Landing 323 Flashcards
What are the two parts of landing?
Descending Approach
Ground Roll
Descending Approach:
• L/D is an angle attack remember
• Minimum Safe Approach Speed
o 1.3 X Vso
o Transition to Vso at touchdown (NOT BEFORE)
• Steepest approach angle for your approach as possible.
o Reduce flare distance, minimize horizontal component of inertia
- Large increase in drag as aircraft pitches up
- As wing tip stalls on a swept wing, burbling flow misses the tail surfaces. There is no buffet.
- Airfoil center of lift moves inward and forward.
Newton’s Second Law:
• Newton’s Second Law : The direction of the force is the same as that of the acceleration.
After Touchdown:
Thrust
Drag
o Thrust = 0
♣ Throttle at idle after touchown
♣ Reverser makes thrust value = negative thrust
o Drag
♣ Induced and parasite at touchdown
♣ Parasite at end of roll
F =
F = MA
Aerodynamic drag decreases as _______ decreases.
Friction _______ as _____ decreases.
Aerodynamic drag decreases as velocity decreases.
Friction increases as velocity decreases.
• Acceleration and Deceleration
Proportional to
Inversely proportional to
o Proportional to the sum of all forces
o Inversely proportional to Mass of object
Friction
Depends on:
Characteristics of :
_________ ability
Product of _____ - _____
Friction: • Depends on forces acting normal to runway • Characteristics of landing surface • Braking ability • Product of Weight - Lift
How can you minimize landing distance:
Minimize stall speed
Maximize deceleration
How can you minimize Vso (4)
Minimize Weight
Maximize Air Density
Maximize surface Area & Cl
Flaps
Minimizing Vso in depth.
• Minimize weight –
o gives you a slower landing speed
o shorter distance to decelerate
• Maximize air density (not very easy to control)
o Low altitude
o Low temperature
♣ Slower airspeed.
• Maximize surface area & CL
o Maximize surface area (really only way is fowler flaps)
o Maximize Clmax
♣ Flaps
♣ Maximize flaps regardless of wind conditions
• Flaps
o High Lift Device
o Same amount of lift at slower speed
o Reduces horizontal component of inertia
o Increases angle of descent without increasing airspeed
How can you Maximize Deceleration?
Negative THRUST: WHAT DOES IT DO
o Provides approx. 40% of forward thrust
o Thrust reversers
o Reversible pitch props
Increases drag
♣ Aerodynamic Drag
Increases friction
♣ Max Wheel Braking
♣ Decrease Lift – spoilers, flaps up, etc.
♣ Anti-skid brakes
Other factors with Maximum Deceleration?
Wind
Runway Slope
Pilot Technique
o Wind
♣ Headwind component reduces groundspeed
o Runway slope
♣ Weight component
o Pilot Technique
♣ Approach Speed
♣ Use of flaps
♣ Use of Brakes
Landing Errors (4)
What happens and whY?
• Wheel Barrowing
o Excessive speed, full flaps. Touchdown too fast hold the airplane down with forward pressure.
• Balloons
o Thinks ground coming up too fast, pulls back
• Bounces
o Too fast, or too great descent rate. Gains altitude as airspeed slows
• Porpoise
o Touch nose gear, then mains, then nose gear.
Wind Shear:
Define it
How can you tell on final if there’s a shear layer?
Describe Horizontal Gusts
Describe Vertical Gusts
Falling air ______ angle of attack
Decrease in lift causes _______ to increase
- Any sudden change in the direction or speed of wind
- Watch wind sock and winds aloft if it’s drastic there’ll be shear
o Horizontal gusts (side to side gusts not crosswinds)
♣ Change in airspeed
♣ Induces a pitching moment to return to the airplane to trimmed speed
♣ Induces new drag and lift values for new airspeed
o Vertical Gusts ♣ Change Angle of attack ♣ May introduce damaging flight loads ♣ Rising gust increases angle of attack • Too many G’s • Stall ♣ Falling air decreases angle of attack • Decrease in lift - recovery altitude increases.
Beware during thunderstorms of _________.
Preventative measure?
Updrafts
Heat things up in case your air gets cold soaked especially since there’s liquid.
Problems with Ice
• Disturbs smooth airflow
• Adds weight
• Changes the shape of the airfoil
• Changes shape of control surfaces – flutter
• Increases stall speed
• Ice over air intake
o Both carbureted and fuel injected
• Any 90° bend in air intake plumbing
o Ice will form and build
• Windshield usually the first to notice ice
o Loss of visibility
o Probably indicates there’s developed ice elsewhere much greater
• Water seeps into wing or tail crevices and freezes at higher altitudes
o Loss of control
Carb Icing
How does it happen
Reduces what?
How do you fix it? (hopefully)
Carburetor Icing
• Air expands cools temperature
• Evaporation occurs cools temperature
• Reduces amount of airflow into the engine
Full carb heat always
• Partial heat may thaw moisture crystals, but not warm carb walls above freezing
• Carb air temp gauge
Snow
is it a problem? Why or why not?
What does it do to the aircraft?
What might you need to do while taxiing.
What does snow do?
SNOW • Generally not a problem o Already frozen moisture • Changes airfoil shape while sitting • May need to taxi with more power • Reduces visibility
Rain
Explain it all.
RAIN • Impact force o Pressure (density of air) + Force o Water is 1,000 x more dense than air o Wet airplane adds weight o Water rippling on wing surface increases rag up to 30% o Water logged – saturated air filter ♣ Power loss
Three types of hydroplaning.
Dynamic
Viscous
Reverted Rubber
Dynamic Hydroplaning
- (high speeds and a puddle of water)
- (water molecules can’t get out of the way fast enough and they don’t due to surface tension)
- high speeds +Standing water
Viscous Hydroplaning
• wet, painted surface of runway
Reverted Rubber Hydroplaning
Reverted Rubber
• locked brakes
• tire skidding generates enough heat to cause rubber in contact with runway to revert to it’s uncured state ( think of it as melting). Reverted rubber acts like a seal between tire and runway, delaying water exiting front eh tire footprint area. The water heats and is converted into steam which supports the tire off the runway.
