Takeoff

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Cessna-Takeoff.png

Contents

[edit] Description

Every flight begins with a takeoff. Takeoffs are performed on a runway aligned with the wind. Depending on the conditions present, the pilot may use a number of techniques when taking off each flight.

[edit] Objective

At the completion of this lesson, the student will be able to identify and distinguish between the different types of takeoff; be able to identify when to use each method; know the difference between Vx and Vy; and know some common errors pilots make when performing these takeoffs.

[edit] Procedure

[edit] Normal Takeoff

Normal Takeoff
  • Used in light Wind or flying directly into the wind
    • Advantages of flying into the wind on takeoff
      • Takeoff at a reduced speed over the ground
      • Better climb performance (obstacle, noise abatement)
  • Look at the end of Runway for centerline
  • Check Runway number to compass
  • Feet on the floor, push rudder with toes
  • Smoothly advance power to full
    • Use Rudder pressure to stay on centerline
    • Check and Call "Engine Instruments Green"
      • Make sure engine isn't giving any abnormal indications
    • As aircraft accelerates, check and call "Airspeed Alive"
  • Gently pull Yoke back to rotate at Vr
  • You will need some right rudder during climbout for Torque Effect
  • Hold yoke pitch steady and aircraft will accelerate to Vy
  • Maintain Centerline

[edit] Crosswind Takeoff

Crosswind Takeoff
  • Used when the wind is not directly in line with the runway
    • Wind speed is 3 knots of x-wind or higher
  • Same procedure as normal takeoff with a few extras
  • Begin the takeoff roll with full aileron turned towards the wind
  • As the airplane accelerates, the controls become more effective
    • Less aileron needed
    • Use just enough aileron to keep the wing down
    • Use rudder to keep the nose aligned with centerline
    • As the airplane rotates, the upwind wheel leaves the ground last
  • For strong crosswinds, accelerate '1/2 Gust Factor' past Vr for controllability
    • Gust Factor = Wind speed with Gusts - Normal Wind speed
    • For example, Wind 280@10G16 has a Gust Factor of 6, so you would delay rotation speed until Vr + 3 knots
    • Smooth but 'very definite' liftoff
  • Upon takeoff, center the rudder and turn slightly into the wind
  • Use WCA to maintain centerline

[edit] Short Field Takeoff

VxVy.jpg
  • Maximum Performance Takeoff to clear a real or imaginary 'obstacle' at the end of the runway
  • Vx vs. Vy
    • The difference between Short field and normal takeoffs is the climb angle, which is useful for climbing over obstacles such as trees at the end of a runway. When an airplane climbs at Vx it will achieve this best angle.
    • Vx = most vertical distance per horizontal distance (Max Angle)
    • Vy = most vertical distance per amount of time (Max Rate)
  • Check the short field checklist
    • Typically uses flaps (to increase lift)
  • Taxi out to the beginning of the runway, leaving no wasted space
  • Full Power, Maximum braking
  • Check and Call "Engine Instruments Green"
  • Release Brakes
  • Check and Call "Airspeed Alive"
  • Rotate at Vr, Accelerate to Vx
  • When clear of obstacle, lower nose to Vy
  • Aircraft will accelerate
  • Raise flaps at the appropriate speed and continue climb at Vy

[edit] Soft Field Takeoff

Soft-Field-Takeoff.jpg

  • Soft Field takeoffs should be used on any surface that resists the forward motion of the airplane
    • Grass, mud, dirt, cracked runways, etc
    • Prevents nosewheel from getting caught and flipping airplane
    • Allows the wings to support the weight of aircraft as soon as possible
  • Ground Effect
    • When an aircraft is operated near the ground (within one wingspan), there are special changes to the airflow around the wings
    • This is called Ground Effect
    • The wingtip vortices that make up some of Drag are destroyed by coming into contact with the ground
    • This effect reduces Induced Drag and increases Lift for any Angle Of Attack
  • Taxi with yoke held back and minimum braking (rudder pressure only)
    • Real soft fields will require quite a bit of power to move the aircraft
  • 10 degrees of flaps when ready for takeoff
    • Why not earlier?
  • Smoothly apply full power when aligned with centerline
    • Nose will rise with downwash over the elevator
  • Allow the airplane to takeoff as soon as it is able, but CAREFULLY lower nose slightly to stay in Ground Effect
    • Forcing the airplane nose down may hit the nosewheel or prop and possibly flip the airplane
  • Airplane will accelerate in ground effect due to reduced drag
  • When Vx is reached, pitch for Vx/Vy
  • Raise flaps at the appropriate speed

[edit] Common Errors on Takeoff

[edit] Normal Takeoff Errors

  • Rough Handling of controls/power
  • Concentrating on instruments
  • Premature Liftoff
  • Holding airplane on ground past Vr
  • Coordination
  • Overcorrecting errors (chasing a/s,centerline)
  • Drifting off centerline

[edit] Crosswind Takeoff Errors

  • Not correcting for wind, or wrong direction
  • Side-Skipping
  • Drifting off centerline
  • Premature Liftoff

[edit] Short Field Takeoff Errors

  • Not using all available takeoff area
  • Premature Liftoff
  • Holding airplane on ground past Vr
  • Raising flaps too early
  • Not maintaining Vx until clear

[edit] Soft Field Takeoff Errors

  • Not enough back pressure
  • Climbing too steeply after liftoff
  • Abrupt control movement
  • Trying to climb out of ground effect too early
  • Allowing the airplane to return to the ground

[edit] Review

  • Compare the Normal Takeoff and the Short Field Takeoff
  • What is the primary concern during the Soft Field landing?
  • What type of performance would you expect during a Soft Field Takeoff?
    • Reduced performance, longer takeoff roll, consult AOM.
  • In a crosswind takeoff, how do we compensate for wind drift?
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