PPL Skills - Take-off and climb

Contents

 ERAU Video on take-offs

Normal takeoff and climb  

Before the takeoff: 
  • First ensure you have gone through all the relevant pre-flight and pre-takeoff checklists
  • Consult the POH and ensure that the aircraft is capable of making the takeoff given the current weather conditions, altitude of the airport, weight, runway length, etc. 
    • High temperatures and altitudes decrease aircraft performance
  • Announce your intentions on the CTAF (if non-towered), or request clearance from ATC
  • Observe proper separation between yourself and other aircraft taking off, particularly larger ones, to prevent being affected by wake turbulence
  • Find visual references that line up with the extended runway centreline to align yourself on the climb out
  • Remember to verify you are on the right runway. Call out the runway number, followed by "verified" as a self-check
 The takeoff roll:
  • Align yourself with the centreline 
  • Apply power smoothly 
    • Abrupt application of power may exacerbate the left-turning tendencies and cause the aircraft to be harder to control
    • May also cause damage to the engine 
  • Continue to monitor instruments 
    • Airspeed indicator comes alive (will not indicate airspeed below a certain threshold)
      • Call out "airspeed alive"
    • Engine parameters normal 
      • RPM
      • Oil temp / pressure
  • Use the rudder pedals to correct for the left-turning tendencies
    • Do not use the brakes to keep the aircraft centred
  • As air resistance increases, controls become more effective
    • As the elevators also come "alive" - control yoke moves aft as the elevators rise
  • As forward momentum builds, less and less rudder input is needed to keep the aircraft centred
  • Keep the visual references picked earlier in sight 
  • Avoid over-controlling the aircraft 
Lift-off:
  • Memorise the important speeds for the aircraft you're flying
    • For the Cessna 172, pitch up at 55kts and climb out at about 75-80kts (Vy is 79kts)
  • If the aircraft is properly trimmed, just hold the aircraft at the appropriate attitude and it will climb at the appropriate climb out speed without the need for any further trim 
    • For the Cessna 172, hold the nose at about a 7.5-degree nose-up pitch
    • Remember to release back pressure (on the stick) once the right speed has been achieved
  • It is good to step on the brakes after lift-off to stop the wheels from spinning, which may cause vibrations 
  • Maintain wings-level attitude 
  • Do not be fixated on the airspeed 
    • Just hold the nose-up pitch attitude and the aircraft will stabilize at the right climb speed (as long as it was properly trimmed) 
  • In gusty conditions (when wind is not stable), might want to maintain a 10-knot margin in case the wind suddenly decreases (resulting in a sudden loss in airspeed)
Initial climb-out:
  • Once positive rate, retract the flaps and landing gear (if equipped)
  • Maintain wings-level attitude and correct for left-turning tendencies using right rudder and aileron input
  • Maintain take-off power until at least 500ft above surrounding obstacles
  • Once at a comfortable altitude, you should decrease pitch and increase airspeed to higher than Vy
    • This is known as cruise climb or enroute climb 
    • Increased airspeed helps to cool down the engine (particularly in air-cooled aircraft like the skyhawk)
    • A re-trim of the aircraft is then necessary
    • Remember not to chase the instruments
  • At some airports, there may be noise abatement rules. These are usually printed on the airport charts but if unfamiliar, clarify with ATC

Crosswind take-offs and climbs
  • Check windsock before take-off
  • Similar to taxiing into a headwind, you should "turn into the wind" to prevent the upwind wing from being lifted up by the crosswind
  • Begin the take-off roll at full deflection and gradually decrease the aileron input as the aircraft accelerates
    • Continue to maintain aileron deflection 
    • If the upwind wing is allowed to rise, it may cause the aircraft to "skip" downwind, which may cause structural damage to the landing gear
  • Aircraft tend to yaw into the wind, due to the effect of the wind hitting the rudder which presents a large surface area to a crosswind 
    • This affects the amount of rudder input the pilot might need to make to correct for left-turning tendencies
  • During lift-off, as the ailerons are deflected, one wheel will lift off the ground before the other  
  • As the climb is established, turn the aircraft into the wind enough to maintain alignment with the extended runway centreline (known as crabbing - the aircraft maintains a certain direction despite not actually pointing in that direction)
  • Direction and intensity of crosswind may vary over altitude so continual correction is needed

Ground Effect:
  • Wings work partially by deflecting air downwards. When the aircraft is close to the ground, you can imagine that the air below the wings is compressed. Imagine the aircraft riding on a wave of air!
  • Improved performance felt at very low altitudes, up to about a wingspan from the ground
  • The proximity of the ground disrupts upwash, downwash, and wingtip vortices (which is also responsible for wake turbulence)
    • Less wingtip vortices = less induced drag 
      • At low speeds, induced drag is much more significant (at higher speeds parasite drag is more significant) 
    • There is an increase in local static pressure 
      • Causes airspeed indicators and altimeters to indicate a lower airspeed and the vertical speed indicators to indicate a descent
      • Reduction in stall speed 
  • Affects low-wing aircraft more than high-wing aircraft
  • Some pilots make use of the ground effect to lift off earlier, accelerate to climb speed, and climb away
  • As the aircraft lifts off from the ground effect area
    • Drag and therefore thrust required increases
    • Airplane experiences a pitch-up tendency as the downwash increases near the horizontal stabilizer 
    • Indicated airspeed increases 


Common errors:
  • Not clearing the area before taxiing onto the runway 
  • Failure to review POH performance charts before takeoff 
  • Abrupt use of the throttle 
  • Failure to check engine instrument for signs of malfunction during the take-off roll
  • Failure to anticipate the aircraft's left-turning tendencies
  • Relying solely on the airspeed indicator
  • Failure to obtain proper lift-off attitude 
  • Inadequate compensation for P-factor and torque resulting in a side-slip
  • Overcontrol of elevators
  • Lack of elevator trimming
  • Allowing left wing to drop on initial climb-out
  • Failure to attain and maintain Vy


Short-Field Take-Offs and Landings

  • Basic idea: minimise drag to accelerate to Vx as soon as possible, and use Vx for the initial climb out.
  • Precise manipulation of the control surfaces is required to attain the maximum performance
  • Consult the POH to find out the manufacturer's recommended configuration
    • 10-degree flaps for C172
  • Have a good understanding of Vx and Vy speeds and know what these speeds are for your aircraft 
  • Get familiar with the amount of trim your aircraft needs in different situations - different loads, centres of gravity, and Vx vs Vy climbs
    • Since Vx is slower than Vy, more nose-up trim should be applied than a standard take-off
  • Begin right at the beginning of the runway, configure everything as necessary before starting the roll
  • Goal is to maintain as little drag as possible 
    • In taildraggers, get the aircraft parallel to the ground as soon as practical 
    • In tricycle wheel aircraft, little elevator manipulation is required
  • Rotate and climb out at Vx
  • Vx speed varies with weight and other conditions
    • Verify with POH before you begin your take-off
  • Do not fall below the Vx speed, as it will just result in a shallower climb, even if raising the nose is the intuitive thing to do
  • Be familiar with the pitch attitude that corresponds to the respective speed
    • In a C172, maintain about a 11-12 degree nose-up pitch attitude to achieve Vx.
  • Some aircraft have a tendency to lift-off before Vx speed (ground effect)
    • Reduce pitch attitude to maintain level flight until Vx is achieved
    • Better than forcing the aircraft to remain on the ground
  • Flaps and landing gear should remain in position until clear of obstacles
  • Accelerate to Vy once 50ft AGL, or clear of obstacles (if higher than 50ft AGL)
Common mistakes: (specific to short-field operations)
  • Raising flaps and landing gear prematurely 
  • Rotating too early - excessive drag 
  • Exerting nose-down pressure to force the aircraft to remain on the ground until Vx
  • Insufficient rotation - aircraft speeds up past Vx


Cessna 172SP POH:



Soft-Field Take-Offs

  • Basic idea: minimise drag from grass, uneven surface by increasing lift. 
  • Transfer the weight of the aircraft from the wheels to the wings as soon as possible 
    • Make use of the ground effect 
    • Raise flaps (as per POH recommended config)
    • Relatively high angle of attack (increased lift) 
  • Do not stop on the runway after lining up to avoid getting bogged down 
  • Attain the nose-up pitch attitude early (even before safe climb speed) so as to increase lift and allow the aircraft to start lifting off
  • Once airborne, gently reduce pitch to attain normal safe climb speed
  • Bear in mind that a premature or low-speed climb may cause the aircraft to settle back down to the runway (ground effect)
    • Avoid climbing until at least Vx is attained
  • If the airfield is wet / muddy / slushy, you should not retract the landing gear too soon but instead let the airflow clean the landing gear


Rejected take-offs / engine failure on take-off

  • A point should be picked along the runway before which a safe stop can still be conducted 
    • On more advanced aircraft, the V1 speed indicates the speed before the aircraft can still be stopped safely. It is therefore sometimes known as the "commit to fly" speed.
  • If the engine needs to be stopped due to engine failure, the magnetos should be turned off and fuel mixture be set to idle cutoff. 
  • If the engine failure occurs on the initial climb out:
    • The pilot should pitch down to avoid stalling
      • Maximum distance (which may be more useful in getting to a suitable landing spot) vs maximum time aloft (which may be more useful in picking a good landing spot)
      • Maximum distance is achieved only at the best glide speed - 68kts for the C172SP
    • Reduce right rudder input to maintain coordinated flight
    • Land at the best available spot (and not attempt to turn around unless sufficiently high)
Cessna 172SP POH:

Personal Takeaways

  • Check how conditions affect take-off performance of the aircraft, as per the POH
  • Remember to clear the area before taxiing onto the runway
  • Less rudder input required as aircraft accelerates 
  • Can be more smooth with the throttle 
  • Monitor engine parameters 
  • Pick visual references to line up with after taking off to maintain extended centreline 
  • Lift off at a higher speed in gusty conditions 
  • Step on brakes after lift off
  • Ground Effect 

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