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.
Average deceleration on a dry runway using brakes and reversers is _____ kts per second.
7 knots per second
If you’re hydroplaning your deceleration is ______
With reversers it’s_____
1 knot per second or .05gs
3.8 knots per second
How can you shorten your ground roll after landing?
Brakes Aerodynamic Braking Thrust reversers Increase friction Speed Brakes
