind, small temperature/dew point spread, and over a land surface.
Answer (C) is correct. (AC 00-6B Chap 16) ( ? )Conditions favorable for radiation fog are a clear sky, little or no wind, and a small temperature-dew point spread. The fog forms as terrestrial radiation cools the ground. The air near the ground is cooled to dew point, and fog forms.
Clouds, fog, or dew will always form when A.the temperature and dew point are equal. B.water vapor is present. C.water vapor condenses.
Answer (C) is correct. (AC 00-6B Chap 3) ( ? )As water vapor condenses, it becomes visible as clouds, fog, or dew.
The strength and location of the jet stream is normally A.stronger and farther north in the summer. B.stronger and farther north in the winter. C.weaker and farther north in the summer.
Answer (C) is correct. (AC 00-6B Chap 8) ( ? )In the mid-latitudes, the wind speed in the jet stream averages considerably less in the summer than in the winter. Also, the jet stream shifts farther north in summer than in winter.
Which feature is associated with the tropopause? A.Absence of wind and turbulent conditions. B.Absolute upper limit of cloud formation. C.Abrupt change in temperature lapse rate.
Answer (C) is correct. (AC 00-6B Chap 8) ( ? )The tropopause is the transition layer of atmosphere between the troposphere (surface to about 7 to 22 mi.) and the stratosphere. A characteristic of the tropopause is that there is an abrupt change in the temperature lapse rate, i.e., the rate at which temperature decreases with height.
Standing lenticular clouds, in mountainous areas, indicate A.unstable air. B.an inversion. C.turbulence.
Answer (C) is correct. (AC 00-6B Chaps 13, 17) ( ? )The "waves" generated as wind flows across a mountain barrier may form standing lenticular clouds at the crest of each wave. Their presence indicates very strong turbulence, and they should be avoided.
Temperature and radiation variations over land with a clear sky typically lead to A.temperature reaching a maximum closer to noon than to sunset. B.outgoing terrestrial radiation peaking at noon. C.minimum temperature occurring after sunrise.
Answer (C) is correct. (AC 00-6B) ( ? )At night, heating is absent, but terrestrial radiation continues cooling the earth's surface. Cooling continues until shortly after sunrise, when incoming solar radiation once again exceeds outgoing terrestrial radiation. Minimum surface air temperature usually occurs shortly after sunrise.
Cumulus clouds often indicate A.a temperature inversion. B.a dry adiabatic lapse rate. C.possible turbulence.
Answer (C) is correct. (AC 00-6B) ( ? )Cumulus clouds are formed in a convective updraft, build upward, and are associated with turbulence.
In an aircraft equipped with a pneumatic deicing system, the appropriate technique for removing ice is to A.confirm that ice has accumulated prior to engaging the pneumatic boots. B.operate the pneumatic deicing system once. C.operate the pneumatic deicing system several times.
Answer (C) is correct. (AC 91-74B) ( ? )To clear accumulated ice as well as residual ice that may be left between cycles, you should operate a pneumatic deicing system several times.
Which is true about ice formation on a wing surface?A.Ice or frost formation on a wing's upper surface will have no effect on takeoff performance as long as formations are distributed sparsely. B.Small ice or frost formation on a wing's upper surface is not as serious as a large accumulation of ice on the wing's leading edge. C.Ice or frost formation on a wing surface can result in localized, asymmetrical stalls on the wing resulting in roll control problems during lift off.
Answer (C) is correct. (AC 91-74B, NTSB Safety Alert SA-06) ( ? )The NTSB has found that small patches of ice or frost can result in localized, asymmetrical stalls on the wing, which can result in roll control problems during lift off.
What is true regarding ice accumulations on a wing surface? A.A thin layer of ice on a wing's upper surface will result in little performance degradation if the ice is relatively smooth. B.Frost, snow, and rime ice is easily detectable on a white upper wing surface, while clear ice is difficult to detect. C.Small, visually imperceptible amounts of ice on a wing's surface during takeoff can result in significant performance degradation.
Answer (C) is correct. (AC 91-74B, NTSB Safety Alert SA-06) ( ? )Virtually imperceptible amounts of ice on a wing's upper surface can result in significant performance degradation.
A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or attitude should report it as A.light chop. B.moderate turbulence. C.light turbulence.
Answer (C) is correct. (AIM Para 7-1-23) ( ? )Light turbulence is defined as a disturbed air flow that momentarily causes slight erratic changes in altitude and/or attitude.
What is the expected duration of an individual microburst? A.Two minutes with maximum winds lasting approximately 1 minute. B.One microburst may continue for as long as 2 to 4 hours. C.Seldom longer than 15 minutes from the time the burst strikes the ground until dissipation.
Answer (C) is correct. (AIM Para 7-1-26) ( ? )An individual microburst will seldom last longer than 15 min. from the time it strikes ground until dissipation. The horizontal winds continue to increase during the first 5 min. with maximum-intensity winds lasting approximately 2 to 4 min.
An aircraft that encounters a headwind of 45 knots, within a microburst, may expect a total shear across the microburst of A.80 knots. B.40 knots. C.90 knots.
Answer (C) is correct. (AIM Para 7-1-26, AC 00-54) ( ? )If a headwind in a microburst is 45 knots, the wind will be going in the opposite direction on the other side of the microburst at presumably the same 45 knots, resulting in a wind shear between the headwind and tailwind of 90 knots.
Penetrating fog while flying an approach at night, you might experience the illusion of A.constant turning. B.flying at a lower altitude. C.pitching up.
Answer (C) is correct. (AIM Para 8-1-5) ( ? )Refractory effects can cause the perception of a nose high attitude.
The most frequent type of ground- or surface-based temperature inversion is that produced by A.the movement of colder air under warm air, or the movement of warm air over cold air. B.warm air being lifted rapidly aloft in the vicinity of mountainous terrain. C.radiation on a clear, relatively still night.
Answer (C) is correct. (FAA-H-8083-25B Chap 12) ( ? )An inversion often develops near the ground on clear, cool nights when the wind is light. The ground radiates heat and cools much faster than the overlying air. Air in contact with the ground becomes cold, while the temperature a few hundred feet above changes very little. Thus, temperature increases with height
Fair weather cumulus clouds often indicate A.smooth flying conditions. B.poor visibility. C.turbulence at and below the cloud level.
Answer (C) is correct. (FAA-H-8083-25B Chap 12) ( ? )Fair weather cumulus clouds form in convective currents and are characterized by relatively flat bases and dome-shaped tops. They indicate a shallow layer of instability, some turbulence, and no significant icing.
Which is a characteristic of low-level wind shear as it relates to frontal activity? A.Turbulence will always exist in wind-shear conditions. B.With a cold front, the most critical period is just before the front passes the airport. C.With a warm front, the most critical period is before the front passes the airport.
Answer (C) is correct. (FAA-H-8083-25B Chap 12) ( ? )Wind shear associated with a warm front occurs above an airport before the front passes the airport. A warm front is warmer air overtaking colder air.
Which procedure is recommended if a pilot should unintentionally penetrate embedded thunderstorm activity? A.Reduce airspeed to maneuvering speed and maintain a constant altitude. B.Reverse aircraft heading or proceed toward an area of known VFR conditions. C.Set power for recommended turbulence penetration airspeed and attempt to maintain a level flight attitude.
Answer (C) is correct. (FAA-H-8083-25B Chap 5) ( ? )If a thunderstorm is penetrated, you should always attempt to maintain a constant attitude at or below the maneuvering or turbulence penetration speed recommended for the airplane. Note that the airspeed cannot always be kept constant, but the power can be set so that you will be operating generally at or below the maneuvering speed.
A generally recommended practice for autopilot usage during cruise flight in icing conditions is A.keeping the autopilot engaged while monitoring the system. B.periodically disengaging and immediately reengaging the altitude hold function. C.periodically disengaging the autopilot and hand flying the airplane
C periodically disengaging the autopilot and hand flying the airplane.
Where does wind shear occur?A.With either a wind shift or a wind speed gradient at any level in the atmosphere. B.Exclusively in thunderstorms. C.Wherever there is an abrupt decrease in pressure and/or temperature.
With either a wind shift or a wind speed gradient at any level in the atmosphere.Answer (A) is correct. (AC 00-54) ( ? )Wind shear can occur at any level where winds are blowing in different directions (wind shift) or at different speeds (a wind speed gradient).