ATSC 113 Flying Midterm Exam Questions with All Correct Answers
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ATSC 113 Flying
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ATSC 113 Flying
ATSC 113 Flying Midterm Exam Questions with All Correct Answers
How does statically stable conditions affect flight - Answer- -forms near ground at night, clear skies, light winds
-non-turbulent
-oscillates as mountain-wave, drain into valleys, or form K-H turbulence waves
How does statica...
ATSC 113 Flying Midterm Exam
Questions with All Correct
Answers
How does statically stable conditions affect flight - Answer- -forms near ground at night,
clear skies, light winds
-non-turbulent
-oscillates as mountain-wave, drain into valleys, or form K-H turbulence waves
How does statically neutral conditions affect flight - Answer- -overcast, mod-strong
winds
-non-turbulent, but wind shear can change easily
-hitting mountain causes wake turbulence
How does statically unstable conditions affect flight - Answer- -sunny conditions with
light winds
-rising thermals = turbulent
-cumulus clouds if humidity high enough
What is CAPE (Convective Available Potential Energy) - Answer- measure of
accumulated buoyant energy of rising thermals
What is the K index - Answer- uses temperature and humidity/dew-point to indicate rain
intensity in thunderstorms
<20 = thunderstorms unlikely
20-30 = chance of sct. thunderstorms
30-40 = many likely, some heavy rain
>40 = many likely, very heavy rain
how do we determine stability - Answer- measure weather conditions at different
altitudes (sounding) using aircraft reports and rawinsondes (weather balloons)
,levels or turbulence (eddies) - Answer- small eddies: bumpy ride
medium eddies: pitch up and down, roll back and forth, and yaw left and right
large eddies: move whole aircraft
aircraft reaction to light turbulence - Answer- -slight turbulence and chop
-slight strain against seatbelts
-little/no difficulty walking
aircraft reaction to moderate turbulence - Answer- -change in altitude, still in control
-rapid chop
-strain against seatbelts
-objects dislodged
-difficulty walking
aircraft reaction to severe turbulence - Answer- -large, abrupt changes in
altitude/airspeed; momentarily out of control
-violently against seatbelts
-walking impossible
-objects thrown around
aircraft reaction to extreme turbulence - Answer- -impossible to control aircraft
-structural damage
-objects violently thrown around
what kind of turbulence is formed due to buoyancy/thermals - Answer- convective
turbulence, free convection, thermal turbulence
what kind of turbulence is formed due to different wind speeds/directions at diff.
altitudes - Answer- wind-shear turbulence, forced convection, or mechanical turbulence
what kind of turbulence is formed by wind hitting an object and flowing around it -
Answer- obstacle turbulence
wake turbulence (human made = aircraft wingtip vortices)
what is the Froude number (FR) - Answer- the ratio of natural wavelength to mountain
width (dimensionless)
, if the natural wavelength of air _________ the mountain width (W), then ____________
mountain waves occur - Answer- matches, the most intense
when Fr = 1
when _______ winds and ________ static stability occurs near mountains,
____________ will be created but not much ___________. - Answer- fast, weak, strong
turbulent wakes. mountain waves
when Fr = infinity
effect of mountain waves on flight - Answer- -experience chop (aircraft pushed up/down)
what kind of clouds form in layers of humid air near the altitude of mountain waves -
Answer- lenticular cloud (mountain wave cloud, or lee-wave cloud)
rotor clouds indicate severe turbulence
what is clear air turbulence (CAt) - Answer- wind shear turbulence outside of
thunderstorms
most intense near jet streams
also, Kelvin-Helmholtz waves (turbulence between layers of statically stable air)
might mistake CAT for convective turbulence near thunderstorms
what happens when clear air turbulence forms at altitudes with enough humidity -
Answer- form billow clouds (parallel cloud bands)
what is the atmospheric boundary layer (ABL) or planetary boundary layer (PBL) -
Answer- the bottom 300m to 4km layer of the atmosphere
grows thicker and stronger as sun heats up ground and causes thermals to rise
what is boundary layer turbulence - Answer- turbulence in the bottom 300m to 4km
layer of atmosphere near the ground
is boundary layer turbulence a hazard to aircraft, why? - Answer- not hazardous
often weak to moderate (weaker and sporadic at night with light winds)
supercooled droplets - Answer- unfrozen water at below freezing temperatures; freeze
instantly when touching cold and solid things; exist between temps of -40 to 0 Celsius
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