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I've seen several instructional videos on crosswind landing techniques. Some advise the pilot to crab the aircraft until just before touchdown when he/she should kick the rudder over to align the aircraft with the runway centerline. Others advise the pilot to slip the aircraft all the way down so that no other cross control maneuver is needed. Many of these videos also acknowledge the other way of doing things but say that their method is superior.

Is there an accepted "safer" method for flying a final approach with a crosswind or is it an entirely personal preference?

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  • $\begingroup$ Well so far the answers parallel the question, i.e., good descriptions of both techniques and justifications for each of them. I have always felt better crabbing on final until I read about some CFI's really emphasizing a stabilized approach and using that as a justification for slipping on final. $\endgroup$ – PJNoes Nov 5 '15 at 1:01
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    $\begingroup$ It can depend on the type of the aircraft. Aircraft with very long and low wings (e.g. most gliders) cannot land in a slip as they would hit the ground with the wingtips first. $\endgroup$ – vsz Nov 5 '15 at 7:20
  • $\begingroup$ Doesn't sliping reduce margins over stall ? It always seemed to me that it was more dangerous in the sense that if speeds falls to much, you risk a tailspin, and that is never good when the ground is close... $\endgroup$ – kebs Nov 5 '15 at 10:48
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    $\begingroup$ @kebs Slipping does reduce the stall margin (asymmetrically: the outer wing will stall first), but that's why we train for stall recognition. Re: spins, remember a slip is spin-resistant (the rudder is pushing the nose opposite the direction it would want to rotate) - the stall will be asymmetric and likely not as "pleasant" as one entered in coordinated flight, but a spin is less likely. (Skids on the other hand are spin-prone: The rudder is encouraging the nose to go in the direction it would want to rotate, so when you stall the spin develops quickly.) $\endgroup$ – voretaq7 Nov 5 '15 at 18:30
  • $\begingroup$ @voretaq7 Thanks for that clarification, I indeed mixed up skids and slips! $\endgroup$ – kebs Nov 6 '15 at 7:44
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Neither technique is "preferable" - the assumption that one is superior to the other is one of the most common false dichotomies (and over-simplifications) in aviation.

With some notable exceptions (like the Ercoupe which is incapable of a slip and lands crabbed) a proper crosswind landing should involve elements of both techniques.


Crabbing

Crabbing involves turning the nose into the wind so that some component of the aircraft's thrust is counteracting the crosswind, allowing the aircraft's ground track to align with the runway.

Advantages

Flying on final it is advantageous to crab into the wind: It is aerodynamically more favorable than a slip, and as the aircraft is kept coordinated it is more comfortable for passengers than a slip.
Pilots often find a crab subjectively "easier" to maintain for extended periods of time compared to a slip: It does not require the pilot to maintain "crossed controls", and it's similar to how we maintain our course in other phases of flight (you were probably crabbing into the wind on downwind just a few seconds ago, and on instrument approaches flying the localizer in a crab is analogous to tracking a VOR on the enroute portion of your flight).

Disadvantages

On touchdown however landing in a crab will put a side-load on the landing gear (the aircraft is traveling along the runway centerline, but the gear is not aligned with that direction of travel). In extreme cases this can damage the tires, cause difficulty controlling the aircraft, and possibly even damage the landing gear assembly itself.
"Kicking out the crab" to align the landing gear with the runway requires an abrupt control movement at low altitude (generally not a good thing), and if done too early the crosswind will begin to blow the aircraft across the runway (leading to a landing that's not on the centerline, a side-load on the gear, and in the worst case an unintended departure from the runway surface.


Slipping

Slipping involves banking the aircraft so that some portion of the wing's lift is counteracting the crosswind. Ordinarily the aircraft would tend to turn in the direction of the bank, so opposite rudder is applied to prevent the aircraft from turning and maintain the ground track parallel to the runway.

Advantages

Touching down on the runway a slip has the advantage of allowing you to align your landing gear with your direction of travel (down the runway) and avoid side-loading the gear. It also allows you to touch down on the upwind landing gear first which helps to stabilize the early roll-out, and positions your ailerons appropriately for taxiing with the crosswind.

Disadvantages

Slipping down final however is likely to make your passengers uncomfortable - the plane is slanted in one direction, the rudder is pushing the nose around in the other direction, and folks start to feel like their butt is sliding out of the seat.
Aside from passenger comfort a slip is a terribly inefficient aerodynamic arrangement (you're essentially trying to fly sideways), and not a "normal" way to fly in other phases of flight. You may have difficulty estimating the aircraft's performance and require power to maintain your glide path in this configuration.


Combining the techniques

So a crab is advantageous on final (and flying an instrument approach), and a slip is advantageous on touchdown. It logically follows that the two techniques can be combined to provide the advantages of both:

  • Crab down final (or on the localizer).
  • At some point transition into a slip.
    Exactly where you make this transition is pilot preference, but the transition should be smooth, simultaneously bringing the nose around to align with the runway while banking into the wind to counteract the crosswind component.
  • Touch down in the slip.
    Complete your rollout with the appropriate crosswind aileron deflection, controlling your ground track with the rudder as needed to prevent weathervaning.
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    $\begingroup$ Which one is preferred is on occasion part of the aircraft operating limitations. An example that comes to mind is that crews were trained to land the F-104 in a crab, no slip at all... Apparently it was safer to abuse the landing gear than to try to slip that particular airplane. $\endgroup$ – Brian Knoblauch Nov 5 '15 at 16:40
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    $\begingroup$ @BrianKnoblauch Aircraft limitations are something else that needs to be considered. As we discussed in chat another aircraft where a slip needs to be limited or avoided is the Tiger Moth as aggressive slips could cause the low-wing to scrape. $\endgroup$ – voretaq7 Nov 5 '15 at 17:33
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    $\begingroup$ In addition B-52 can crab all the way to landing $\endgroup$ – vasin1987 Nov 5 '15 at 18:14
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    $\begingroup$ On point 1, thrust is not counteracting the crosswind, but rather the aircraft's forward speed. If this were true, a glider could not compensate by crabbing. ;-) $\endgroup$ – Lnafziger Nov 5 '15 at 23:01
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    $\begingroup$ @BrianKnoblauch: Re the "apparently" on the F-104, that thing was notorious for its hostile stall behaviour. So, yeah... ;-) $\endgroup$ – DevSolar Nov 6 '15 at 8:46
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It seems airbus recommends a crab:

IV Final Approach Technique Figure 1 shows that depending on the recommendations published in the aircraftoperating manual, the final approach under crosswind conditions may be conducted:

  • With wings-level (i.e., applying a drift correction in order to track the runway centerline, this type of approach is called a crabbed approach [Airbus recommended technique]),

or

  • With a steady sideslip (i.e., with the aircraft fuselage aligned with the runway centerline, using a combination of into-wind aileron and opposite rudder to correct the drift).

Airframe manufacturers consider the following factors when recommending a wingslevel or a steady-side-slip approach:

  • Aircraft geometry (i.e., pitch attitude and bank angle limits for preventing tail strike, engine nacelle contact or wingtip contact)

  • Ailerons (roll) and rudder (yaw) authority

  • Crosswind component.

This Flight Operations Briefing Note focus on the wings-level / crabbed approach technique, recommended by Airbus, to discuss the associated flare and decrab techniques depending on the crosswind component.

From AirbusFlight Operations Briefing Note, Landing Techniques, Crosswind Landings pdf

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  • $\begingroup$ Airliners have to crab because if they use sideslip (i.e. wing down) the engines could touch the runway. Many airliners can touch down in a crab, i.e. no need to kick off the crab on some types e.g. B747 (an airline pilot may be able to expand on this). $\endgroup$ – Philip Johnson Nov 8 '15 at 10:06
  • $\begingroup$ @Philip Johnson - very true... a B747 documentary on the first flight testing of the B747 said the gear was approved for contact with the ground up to 45deg and they showed a test of it !!! $\endgroup$ – jwzumwalt May 28 '18 at 10:19
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    $\begingroup$ @jwzumwalt - 45 degrees is amazing for such a heavy aircraft. Try that in a cessna it wouldn't end well! $\endgroup$ – Philip Johnson Jun 1 '18 at 9:39
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    $\begingroup$ I saw a B747 land at the old Hong Kong airport hit pretty close to 45deg, bounce... then the pilot swung the nose straight, it was blown off center some what dangerously, he planted it again at a lesser angle, and there was smoke from rubber all over the place from each tire. There was so much smoke from rubber you could clearly see the tip vertices! $\endgroup$ – jwzumwalt Jun 1 '18 at 17:45
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I was taught the same way as Hmb. Although the larger Part 121 planes must touch down pretty level to avoid dragging an engine or a wing, they fly crabbed until short final. I was told that this is for passenger comfort as flying un-coordinated can make some squeamish pax a bit green. So for me, it is crab and kick - fly the approach crabbed and kick out the crab before you touch down.

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This comes down to situation and personal preference. I am more preferential to the crabbed approach as that is how I was taught and that is what I am comfortable with. If you are talking strictly from a safety point one could argue that what ever method you are more proficient and comfortable in is "safer". With a slipped approach you are coming in along the runway path so you will most likely not need much last second correction. A crabbed approach will require some adjustments close to touch down but like any landing you should be on full attention.

From a technical stand point, a slipped approach puts the plane in uncoordinated flight which can be viewed as inefficient. Slipping also increases drag that you will need to compensate for with power.

I also find that I prefer to crab in really gusty or high wind situations to keep the plane a bit more stable on final.

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I up voted Dave's answer, but mine is the same but opposite. I learned to slip all the way down final, and I prefer it, but I think it depends, like was mentioned in the other answer.

I like to slip because it aides in bleeding off speed, I don't have to upset the controls of the aircraft at the last minute, and I'm keeping the upwind wing down throughout the final, minimizing the chance of a gust lifting the wing up unexpectedly.

I think it depends on the aircraft, pilot, and situation, but I'm comfortable with the slip and that's what matters to me.

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  • $\begingroup$ You're comfortable with risking an engine strike? $\endgroup$ – Sean Mar 30 at 4:23
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To answer this

It depend on what are you flying.

From my side as an airbus pilot we are trained always to approach with a crab then at the flare we de crab and allign the nose with the runway centerline using rudder.

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    $\begingroup$ Hi Hmb, you could provide some good perspective if you expand on these points and give more background/explanation. $\endgroup$ – digitgopher Nov 5 '15 at 17:54
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I prefer crabbing down to round out and touch down, while I am crabbing I have all my controls in their neutral position with full control authority available, slipping requires deflection away from neutral which limits control action available while decending through possible shear or surface feature induced turbulence

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  • $\begingroup$ Welcome to Aviation Stack Exchange! You could make your answer better by providing sources to back up your claims. $\endgroup$ – dalearn Mar 29 at 20:58

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