Lesson 25
The sizes of downbursts vary from ___ mile or less to more than ___ miles, and damaging winds can last 5 to 30 minutes and could reach speeds up to ____ knots.
1/2, 10, 120 knots
A microburst is a downburst that covers an area up to ____ miles along with peak winds as high as ____ knots and lasts 2 to 5 minutes
2.5, 150 knots
How long does a typical thunderstorm last?
30 minutes
______ wind is responsible for most weather-related accidents.
Adverse
______ is snow lifted from the surface of the earth by the wind to a height of 6 feet or more above the ground and blow about in such quantities that the reported horizontal visibility is reduces to less that 7 statute miles
Blowing snow
A high altitude turbulence phenomenon occuring in cloud free regions, associated with wind shear around a jet stream is called
CAT (clear air turbulence)
When the term is used in aviation, refers to a wind that is not parallel to the runway or path of an aircraft.
Crosswind
______ is a visible aggregate of minute water droplets based at the Earth's surface and reducing horizontal visibility to less than 5/8 statute mile.
Fog
______ is the most common and persistent weather hazard encountered in aviation.
Fog
____ is a sudden, brief increase in the speed of the wind.
Gust
Continued visual flight into ____ weather is the single greatest cause of fatal accidents.
IFR
Turbulence intensity classification that occupants may feel a sight strain against seat belts or shoulder straps, unsecured objects may be displaced slightly, and food service may be conducted and little or no difficulty walking?
Light (LGT)
To warn terminal controllers and pilols of microbursts, wind shear and gust fronts, what three systems has the FAA installed?
Low Level Wind Shear Alert System (LLWAS) Terminal Doppler Weather Radar (TDWR) Airport Surveillance Radar (ASR) - Weather system processor (WSP)
__________ is any wind more than 90 degrees to the longitudinal axis of the runway.
Tailwind
Which icing intensity classification becomes perceptible, the rate of accumulation slightly greater than sublimation, and de-icing/anti-icing equipment is not utilized unless encountered for an extended period of time (over 1 hour)?
Trace (TRACE)
It may be impossible to recover from _______ encountered at low altitude.
a microburst
What may happen if a pilot does not correctly compensate for the crosswind?
aircraft may drift off the side of the runway side load on landing gear might occur
Irregular mothion of an aircraft inflight, characterized by rapid up and down motion, cuased by rapid variation of atmosphere wind velocities is called
aircraft turbulence
Aircraft icing potential is dependent upon what four factors?
aircraft type and design altitude airspeed meteorological factors
While an aircraft is on approach, a shear from tailwind to a headwind causes:
airspeed increases nose to pitch up aircraft to rise upward above glideslope land long and could run out of runway
While an aircraft is on approach, a shear from headwind to a tailwind causes:
airspeed to decrease nose to pitch down aircraft to drop below glideslope
Most aircraft accidents related to instrument weather involve pilots who
and not instrument rated
What type of clouds indicate convective turbulence?
billowy cumuliform
Once the gust ends, what may this cause the aircraft to do when taking off?
bounce on the runway
When an airplane is taking off into a headwind, gusts may cause it to _______
bounce on the runway
What are the 4 types of clouds associated with a mountain wave?
cap cloud cirrocumulus standing lenticular (CCSL) Altocumulus standing lenticular (ACSL) Rotor cloud
______ is the lowest layer aloft reported as broken or overcast
ceiling
How would an aircraft avoid CAT?
change altitude
Two air traffic management decisions triggered by adverse winds are
change of runway configuration reduced arrival rates
_____ is a category of turbulence which causes rapud and somewhat rhythmic bumpiness without appreciable changes in altitude or attitude.
chop
What type of icing can greatly disruot airflow, pilot may not see, can be difficult to remove, and can spread beyond the reach or de-icing/anti-icing equipment?
clear
A glossy, clear, or translucent ice formed by relatively slow freezing of large supercooled water droplets is wht type of icing?
clear ice
When air is too dry for cumuliform clouds to form, ______ currents caused by uneven surface heating can still be active and cause turbulence.
convective
Three causes of turbulence are:
convective currents obstructions to wind flow wind shear
Turbulent vertical motion that result from convective currents (heat) and subsequent rising and sinking air
convective turbulence
Adverse wind phenomena include(5):
crosswinds gusts tailwind variable wind sudden wind shift
What type of cloud is associated with thunderstorms?
cumulonimbus
What type of request should a controller expect from a pilot in concerns to a thunderstorm?
deviation/route around
The stage of a downburst lifecycle that downdraft moves away from point of impact?
dissipation
What stage during its lifecycle of a thunderstorm does precipitation taper off and end, and the cloud gradually vaporizes from belwo leaving only a remnant anvil cloud?
dissipation stage
What are three manuvers a pilot must do to escape icing?
exit area with visible moisture climb or descend to positive temperatures climb to altitudes where temperature are too cold to support supercooled droplets
During what type of turbulence is the aircraft violently tosses about and practically impossible to control?
extreme (EXTRM)
Turbulence intensity classification that the aircraft is violently tossed about and is practically impossible to control, and may cause structural damage?
extreme (EXTRM)
The stage of a downburst lifecycle that evaporation and precipitationdrag forms downdraft?
formation
What are the three stages of a downburst lifecycle?
formation impact dissipation
As the wind turns more perpendicular to the runway to become a crosswind what happens to aircraft performance?
gradually decreases
The stage of a downburst lifecycle that downdraft quickly accelerates and strikes ground?
impact
Which adverse effect of structural icing is least significant to an aircraft?
increased weight
A gust _____ airspeed, which _______ lift, and may cause an aircraft to briefly rise.
increases, increases
Is a ceiling or an indefinite ceiling more hazardous?
indefinite ceiling
_______ is the ceiling classification that is applied when the reported ceiling is a surface based obscuration such as fog, mist, haze, smoke, or dust.
indefinite ceiling
Which type of aircraft will perform beeter in adverse wind conditions, due to its higher takeoff and approach speeds?
larger airplanes
With _____ ice, the rate of accumulation may create a problem if flight is prolonged (over 1 hour). Occasional use of de-icing/anti-icing equipment removes/prevents accumulation.
light
Turbulence intensity classification that momentarily causes slight, erratic changes in altitude and/or attitude (pitch, roll, yaw)
light (LGT)
What type of turbulence momentarily causes slight erratic changes in altitude and/or attitude (pitch, roll, yaw)?
light (LGT)
Which icing intensity classification has a rate of accumulation that may create a problem if flight is prolonged in this environment (over 1 hour), occasional use of de-icing/anti-icing equipment removes/prevents accumulation, and it does not present a problem if de-icing/anti-icing is used.
light (LGT)
Thunderstorm can produce almost every aviation weather hazard in one viciouc bundle, including:
lightning hail downburst/microburst tornado rapid pressure changes
Having a tailwind will cause an aircraft to have a _______ takeoff roll, a ________ initial climb, and a _____ landing roll required.
longer, smaller, longer
A wind shear of 10 knots or more per 100 feet in a layer more than 200 feet thich which occurs within 2,000 feet of the surface is called
low level wind shear (LLWS)
What stage during its lifecycle of a thunderstorm does precipitation downdraft reaches the surface, the leading edge of downdraft air is called a "gust front", and weather hazards reach peak intensity?
mature stage
Turbulence caused by obstructions, such as trees, building, mountains, ect
mechanical turbulence
______ icing combines the dangerous effects of both clear and rime icing conditions.
mixed
Turbulence intensity classification that changes in altitude and/or attitude occur but the aircraft remains in positive control at all times, and usually causes variations in indicated airspeed?
moderate (MDT)
Turbulence intensity classification that occupants feel defininte strains against seat belts or shoulder straps, unsecured objects are dislodged, and food service and walking are difficult?
moderate (MDT)
Which icing intensity classification has a rate of accumulation that even shorter encounters become potentially hazardous and use of de icing/ anti icing equipment or flight diversion is necessary?
moderate (MOD)
A condition in which pilots inflight are unable to maintain visual contact with mountain ridges is called
mountain obscuration
What is an atmospheric wave disturbance formed when stable air passes over a mountain?
mountain wave
What is a clous that forms in the rising branches of mountain waves?
mountain wave cloud
What can happen if an aircraft ingests volcanic ash?
partial or total power loss
Three factors that influence aviation safety include:
pilot ratings and experience aircraft design and performance specifications onboard equipment
A variable wind can be hazardous on takeoff and landing because it could ________
quickly become a crosswind or tailwind
What are the three types of precipitation which most commonly produce IFR weather?
rain drizzle snow
Which precipitation types most commonly produce instrument weather?
rain, drizzle, and snow
High density altitude _____ an aircraft's power and thrust.
reduces
What are the effects that high altitude can have on an aircraft performance?
reduces power and thrust longer takeoff and landing roll are required
Although _____ is the most common type of icing, it is the least serious because it is easier to remove.
rime
Rough, milky, opaque ice formed by the instantaneous freezing of small supercooled water droplets is what type if icing?
rime
What type of icing is the most common, but least serious type?
rime
What type of icing typically controlled by deicers/anti-icers, disturb the air flow, and its brittleness makes it easier to remove?
rime
What are three types of icing?
rime clear mixed
What cloud would provide visual proof that mountain wave exists? rotor TCU CB
rotor
Turbulence intensity classification that causes large, abrupt changes in altitude and/or attitude, usually causes large variations in indicated airspeen, and aircraft may be momentarily out of control.
severe (SEV)
Turbulence intensity classification that occupants are forced violently against seat belts or shoulder straps, unsecure objects are tossed about, and food service and walking are impossible?
severe (SEV)
Which icing intensity classification has a rate that de-icing/anti-icing equipment fails to reduce or control the hazard and immediate flight diversion is necessary?
severe (SEV)
Are smaller or larger aircraft affected more by tailwinds and crosswinds?
small
_________ is a line or narrow zone along which there is an abrupt change of wind direction.
sudden wind shift
What is liquid water at temperatures belwo the freezing point (0 degrees C)?
supercooled water
Why are light turboprops more susceptible to icing?
they typically fly at lower altitudes where temperatures often support icing
What stage during its lifecycle of a thunderstorm are updraft speeds of greater than 3,000 feet per minute exceed the climbing capability of most aircraft?
towering cumulus stage
What are the three distinct stages of a thunderstorm?
towering cumulus stage mature stage dissipating stage
_______ is wind that changes direction frequently.
variable wind
The most common cause of accidents is _____ when pilots feel like their environment is moving or spinning.
vertigo
______ are fine particles of rock powder that originate from a volcano
volcanic ash
When is convective turbulence most active?
warm summer afternoons when winds are light
Thunderstorm cell formation requires ___, unstable air, and lift.
water vapor
What three ingredients are needed for thunderstorm formation?
water vapor unstable air lifting mechanism(s)
The increase in _______ is insignificant compared to the ______ disruption caused by structural icing.
wieght, lift
A change in wind speed and/or direction in a short distance resulting in a tearing or shearing effect is called
wind shear
What generates turbulence between two wind currents of differing wind directions and/or speeds?
wind shear
