ATSC 113 MIDTERM EXAM 1 QUESTIONS WITH ANSWERS
2025/2026
Clear Air Turbulence & Sucker hole - Severe turbulence in clear air.
A gap of clear air btw TS w/ severe turbulence is "sucker hole".
Downbursts - Rapidly descending air, found below clouds that have precipitation or
virga (evap before hitting the ground). Smaller diameter & shorter duration are called
microbursts.
Gust fronts - When cold downburst hits the ground -> radial straight-line winds. The
leading edge is gust front.
May lead to low-level wind shear, aircrafts may climb higher/lower than glidescope
(descending path). Pilots may fly fast, go around, or do a holding pattern.
If enough moisture -> arc cloud.
In dry conditions -> haboob (wall of dust), touches the ground whereas arc cloud
doesn't.
Hailstone - ice balls >0.5cm in diameter that falls from TS. The dmg path is hail swath
(giant hail 5cm>x>1.9cm, graupel <0.5cm)
Terminal fall V increases with size.
Large hailstones form if updraft speed > Terminal fall V (i.e. supercell).
Hail falls closest to the main updraft -> hail shaft.
Tornadoes - Violently rotating columns of air btw TS, clouds, and ground. Tornado
funnel often vis from cloud droplets or dirt.
Enhanced Fujita scale relates tornado dmg intensity to rotational speed.
What is the hazard associated with rain? - Reduced visibility. However, ingestion of
heavy rain into turbine engine can cause it to stop.
Clear ice vs Rime ice - Clear ice: slow freezing of large raindrops -> relatively clear (or
dark), hard, difficult to remove.
Rime ice: smaller cloud droplets freeze instantaneously, traps air pockets, brittle.
*supercooled droplets can be liq 0C to -40C.
Deicing vs anti-icing - Deicing removes ice (i.e. pneumatic boots, antifreeze/chemical,
carburator heat control).
Anti-icing prevents ice formation (i.e. jet exhaust duct, electric heater, carburator heat
control).
PIREPS of ice - pilot reports on icing intensity.
*Trace - perceptible
Light - problematic if prolonged
Moderate - short encounters may be dangerous
Severe - deicing/anti-icing fail
,Lightning - Long, thin spark created in TS. Can be btw cloud & ground, 2 clouds, within
a cloud, cloud to air.
Forms from collision of small ice crystals & hailstones (graupels)
Small ice crystals (+) carried to the top of TS by updraft to anvil while larger graupel (-)
towards bot as they fall.
When the voltage dif. is big enough, insulative air ->ionized, conductive. Greater build
up of voltage = longer lightning
P-static - Sparks on the outside of aircraft from contact with uncharged particles and (-)
builds up on the surface.
(St. Elmo Fire = corona discharge as filaments of light writhing on the outside).
Cumuliform clouds - Warm humid air rising through cooler surrounding air. Strong
updrafts.
S - Cumulus humilis
M - Cumulus mediocris
L - Cumulus congestus
XL -Cumulonimbus/TS
Happens when air near ground is colder than the ground (clear day w/ sunshine).
Happens behind cold front. *btw updrafts are weaker downdrafts of clear air. downdraft
causing wind gusts leading to darker patches of water = "cat's paws"
Stratiform clouds - Warm air slides up along cold air. Seen ahead of warm front. Not
usually turbulent but may have supercooled liquid.
H - Cirrus, Cirrostratus, Cirrocumulus
M - Altostratus, Altocumulus
L - Stratus, Nimbostratus
It goes H - M - L (w/ light rain or snow) in sequence.
Stratus vs Nimbostratus - Nimbo (diffuse) precipitating while Stratus is not (well
defined).
Castellanus - Special cloud
Look like small castle turrets, sign of atm becoming unstable, TS possible later. Cloud
diameter similar to height.
A thin cold air layer above warm air -> warm air rises -> warm-cold-air sandwich ->
castlellanus, a type of stratiform cloud.
Convective circulations do not touch the ground, contained in warm-cold air sandwich.
Racist Joke - A black Jewish boy runs home from school one day and asks his father,
"Daddy, am I more Jewish or more black?" The dad replies, "Why do you want to know,
son?" "Because a kid at school is selling a bike for $50 and I want to know if I should
talk him down to $40 or just steal it!"
Yomama Joke - Yo mama so stupid, she sold her car for gas money.
, Billow (Kelvin Helmholz Waves) clouds - Indicative of wind shear & CAT, smooth air
often above or below.
Wind shear causes waves in a cooler layer under warmer air. Short wavelength, thin
waves.
Parallel bands of clouds form at each crest of waves only when rising cool air is humid.
Associated with unstable air along with castellanus.
Lenticular (Mt-wave) Cloud - Indicates vertical wind oscillation & possible Mt wave
turbulence. Wind hits Mt -> rises and comes back down, overshoots due to inertia ->
rises again.
In the upward portion, air cools -> cloud. When it descends, cloud evap. Clouds appear
stationary -> "standing lenticular". First wave over Mt = "Cap Cloud"
Rotor Clouds - Turbulent clouds that form under crest of Mt waves.
Rotate about a horizontal axis parallel to Mt range. Associated w/ strong turbulence &
violent up/down drafts. Change in wind direction over short distance makes flying
extremely dangerous.
Banner Clouds - Mt. special cloud along with lenticular & rotor clouds.
Forms on downwind side of Mt. Wind causes low P on the other side of the Mt peak,
sucking up lower alt air -> vapour condenses to clouds.
Pyrocumulus & Pileus - Pyrocumulus: forest fires & volcanoes, heat & moisture may
lead to TS.
Pileus: Form over fast-growing cumulus clouds, harmless, shore-lived til cumulus rises
through.
Fractus clouds - Low-alt, ragged cloud aka scud. Indicates high humidity and strong
wind at low alt. Forms when; (1) rain falls into cloud-free air -> evaporates ->
recondenses into cloud (if cloud touches ground = precipitation fog). (2) humid, cool air
near ground lifted up by turbulence to lifting condensation level -> clouds form.
Clouds formed by extra heat, updraft, turbulence - Pyrocumulus, Pileus, Fractus clouds
Man-made clouds - Fumulus - clouds over cooling towers.
Contrails - Aircraft condensation trails, formed from water vapor from jet engines, drawn
into wingtip vortices, indicate strong wake turbulence.
Cross Winds & Tail Winds & Head Winds - Tail winds are good for travel but bad for
take-off/landing.
Crosswinds can be compensated by crabbing but bad for take-off/landing.
Try to land/take-off on a runway w/ # closest to wind direction for a headwind (i.e. 14 =
135o).
2025/2026
Clear Air Turbulence & Sucker hole - Severe turbulence in clear air.
A gap of clear air btw TS w/ severe turbulence is "sucker hole".
Downbursts - Rapidly descending air, found below clouds that have precipitation or
virga (evap before hitting the ground). Smaller diameter & shorter duration are called
microbursts.
Gust fronts - When cold downburst hits the ground -> radial straight-line winds. The
leading edge is gust front.
May lead to low-level wind shear, aircrafts may climb higher/lower than glidescope
(descending path). Pilots may fly fast, go around, or do a holding pattern.
If enough moisture -> arc cloud.
In dry conditions -> haboob (wall of dust), touches the ground whereas arc cloud
doesn't.
Hailstone - ice balls >0.5cm in diameter that falls from TS. The dmg path is hail swath
(giant hail 5cm>x>1.9cm, graupel <0.5cm)
Terminal fall V increases with size.
Large hailstones form if updraft speed > Terminal fall V (i.e. supercell).
Hail falls closest to the main updraft -> hail shaft.
Tornadoes - Violently rotating columns of air btw TS, clouds, and ground. Tornado
funnel often vis from cloud droplets or dirt.
Enhanced Fujita scale relates tornado dmg intensity to rotational speed.
What is the hazard associated with rain? - Reduced visibility. However, ingestion of
heavy rain into turbine engine can cause it to stop.
Clear ice vs Rime ice - Clear ice: slow freezing of large raindrops -> relatively clear (or
dark), hard, difficult to remove.
Rime ice: smaller cloud droplets freeze instantaneously, traps air pockets, brittle.
*supercooled droplets can be liq 0C to -40C.
Deicing vs anti-icing - Deicing removes ice (i.e. pneumatic boots, antifreeze/chemical,
carburator heat control).
Anti-icing prevents ice formation (i.e. jet exhaust duct, electric heater, carburator heat
control).
PIREPS of ice - pilot reports on icing intensity.
*Trace - perceptible
Light - problematic if prolonged
Moderate - short encounters may be dangerous
Severe - deicing/anti-icing fail
,Lightning - Long, thin spark created in TS. Can be btw cloud & ground, 2 clouds, within
a cloud, cloud to air.
Forms from collision of small ice crystals & hailstones (graupels)
Small ice crystals (+) carried to the top of TS by updraft to anvil while larger graupel (-)
towards bot as they fall.
When the voltage dif. is big enough, insulative air ->ionized, conductive. Greater build
up of voltage = longer lightning
P-static - Sparks on the outside of aircraft from contact with uncharged particles and (-)
builds up on the surface.
(St. Elmo Fire = corona discharge as filaments of light writhing on the outside).
Cumuliform clouds - Warm humid air rising through cooler surrounding air. Strong
updrafts.
S - Cumulus humilis
M - Cumulus mediocris
L - Cumulus congestus
XL -Cumulonimbus/TS
Happens when air near ground is colder than the ground (clear day w/ sunshine).
Happens behind cold front. *btw updrafts are weaker downdrafts of clear air. downdraft
causing wind gusts leading to darker patches of water = "cat's paws"
Stratiform clouds - Warm air slides up along cold air. Seen ahead of warm front. Not
usually turbulent but may have supercooled liquid.
H - Cirrus, Cirrostratus, Cirrocumulus
M - Altostratus, Altocumulus
L - Stratus, Nimbostratus
It goes H - M - L (w/ light rain or snow) in sequence.
Stratus vs Nimbostratus - Nimbo (diffuse) precipitating while Stratus is not (well
defined).
Castellanus - Special cloud
Look like small castle turrets, sign of atm becoming unstable, TS possible later. Cloud
diameter similar to height.
A thin cold air layer above warm air -> warm air rises -> warm-cold-air sandwich ->
castlellanus, a type of stratiform cloud.
Convective circulations do not touch the ground, contained in warm-cold air sandwich.
Racist Joke - A black Jewish boy runs home from school one day and asks his father,
"Daddy, am I more Jewish or more black?" The dad replies, "Why do you want to know,
son?" "Because a kid at school is selling a bike for $50 and I want to know if I should
talk him down to $40 or just steal it!"
Yomama Joke - Yo mama so stupid, she sold her car for gas money.
, Billow (Kelvin Helmholz Waves) clouds - Indicative of wind shear & CAT, smooth air
often above or below.
Wind shear causes waves in a cooler layer under warmer air. Short wavelength, thin
waves.
Parallel bands of clouds form at each crest of waves only when rising cool air is humid.
Associated with unstable air along with castellanus.
Lenticular (Mt-wave) Cloud - Indicates vertical wind oscillation & possible Mt wave
turbulence. Wind hits Mt -> rises and comes back down, overshoots due to inertia ->
rises again.
In the upward portion, air cools -> cloud. When it descends, cloud evap. Clouds appear
stationary -> "standing lenticular". First wave over Mt = "Cap Cloud"
Rotor Clouds - Turbulent clouds that form under crest of Mt waves.
Rotate about a horizontal axis parallel to Mt range. Associated w/ strong turbulence &
violent up/down drafts. Change in wind direction over short distance makes flying
extremely dangerous.
Banner Clouds - Mt. special cloud along with lenticular & rotor clouds.
Forms on downwind side of Mt. Wind causes low P on the other side of the Mt peak,
sucking up lower alt air -> vapour condenses to clouds.
Pyrocumulus & Pileus - Pyrocumulus: forest fires & volcanoes, heat & moisture may
lead to TS.
Pileus: Form over fast-growing cumulus clouds, harmless, shore-lived til cumulus rises
through.
Fractus clouds - Low-alt, ragged cloud aka scud. Indicates high humidity and strong
wind at low alt. Forms when; (1) rain falls into cloud-free air -> evaporates ->
recondenses into cloud (if cloud touches ground = precipitation fog). (2) humid, cool air
near ground lifted up by turbulence to lifting condensation level -> clouds form.
Clouds formed by extra heat, updraft, turbulence - Pyrocumulus, Pileus, Fractus clouds
Man-made clouds - Fumulus - clouds over cooling towers.
Contrails - Aircraft condensation trails, formed from water vapor from jet engines, drawn
into wingtip vortices, indicate strong wake turbulence.
Cross Winds & Tail Winds & Head Winds - Tail winds are good for travel but bad for
take-off/landing.
Crosswinds can be compensated by crabbing but bad for take-off/landing.
Try to land/take-off on a runway w/ # closest to wind direction for a headwind (i.e. 14 =
135o).
