Landings Performance

Question 1

Landing objectives

Answer 1

To land in the shortest distance possible.
•Two Parts
•Descending Approach
•Ground Roll

Question 2

Descending approach

Answer 2

Minimum Safe Approach Speed
•1.3 Vso
•Transition to Vso at Touchdown

Steep Approach Angle
•Minimize Horizontal Distance

Question 3

Ground roll

Answer 3

Touchdown Speed (Vso)
•Slowest Airspeed Possible
•Just Above Stall
•CL = CLmax

Question 4

Newton’s second law

Answer 4

Acceleration (or Deceleration)
•Proportional to the Sum of Forces
•Inversely Proportional to the Mass of the Object

Question 5

Thrust

Answer 5

Thrust = 0
•Throttle At Idle
•May Not Be True

Question 6

Drag

Answer 6

•Induced & Parasite at Beginning
•Parasite at End
•Decreases As Velocity Decreases

Question 7

Friction

Answer 7

•Braking is Required to Land In Shortest Distance
Depends on
•Force Acting Normal to Runway
•Characteristic of Landing Surface
Characteristic of Surface
•Coefficient of Braking Friction (m)
•Increases As Velocity Decreases

Question 8

Minimize Vso

Answer 8

•Minimize Weight
•Slower Landing Speed
•Shorter Distance Required to Decelerate

•Maximize Air Density
•Low Altitude
•Low Temperature
•Slower Airspeed
Indicated Airspeed
•Stays the Same
True Airspeed
•Varies With Air Density and Altitude

•Maximize Surface Area & CL
Flaps
•High Lift
•Increase CLmax
•Same Amount of Lift at Slower Airspeed
High Drag
•Reduce Horizontal Velocity
•Increased Angle of Descent

Question 9

Maximize deceleration

Answer 9

Greatest Deceleration
•Negative Thrust
•Thrust Reversers
•Reversible Pitch Props
•Most Effective At Beginning of Landing Roll

•Increase Drag
•Aerodynamic Drag
•First Part of Landing Roll
•Wheel Braking Bigger Factor

•Increase Friction
•Coefficient of Friction
•Increase Weight
•Decrease Lift

Question 10

Increase friction

Answer 10

Increase Weight
•Heavier Airplane
•Greater Normal Force

Decrease Lift
•Spoilers

Question 11

Wind

Answer 11

Approach Ground Speed Reduced by Amount Equal to Headwind Component

Question 12

Runway slope

Answer 12

•Upslope - Retarding Force
•Downslope - Accelerating Force

Question 13

Approach speed

Answer 13

•Approach Speed 1.3Vso
•Higher Speed Increases Distance
•Distance = (velocity)2
Lower Speed
●Close to Stall
●Difficult to Control

Question 14

Flaps

Answer 14

•Allows Steeper Approach Angle Without Increase In Airspeed
•Reduces Total Landing Distance
•No Flap Approaches
•Higher Airspeed
•1.3 Vs1
Full Flaps
•High Lift
•High Drag
•Start of Ground Roll
•High Aerodynamic Drag
•Low Braking Friction
End of Ground Roll
•Low Aerodynamic Drag
•High Braking Friction

Question 15

Braking

Answer 15

Avoid Locking Brakes
•Reduces Braking Effectiveness
•Result in Blow Out
Avoid Landing With Brakes On

Question 16

Landing errors

Answer 16

Wheel barrowing – excessive speed, full flaps. Touchdown too fast, holds the airplane down with forward pressure.
Balloons – Thinks ground coming up too fast, pulls back.
Bounces – Too fast, or too great descent rate. Gains altitude as airspeed slows.
Porpoise – Touch nose gear, then mains, then nose gear, etc.