Thrust PPL ground 9 stage 1

weather, meteorology

atmospheric levels

troposphere—surface to 36,000ft (most flights). only request higher to avoid clear air turbulence

tropopause

stratosphere—up to 160,000ft

mesosphere

thermosphere

what causes atmospheric circulation?

uneven heating of earth’s surface

(temp, convection, atmospheric pressure)

atmospheric pressure gradient is labeled with _____

isobars

closely spaced isobars = lots of ____

wind

atmospheric pressure is measured in inches mercury (Hg) or

millibars

mixed cold and warm fronts are called

stationary fronts

H and L on an atmospheric pressure map (surface analysis chart) means

high pressure and low pressure

low pressure moves

clockwise and up

high pressure moves

counterclockwise and down

Coriolis force is caused by

earth’s rotation

Coriolis force causes

ocean currents, curved flight paths.

Navigation at the _____ is the only place that doesn’t experience the Coriolis effect

equator

deviation due to the Coriolis effect is worst at the ___

poles

pressure gradient causes air to move from _____

whereas Coriolis force deflects it to the ______ in the northern hemisphere

high to low pressure, right

winds fly ______(perp/parallel) to isobars AT ALTITUDE (not at ground, due to surface friction)

parallel

at surface, winds cross isobars at ______(straight, angle), due to surface friction

angle

frictional force is felt within _____and it (increases/reduces) Coriolis force and moves toward (high/low) pressure

2000ft of ground, reduces, low

stability—define:

atmosphere’s resistance to vertical motion (turbulence)

adiabatic heating/cooling

change in temp of dry air during expansion or compression

standard lapse rate per 1000ft

2 celsius up to 36,000ft

if the lapse rate is lower than standard (ex. 1 degree celcius per 1000ft), the air is more/less stable?

more

temp inversions occur in stable/unstable air?

stable

temp inversion lids?

fog, haze, smoke, low clouds = cold layer right above,

warm layer on top, then cold air way higher

moisture changes?

evaporation, condensation, sublimation, deposition, melting, freeze

(sublimation = solid to gas, deposition = gas to solid)

relative humidity

actual amount of moisture in air compared to total amount that could be present at that temp

what determines relative humidity?

temp and dew point spread (less than 2 degree spread = fog, IFR)

explain frost

overnight, temp cools past its dew point,

water vapor condenses into dew-frost

explain clouds

air cools to its saturation point, droplets condense on condensation nuclei (ex. dust, salt)

a cloud near the surface is

fog

4 types of clouds

low, middle, high, vertical development

names of clouds

stratus = sheet

cumulus = puffy

cirrus = wispy, super high

nimbus = rain

cirrus clouds are made of ____ since they are so high. AVOID THEM ALL THE TIME!!! even when IFR rated. it’s like air gravel

ice crystals

low clouds

low clouds clouds that are 6,500ft AGL, stratus stratocumulus, nimbostratus

types of fog

Ice (uncommon)

Steam (sea coastline, cool air over moist warmth)

Upslope (moist, stable air up mountains)

Precipitation-induced (mist)

Radiation (flats surface, clear calm night)

Advection (sea coastline, warm air moving over cooler surface)

danger of upslope fog

where’d the mountain go? (mountain obscuration)

CFIT

controlled flight into terrain (plane crash)

middle clouds facts

6500-20000 AGL, altostratus, altocumulus

high clouds facts

above 20,000 AGL, cirrus, cirrostratus, cirrocumulus

clouds with vertical development facts

flat base, builds into towering cumulus or cumulonimbus, embedded thunderstorms in the middle. Very bad! Avoid!

supercooled water droplets

rain drops on your plane go into freezing weather conditions V

precipitation can disrupt wind in its ____ and ____

direction, velocity

virga

rain doesn’t reach the ground—hanging streaks of rain but super clear and dry ground. It happens due to strong force of drops coming down, causing evaporation

ice pellets and hail are associated with _______

temp inversions

precipitation induced fog

warm rain falls through a layer of cooler air

microbursts can be caused by

disappearing massive vertical development clouds—they fall in on themselves. Can kill you, and you won’t see it. Stay away from vert dev clouds

stay ___nm away from microbursts and thunderstorms

20

air masses share ___ and ____ properties

temp and moisture

stationary front

no movement, gloomy, can linger for 3-5 days

occluded front

cold and warm front merge. Cold moves faster to meet warm. Precipitation happens at warm front boundary as moisture in air is cooled

fast air is good or bad visibility?

good—fast air pushes particulates out of your way

precipitation always happens ____ and ___ a cold front

in front of and behind

warm front creates _____ clouds because it climbs up high and creates a condensed sheet

stratus (poor visibility)

fast moving cold front catches up with slow moving warm front

occluded front

cold occluded front

A cold front occlusion occurs when the cold front’s air mass is colder than the air mass in front of the slow-moving warm front. 

The cold air replaces the cool air and forces the warm front aloft into the atmosphere. 

warm occluded front

air ahead of the warm front is colder than the air of the faster-moving cold front.

When this occurs, the cold front “rides up” and travels over the warm front’s cold air mass

thunderstorms require what 3 things

unstable air, lifting force, high moisture

(MUU — moisture, uplifting, unstable)

cold front OVER DFW with a strong low pressure system results in

thunderstorms

low pressure system moves (up/down)

up

cold fronts are associated with ____ clouds and can become towering because cold fronts move (fast/slow)

cumulus, fast

air mass thunderstorm

scattered, common during afternoon

severe thunderstorm

wind gusts 50+kts, hail ¾ inch, tornado

single cell thunderstorm lasts

less than 1 hour

supercell and multicellular thunderstorms last

2+ hours

stages of thunderstorms

cumulus—updraft, vert dev. lifting cools air to dew point, condensing to water vapor

mature—beginning of precipitation, turbulent, most dangerous, up and down drafts

dissipating—predominately downdrafts, energy released and storm weakens

hail is formed by

circulating moisture going back up into the cloud every time it starts to fall.

T/F: hail only falls down

false! it has to go up to be made, so you might be hit from any direction. stay 20nm out

microbursts are associated with which stage of thunderstorm?

dissipating (last stage, getting rid of energy)

low level turbulence

below 15,000msl, due to uneven heating of earth’s surface

mechanical turbulence

obstacles interfere with normal wind flow (ex. apartment buildings)

convective turbulence

disturbed thermals

frontal turbulence is felt ahead of fast moving cold or warm front?

cold (warm is slow)

wake turbulence is worst at

heavy, clean, slow. most dangerous during light quartering tailwinds

how to avoid wake turbulence, 3 ways

stay above them, rotate before them, land after them

BBJ

Boeing business jet, private, same size as a 737 but only seats 20 people. Massive wake turbulence

CAT

clear air turbulence, high altitudes above 15000ft, caused by interaction of troposphere with tropopause and jet streams (channel of intense air)

airliners ride in the _____, which speeds up travel time

jet stream

mountain wave turbulence

stable air moving across a ridge. creates rotor clouds (rolling wave clouds) and lenticular clouds on peaks (looks like contact lens). AVOID the mountain area.

wind shear

change in windspeed/direction, associated with convective precipitation, jet stream, frontal zone or temp inversion. Any 15knot difference in wind is wind shear

what can detect wind shear?

windsock (erected then floppy), Terminal Doppler radar, low level wind shear alert system

microburst

1nm or less, no longer than 15 mins, downdrafts can be 6000ft per min, vert distance of 1000ft per less

icing can form as high as ___ degrees C ambient air due to Bernoulli’s principle (high velocity, low pressure, low temp)

5

icing feel like

autopilot pitch attitude slowly raising (struggling to maintain lift), stall speed increased, thrust/rpm performance reduced. Descend FAST so you don’t stall

clear ice

large supercooled water droplets or freezing rain that can’t freeze on impact. Blankets slowly back on the wing. DANGEROUS because heaviest, hard to remove, and hard to identify

rime ice

little supercooled droplets, freezes on impact and is opaque because it traps a little bit of air

mixed ice

combo of rime and clear

structural icing

clear, rime, and mixed ice on structure of aircraft

induction icing

carb icing due to Venturi effect and Bernoullis principle. could also form on air inlet. fix with alt air

how do you fix induction port or air inlet freezing?

pull alt air

instrument icing

pitot mass gets blocked, fix with pitot heat and alt static source (pulls ambient cabin pressure)

4 restrictions to visibility

haze—concentration of fine dry particles

smoke—suspension of combustion particles

smog—fog and smoke

dust—soil in air

volcanic ash is super _____ rock and can clog ______. It can pit the windscreen

highly abrasive, pitot static and ventilation system

3 types of meteorological reports?

airmet

sigmet

convective signet