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Crosswind Approach & Landing

Introduction:

  • Landing is the most dangerous phases of flight, as it is in a terminal area when the pilot is most likely to be fatigued and concentrating on the "get-there-itis"
  • The goal of a crosswind landing is to safely and accurately establish and maintain a stabilized approach to landing, correcting for a crosswind during the approach, touchdown, and roll out
Crosswind Component Chart
Figure 1: Crosswind Component Chart
Heading Indicator Crosswind Rule-of-Thumb
Figure 2: Heading Indicator Crosswind Rule-of-Thumb
Heading Indicator Crosswind Rule-of-Thumb
Figure 3: Light Aircraft Association - Crosswind Calculations Made Easy
Heading Indicator Crosswind Rule-of-Thumb
Figure 3: Light Aircraft Association - Crosswind Calculations Made Easy

Determining Crosswind Component:

  • Crosswinds can be determined through a number of methods which each serve a purpose, depending on the phase of flight
  • When calculating the crosswind always use the full gust component meaning, calculate crosswind as a "worst case" scenario
  • Chart Method:

    • Crosswind charts can be found in nearly every POH/PIM but are not aircraft specific, so any will do
    • Using the example provided in [Figure 1], plot your point using the number of degrees off the runway heading, at with the full gust component as strength
      • Lets say we're going to land at runway 360 and the wind is coming from 020 at 20 knots
      • We'll plot the wind strength at the 20° radial line (representing 20° off the runway) on the 20° point (representing the wind strength)
      • From that point we plotted we can move straight left for the headwind component: roughly 19 knots
      • We can also move straight down for the crosswind component: roughly 6 knots
  • Heading indicator rule of thumb:

    • Find the reported wind direction on the outside of the DI (shown as a large blue arrow). You now have the first piece of information; the wind is from the right [Figure 2/3]
    • Mentally drop a vertical line down from the wind direction on the outside of the DI to the horizontal centerline (shown in blue)
    • The horizontal center line (red) represents the crosswind axis so visually scale-off the crosswind component as a proportion of the length of the crosswind axis, ie, the wind speed
      • Using our example this means our crosswind component is just less than 20 knots (mathematically the answer is 19 knots)
  • Sixths Rules of Thumb:

    • If angle = 10 deg then crosswind component = 1/6 wind strength
    • If angle = 20 deg then crosswind component = 2/6 (1/3) wind strength
    • If angle = 30 deg then crosswind component = 3/6 (1/2) wind strength
    • If angle = 40 deg then crosswind component = 4/6 (2/3) wind strength
    • If angle = 50 deg then crosswind component = 5/6 wind strength
    • If angle = 60+ deg then crosswind component = wind strength
  • Additional methods:

    • Additional methods of calculating crosswind component exist however, they may not be as prudent for use during approach and landing as they would for other phases of flight, such as takeoff
    • They include:
Airplane Flying Handbook, Figure 8-16. Side-slip Approach
Figure 4: Airplane Flying Handbook, Side-slip Approach
Figure 5: Airplane Flying Handbook, Crabbed Approach

Crosswind Compensation Techniques:

  • Slip:

    • A slip is a cross-control procedure where you are using "wing-low, top-rudder" to track the aircraft straight for the purposes of altitude loss (forward-slip) or crosswind compensation (side-slip)
      • In doing this, you will need to lower the nose as the increase in drag without an increase in thrust will cause a rapid loss of airspeed risking a stall
      • Simply stated, the higher the angle of bank, the lower the nose must be
    • Forward-slip:

      • A forward slip is used to increase the aircraft’s rate of descent without increasing airspeed in the process
      • The pilot accomplishes a forward slip by hanging as much of the fuselage (increasing drag) in the breeze as possible
      • This increase in drag bleeds energy
      • Assuming that the runway is properly lined up, the forward slip will allow the aircraft track to be maintained while steepening the descent without adding excessive airspeed
      • This is accomplished by applying full rudder and utilizing the angle of bank to maintain a ground track
      • Since the heading is not aligned with the runway, the slip must be removed before touchdown to avoid excessive side loading on the landing gear, and if a crosswind is present an appropriate side slip may be necessary at touchdown as described below
      • Using the maximum amount of rudder deflection possible will create only one variable (the aileron)
    • Side-slip:

      • A side-slip is used to compensate for a crosswind on final approach
      • First you apply aileron into the wind to compensate for the crosswind blowing you off centerline
      • Next you use the rudder to maintain alignment with the runway centerline
      • The horizontal component of lift forces the airplane to move sideways toward the low wing
      • The aircraft's rudder is used to align to center while the wings are dripped (toward the wind) to maintain track (drift)
      • Held all the way to touchdown, this will result in the low side wheel touching down first, followed by the high wheel, and lastly the nose/tail wheel
      • Note that when performing a slip, the Pilot Operating Handbook may impose certain restrictions such as:
        • Avoiding slips with full flaps
        • Avoiding slips for prolonged periods of time which may result in fuel ports becoming uncovered
        • Airspeed indications may vary due to static ports receiving direct wind
          • If your static port is located on the left side of the fuselage, a slip using right rudder will cause the perceived static pressure to be higher than actual as ram air is forced into the static port, resulting in your indicated airspeed being less than actual. Therefore, it would normally be advisable to maintain an airspeed comfortably within the middle range of the white arc (flap operating range) to avoid being either too close to a cross-control stall or a flap over-speed condition
  • Crab:

    • Coordinated flight whereby you are pointing the nose of the aircraft upwind enough to keep the airplane's ground track straight
    • The angle by which the aircraft is flying relative to the runway is considered the crosswind correction
    • It is most preferable, in general aviation, to fly a crab and transition to a slip for landing to avoid side-loading the landing gear
    • At some point during the final approach, a transition from crab to sideslip for the landing flare and touchdown should be made

Gust Factor:

  • On all approaches, but especially crosswind approaches, you'll want to determine the gust factor
  • Gust factors are agnostic to the wind direction
  • To calculate, take your gusts and subtract them from the sustained wind
    • If your wind is 10 knots and the gusts are to 20 then we can subtract 20 from 10 to get 10 as our gust factor
  • On approach we'll want to add half of the gust factor to our approach speed in order to create a margin of safety within a gusty environment

WARNING:
All procedures here are GENERALIZED for learning.
Fly the maneuver in accordance with the Pilot Operating Handbook (POH)
and/or current Standard Operating Procedures (SOPs)


C-172S Procedure:

  1. Complete the Descent Flows/Checklists
  2. Talk to tower as appropriate for the airspace you're operating in
    • Controlled: "[Tower], [Callsign], [Location], [Information], [Intentions]"
    • Uncontrolled: "[Facility Name], [Callsign], [Location], [Intentions], [Facility Name]"
      • It is possible, but unlikely that a non-towered airport will have an information code, and if it did, there is no need to broadcast it
      • Requesting airport advisories will allow for other pilots or anyone monitoring the frequency to give updates on winds, the active runway, the number of people in the pattern, etc.
  3. Abide by tower's instructions, but plan to enter the traffic pattern at Traffic Pattern Altitude (TPA) on a 45° entry to the downwind, maintaining a one-half mile distance from the runway on the downwind leg
  4. Set power to 2200 RPM, to establish and maintain approach speed
    • Trim as necessary
  5. Abeam the point of intended landing, set power to 1500 RPM and set the flaps to 10°, begin a gentle descent and call
    • Controlled: "[Tower], [Callsign] abeam, gear 3 down and locked, [Landing Type]"
      • ATC: "[Callsign], [Winds], cleared for [Landing Type], [Runway]"
    • Uncontrolled: None
    • Anticipate the balloon effect when lowering the flaps
    • Trim as necessary
  6. At the 45° point to the intended touchdown point, commence a turn to the base leg
    • This is what you interpret to be 45° as you look over your shoulder back at the approach end of the runway
    • ICS: "Cleared left, forward, clear right, turning [Left/Right]"
    • Controlled: None
    • Uncontrolled: "[Facility Name], [Callsign], turning base for [Runway], [Facility Name]"
    • The wind is now at your side, so depending on its strength, you will need to compensate for drift with a crab angle
  7. Set the flaps to 20° and establish 75 KIAS
    • Anticipate the balloon effect when lowering the flaps
    • Trim as necessary
  8. Visually verify that the final approach is clear, and turn final
    • ICS: "Cleared left, forward right, turning [Left/Right]"
    • Controlled: None
    • Uncontrolled: "[Facility Name], [Callsign], turning final for [Runway], [Facility Name]"
    • Check your heading indicator against the runway heading to ensure you're lined up with the correct runway
  9. When landing is assured, set the flaps to 30° and establish 65 KIAS
    • Anticipate the balloon effect when lowering the flaps
    • Trim as necessary
  10. Transition from a crab to a slip
  11. By 300' above landing, complete a GUMP check
    • Gas: Fuel Selector and Pumps - SET
    • Undercarriage: Gear - DOWN AND LOCKED (if applicable)
    • Mixture: Mixture - FULL FORWARD
    • Prop: Prop - FULL FORWARD (if applicable)
  12. At the round out, commence reducing power to idle, continuing the flare to touchdown on the upwind main wheel first, holding the nose wheel off with back pressure throughout the roll-out; allow settling gently
    • Round out when the distant trees go out of sight (look long to flare)
  13. Once the aircraft touches down, it will tend to find centerline on its own; you need to be judicious with your inputs to avoid any induced oscillations
  14. Subsequent runway centerline tracking requires only small rudder inputs to initiate directional corrections
  15. Increase aileron deflection into the wind as you decelerate, due to less airflow decreasing aileron effectiveness
  16. Maintain directional control throughout the roll-out with the rudder, slowing sufficiently before turning on a taxiway
    • Remember to maintain taxi control inputs for winds
  17. Exit the runway without delay at the first available taxiway or on a taxiway as instructed by ATC
    • An aircraft is considered clear of the runway when all parts of the aircraft are past the runway edge and there are no restrictions to its continued movement beyond the runway holding position markings
  18. Proceed with taxi procedures

  • NOTES:
    • When performed correctly, your traffic pattern leg ground track will be straight as if flying in no wind conditions

Exiting the Runway After Landing:

  • Exit the runway without delay at the first available taxiway or on a taxiway as instructed by ATC
    • Pilots must not exit the landing runway onto another runway unless authorized by ATC
    • At airports with an operating control tower, pilots should not stop or reverse course on the runway without first obtaining ATC approval
    • Immediately change to ground control frequency when advised by the tower and obtain a taxi clearance
  • In the absence of ATC instructions, the pilot is expected to taxi clear of the landing runway by taxiing beyond the runway holding position markings associated with the landing runway, even if that requires the aircraft to protrude into or cross another taxiway or ramp area
    • The tower will issue the pilot instructions which will permit the aircraft to enter another taxiway, runway, or ramp area when required
  • Once all parts of the aircraft have crossed the runway holding position markings, change to ground control frequency when advised by the tower and obtain a taxi clearance
    • The tower will issue instructions required to resolve any potential conflictions with other ground traffic prior to advising the pilot to contact ground control
    • Ground control will issue taxi clearance to parking. That clearance does not authorize the aircraft to "enter" or "cross" any runways. Pilots not familiar with the taxi route should request specific taxi instructions from ATC

Common Errors:

  • Attempting to land in crosswinds that exceed the airplane's maximum demonstrated crosswind component
  • Inadequate compensation for wind drift on the turn from base leg to final approach, resulting in under or shooting
  • Flat or skidding turns from base leg to final approach as a result of overshooting/inadequate wind drift correction
  • Poor coordination during turn from base to final approach
  • Failure to complete the landing checklist in a timely manner
  • Un-stabilized approach
  • Inadequate compensation for wind drift on final approach
  • Failure to adequately compensate for flap extension
  • Poor trim technique on final approach
  • Failure to compensate for increased drag during side-slip, resulting in excessive sink rate and/or too low an airspeed
  • Attempting to maintain altitude or reach the runway using elevator alone
  • Focusing too close to the airplane resulting in too high a round out
  • Focusing too far from the airplane resulting in too low a round out
  • Touching down prior to attaining proper landing attitude
  • Failure to apply appropriate flight control inputs during roll-out
  • Failure to maintain directional control on roll-out
  • Touchdown while drifting
  • Excessive airspeed on touchdown
  • Excessive braking after touchdown
  • Slip:
    • Failure to reduce power to idle
    • Failure to add or increase flaps when available
    • Failure to apply and maintain full rudder deflection
    • Failure to use appropriate rudder/aileron combination during a crosswind situation
    • Failure to reduce pitch to maintain proper safe gliding airspeed
Figure 6: Airplane Flying Handbook, Crosswind Approach and Landing

Airman Certification Standards:

Conclusion:

  • Crosswind landing procedures are identical to that of a normal approach and landing, with the exception of wind corrections
  • Before every clearance to land, tower will give you the winds
    • Pay attention to this information! It may indicate a wind-shift you did not expect!
    • Set the heading bug, if available, to wind velocity to keep situational awareness to direction
  • Check with your Pilot Operating Handbook for the appropriate limitations for your aircraft
  • If flying an instrument approach into a crosswind and you subsequently break out, avoid the temptation to point at the runway if you already have a correction in for the crosswind, let it work and adjust as necessary

References: