Flash Cards
What is cold soaking?
When cold fuel in the wings travels somewhere warm and humid, moisture builds on the wing and freezes
Dihedral
Wings that angle upwards in a V shape, more stable than flat
Anhedral
Wings than angle downwards, less stable (shaped like “A” for anhedral”
Slats
Small airfoils on leading edge of wing - help airflow at high AoA (“flaps” on front)
Wash out
When the angle of incidence is greater at the base than the tip (twisted out)
Geometric Pitch
The distance a propeller “should” move forward for one rotation
Wing Planform
The shape of the wing when viewed from above
Slats
Small airfoils on leading edge of wing - these increase camber (“flaps” on front)
Slots
Openings built into leading edge to allow air to pass through at high AoA
Spoiler
Airfoil on top of wing that destroys lift & laminar flow, used after touching down
Winglet
Vertical tip on the end of a wing that cancel vortices & decrease induced drag
Positive Stability
Becomes more and more stable (Ball in bowl)
Neutral Stability
Stays the same when moved (Ball on table)
Negative Stability
Becomes less and less stable (Ball on upside down bowl)
Static Stability
Becomes more stable or less stable in one direction
Dynamic Stability
Becomes more stable or less stable back & forth (overcorrecting)
Frise Ailerons
Help reduces aileron drag and adverse yaw by having the leading edge of the aileron below the trailing edge of the main wing (“Freeze” ailerons freeze the tendency for aileron drag)
Balance Tab
Like a trim tab, but automatically moves opposite the elevator control, think of it as a bit of added automatic trim to help the pilots required pressure
Mass Balance
Mass balances counteract flutter in dynamic controls
Torque
The plane’s tendency to rotate opposite the propeller on the longitudinal axis. Typically the propeller rotates clockwise from the pilots perspective causing the plane to bank and therefore yaw to the left (left turning tendencies!)
Slipstream
The air forced backwards from the propeller in the same direction as the propeller. This “snakes” around the plane, pushing the vertical stabilizer to the right (with a clockwise propeller and from the pilot POV) The plane is aerodynamically adjusted to help minimize this effect at cruise power & attitude, but at high power and low airspeed (climb) this force overpowers the adjustments made creating left yaw, and at a low power and high airspeed (descent) this adjustment is unnecessary, creating the opposite effect (right yaw)
Gyroscopic Effect
When the nose is moved in a specific direction it will turn slightly towards the movement that that side is moving towards. So if the propeller is spinning clockwise and the nose of the plane moves up, it will move slightly to the right, if it moves down, look at the direction the bottom of the prop is moving, left, so the nose will move slightly left. According to the law of precession, a force exerted on a spinning mass will cause a reaction 90 degrees along the direction of the rotation
Asymmetric Thrust (P-Factor)
At cruise, both blades of the propeller are taking the same “bite” of air (angle of attack), but when pitching up suddenly, the angle of attack of the right side increases while the left side decreases, causing more thrust on the right side causing a left yaw. (Look at a model propeller and pitch it up and down to understand) Changing this pitch downwards has the opposite effect (right yaw)
Variable Pitch Propeller
When climbing, a smaller propeller AoA (fine pitch) is more efficient, at cruise a larger propeller AoA (coarse pitch) is more efficient. Think of paddling a canoe when you start moving you need small strokes to get going, but once you’re moving big strokes are more efficient. Must know - Variable pitch props are therefore more efficient than fixed props. When a fixed pitch prop plane is pitched up the speed decreases, and the engine has a larger workload but is still putting out the same power, therefore RPM goes down. Variable pitch propellers have something called a “governor” that adjusts the pitch of the blade keeping the same RPM
Sweepback
When a wing is designed to be angled backwards, the relative airflow has longer to travel. This makes the camber seem stretched out and thus from the perspective of the relative airflow, the wing has less camber
Dynamic Balance Controls
A portion of the control surface that extends past the pivot point. Used to help plane controls feel lighter and easier to move
Indicated Horsepower vs Brake Horsepower vs Thrust horsepower
Indicated horsepower is the theoretical horsepower of the engine, brake horsepower is the actual horsepower of the engine accounting for friction and inefficiencies, thrust horsepower is the horsepower accounting for inefficiencies in the propeller and air resistance
What is the load factor at 30 degree angle of bank?
1.15 G
What is the load factor at 15 degree angle of bank?
1.04 G
What is the load factor at 45 degree angle of bank?
1.41 G
What is the load factor at 60 degree angle of bank?
2.0 G
What is the load factor at 75 degree angle of bank?
4.0 G
What is the stall speed in a turn equation?
Vst = Vs x square root of Load Factor
Longitudinal Stability is stability around which axis?
Lateral (aka pitch stability)
Lateral Stability is stability around which axis?
Longitudinal
Directional Stability is stability around which axis?
Vertical
When encountering birds straight ahead…
Climb above the birds. Do not fly under as their instinct is to dive
High Density-Altitude means the air is air is (more/less) dense?
Less dense (Seemingly high altitude)
Low Density-Altitude means the air is air is (more/less) dense?
More dense (Seemingly low altitude)
If humidity were to increase, air density would…
Decrease (Low density characteristics are HIGH/HOT/HUMID
Explain ground effect
Ground effect disrupts and cancels wing tip vortices, a type of induced drag. Less induced drag = better performance. Especially helpful for soft field takeoffs and increases with ground proximity
Best Rate of Climb is V__ , and its speed range for C172 is…
Vy, 68-78
Best Angle of Climb is V__ , and its speed range for C172 is…
Vx, 62-64
Maneuvering speed _________ with an increase in weight
Increases.
Vno is _________, and Vne is__________
Maximum Speed of Normal Operation (Top of Green Arc) and Speed to Never Exceed (Red Line)
Best Lift to Drag Ratio is also known as
Best Gliding Speed
Indicated Stall Speed vs True Stall Speed
Indicated stall speed never changes. It is a set number published in POH, true stall speed changes with altitude
How will an increase in density altitude change indicated airspeed and true airspeed
It will not change indicated airspeed, and it will INCREASE true airspeed
The Vno speed can be exceeded when…
The there is NO turbulence or poor weather, no wind shear etc
Which are considered a critical surface?
Any surface that produces LIFT
Ice accumulation with the thickness and roughness of a medium to coarse grit sandpaper will decrease the lift by as much as ___% while increasing the drag by as much as ___%
Lift by 30%, Drag by 40%
Grass runway increases ground roll takeoff by…
15% (GROUND ROLL ONLY)
Grass runway increases ground roll landing by…
45% (GROUND ROLL ONLY)
_______ knots of headwind reduces takeoff distance by _______%
How heavy is a gallon of fuel
A GALLON of fuel (not quart) is 7.5 Pounds
Civil Twilight is when the sun is ____ or more degrees below the horizon
6 or more
The minimum VFR fuel reserve at NIGHT is…
45 mins
Which instruments are connected to the static port and which are connected to the pitot tube?
Static port = Airspeed Indicator, Altimeter, and VSI
Pitot tube = Airspeed Indicator ONLY
If the Static Port is blocked, what will happen to the Airspeed Indicator, the Altimeter and the VSI?
If the Pitot Tube is FULLY blocked (including drain hole) how will the AI react?
What if the drain hole is not blocked?
- Altimeter will STOP MOVING - must know
-VSI will read zero
-Airspeed will under-read if you climb and over-read if you descend
- Altimeter will STOP MOVING - must know
- Airspeed Indicator will act like an altimeter
- Airspeed will read ZERO
- Airspeed Indicator will act like an altimeter
A Stall happens when…
The critical AoA is reached, and laminar flow is disrupted
As the G of G moves forward the stall speed _________. Why?
Increases (more likely to stall) This is because with a forward C of G the nose will be heavier, to keep it from dropping the pilot will need to pitch up slightly, increasing the AoA.
Bonus, in order to pitch up, downward force on the elevator is needed, acting as extra weight, further increasing stall speed
As the G of G moves aftward (back) the stall speed _________. Why?
Decreases (less likely to stall) Pilot will need to pitch the nose down to compensate, decreasing the AoA
Does a heavier C172 stall at a higher or lower speed
Higher. More weight means the pilot must pitch up to keep ALT, increasing the AoA
What should you do to your approach speed in GUSTY situations?
You are about to land. METAR reads 11G19 and you normally approach at 60KT. How fast are you going to approach?
Add 1/2 of the gust factor to approach speed
64KT (Gust Factor is 8, add 1/2 so 4 + 60)
The glass level containing the ball in the turn coordinator is called the…
Inclinometer
What is the formula to determine the bank angle needed for a 2 min standard rate turn
(KTAS / 10) + 7
The two errors of magnetic compasses are…
What does each error mean?
Deviation and Variation
Deviation is interference caused by
items within the plane including radios, magnets, and the plane itself
Variation is the discrepancy between True North and Magnetic North
What are the two main ways of heating the earths atmosphere? Define what each is.
Conduction and Radiation (terrestrial radiation)
Conduction = Heating of the air directly through warm terrain
Radiation = When UV from sun hits the ground and is transferred to terrestrial radiation which heats the air far more efficiently than UV. The higher the moisture, the larger the effect. And moisture is almost always higher closer to the earth
The atmosphere warms from…
A) the ground up
B) the top of the atmosphere down
A) the ground up
A matter change from solid to gas is called ______, and gas to solid is ______.
Sublimation, Deposition
4 ways to cause surface heating and 2 ways to cause surface cooling are?
Warm = Conduction, Radiation, Convection, Advection
Cool = Radiation Cooling, Cold air advection
The suns core is called, the next layer is, and the outer layer is…
Photosphere (Inner core)
Chromosphere (Middle layer)
Corona (Outer layer)
During either solstice, the sun is angle either north or south, how many degrees from the equator?
23.5 degrees (almost 24 like hours in a day)
How many degrees is the earth tilted?
23.5 degrees
What is a Rotor Cloud
A rolling, turbulent cloud below and leeward of a mountain peak, caused by a mountain wave
What is a Lenticular Cloud?
A cloud caused by a mountain wave at the peak of each wave where the moisture in the wave condenses due to altitude
Clouds typically associated with steady rain are called
Nimbostratus
What are the 4 cloud assosiatied with mountain waves?
Lenticular, Rotor, Cap, and Banner
To be in danger of icing what 2 conditions must be met?
Visible moisture and below freezing temp
Whaat are the 3 major types of aircraft ice?
Rime Ice = Small droplets instantly frozen on contact leaving air pockets in between (Lighter) and found primarily when encountering Stratiform clouds
Clear Ice = Larger droplets kept aloft by vertical currents, freeze slowly on aircraft leaving almost no air pockets (Heavier) and found primarily when encountering Cumuliform clouds
Mixed Ice = Most common, mix between Rime and Clear
What collects more ice in icing conditions? A large camber airfoil or a small camber airfoil
Small. This is because with a wider leading edge on the LARGE camber airfoil the air pushed forwards in front of the foil, pushes more of the incoming moisture out of the way
MAIN POINT: The thinner the surface, the less air it pushes out of the way, the more ice it will collect
What is the approximate range for critical angle of attack?
16 to 18 degrees
What are the 3 conditions that lead to a thunderstorm?
High humidity (high dew point) , Steep Lapse Rate, and a Lifting agent (convection, frontal lift, topographic lift etc)
Where do squall lines form in relation to a cold front
Well ahead of the cold
front
What is Virga
Rain that evaporates before touching the ground
What is the difference between mist and fog?
Mist is less intense than fog. Fog is less than 5/8SM visibility and mist is 5/8 or greater
What are the types of fog?
Radiation Fog, Advection Fog, Upslope Fog, Frontal Fog, Steam Fog, Ice Fog
How does frontal fog work?
Precipitation falls into colder air and saturates it
What is chop?
Slight rapid rhythmic bumps that do NOT change your altitude
Read the full words for all of these PIREP abbreviations
PIREP
UA
UUA
OV
TP
TM
FL
WX
TA
TB
IC
RM
SK
Pilot Report
PIREP
Urgent PIREP
Over (location) Ex. 36014 would be 14 miles north of…
Type of plane
Time
Flight level
Weather and visibility
Temperature
Turbulence
Icing
Remarks
Sky conditions
When are GFA charts released?
30 mins before each forecast period. Forecast periods are 00:00, 06:00, 12:00, and 18:00 UTC
What are the precipitation codes SG, PE, GS and GR?
SG = Snow Grains
PE = Ice Pellets
GS = Snow Pellets
GR = Hail (sounds like grail)
What are the obscuration codes BR, FU, SA and DU
BR = Mist
FU = Smoke
SA = Sand
DU = Dust
