Not All Crosswinds Are Equal

We all know that the maximum demonstrated crosswind value listed in airplane manuals is not a limitation. The crosswind speed listed is the strongest crosswind component test pilots successfully handled during developmental flying. Some pilot operating handbooks show demonstrated crosswind in the first section along with limiting airspeeds but Beech lists it in the “normal procedures” section along with other “airspeeds for safe operation.”

The maximum demonstrated crosswind for my airplane is 22 knots. I don’t know if I have encountered a crosswind component that strong, but in 5,000 hours of flying the same airplane I think I have come close. And 22 knots is a lot to stop sliding sideways.

Of course a crosswind is seldom 90 degrees to the runway heading. What we’re concerned about is the component of the wind that equals a 90 degree crosswind. So if the wind is blowing 30 knots I get concerned when its direction is more than 40 degrees left or right of the runway heading.

In the perfect world of airplane manuals and test flying the wind is steady. In our real world of flying the wind is often varying many degrees in direction and gusting many knots. If the wind were a steady 10 knots directly across the runway that would be pretty easy to handle. But if the wind is blowing 10 knots with gusts to 25 even though the direction is only 40 degrees left or right of centerline, that’s a different situation.

The crosswind capability of an airplane actually has two elements. One issue is flight control authority, and the other is capability to stay on the runway during rollout.

Identifying the crosswind limit in flight is really pretty easy. If you have the rudder or ailerons–or both–at the control stops and the airplane is still drifting sideways you have found the crosswind limit for what most of us consider to be an acceptable landing.

An airplane’s capability to handle a crosswind after touchdown is much more complicated. Among the many factors involved are the deck angle of the airplane on its landing gear, the traction available from the tires, the geometry of the landing gear wheelbase and track, and availability of lift killing devices.

It only takes a second to realize a taildragger lacks nearly all of the capabilities to defeat a crosswind during rollout. A taildragger is going to reach its crosswind limit at that critical point where the rudder is losing effectiveness, the tailwheel is not producing any traction, the downwind brake and tire are losing grip, and the wing’s angle of attack is increasing as the tail comes down.

The situation is the opposite with a tricycle landing gear. As the airplane slows more weight shifts from the wing to the wheels providing increased tire traction. The nose wheel gains more authority as weight shifts forward providing positive directional control. And the geometry of a trike landing gear causes the nose to swing away from the wind and straighten after touchdown, exactly opposite of a taildragger.

But in either type of airplane it is the crosswind gusts that can ruin your day. If a powerful gust strikes during the critical phase of touchdown and rollout you may find the crosswind capability of your airplane has been exceeded in an instant.

What can you do to increase your chances of not finding the true crosswind limit on a gusty day? In airplanes that lack effective ground spoilers–and that’s the case for most of us–I think the best approach is to not use full flaps. With only approach flaps, or no flaps down, the airplane has reduced ground effect and transfers the weight to the wheels more quickly. Most airplanes also float less without full flaps extended, and floating along with a gusty crosswind is a good way to wind up in the weeds.

The difference in stalling airspeed between flaps up and flaps down at a typical landing weight in my airplane is about 9 to 10 knots. The book doesn’t show stall speeds with only approach flaps extended so I add the full value difference between full flaps and no flaps stalling speed to approach speed when landing with only approach flaps. The increased airspeed on approach will require some added runway length, but if it’s windy enough to be concerned about landing and stopping the wind is lowering groundspeed and required runway anyway.

Somewhere along the way it became FAA dogma that was passed down by instructors that you should always use full flaps when landing. In large heavy airplanes, that makes sense. But for piston singles and twins it doesn’t always. On that gusty day I find there is more control available without full flaps. I can hit the touchdown target more predictably, and control on rollout is enhanced without the full flaps.

Be sure you have plenty of runway margin on a windy day and give the partial flap approach a try. Your airplane will still have a very real crosswind limit, but I bet you will find you have more control without the full flaps.

This entry was posted in Mac Clellan's Left Seat Blog. Bookmark the permalink.

18 Responses to Not All Crosswinds Are Equal

  1. Flying a straight tailed Bo, I much prefer full flaps once established on final. I’ve found no difference in control-ability be it partial or full flaps. Landing at the slower speed with power(all my landings are slow, with power. ) As with a short field landings, in gusty crosswinds as soon as the mains are planted, I let the nose gear down and get on the brakes, followed soon after with full up elevator. It’s a maneuver that requires lots of practice, but with that practice you can easily beat the book distance for short field landings. In a normal landing I use full flaps @ about 75 mph, (steep final with lots of power) and hold the nose gear off as long as possible. It produces a comfortable and quite short landings without the use of brakes.

    Demonstrated cross wind was 25. In the real world, much over 25 will have you skidding sideways. I’ve mentioned this before but, I had an abrupt change from a direct head wind (270) to a 90 deg cross wind (180) at close to rotation on a 95 deg day. (departing Oshkosh) It had to be well over 25 as we were skidding at a good rate. I crossed my fingers and pulled it off into ground effect. As soon as I realized we were flying, albeit only inches off the runway at a 45 deg crab, I started breathing again. I had expected it to cool down as soon as we were in the clouds. It wasn’t!

  2. JR A&P/IA, CFI says:

    Mac, I usually agree with you but not this time. I like full flaps on all landings with an immediate retraction upon landing. My theory is that the longer you float, the longer you are subject to the wind gusts. Also, after touchdown, put the aileron on the upwind side up to help hold that wing down (Turn into the wind).

    You are on the mark concerning tail wheel airplanes.

  3. Jeff Welch says:

    “It only takes a second to realize a taildragger lacks nearly all of the capabilities to defeat a crosswind during rollout.”

    WHAT!!!! This statement of yours is simply false.

    I flew Beech 18′s . I would hear pilots berate the aircraft and tell stories about the aircraft that were not true. The fact is they had no experience in the aircraft and only repeated false information they heard from others. Exactly what you are doing here.

    Today I teach in Scouts, Decathlons, Citabrias Huskys etc. I authored a taildragger book “Husky 101-Flying The Husky”. I have a second book coming out “Husky 101-Back To Basics”. As a CFI, I have not less than 10,000 landings in the back seat of taildraggers giving instruction in all kinds of cross wind conditions. I will take any of the above mentioned aircraft in a crosswind before a Cirrus, C172, PA28, etc.

    Proper training is everything. Don’t blame the airplane. Further, don’t make statements like the one above unless you have experience to back it up.

    • Mac says:

      Well, Jeff, even good old Beech disagreed because for the last years or production the Beech 18 had a nosewheel. And perhaps the best personal airplane of all time, the Bonanza, had the third wheel in the front. Beech figured it out.
      Mac Mc

  4. John Worsley says:

    My experience with a Cherokee 6 at a small (2700X35) airport in the mountains is that two notches of flaps works well on landing. Good control, and you don’t have the float when you hit ground effect that you do with full flaps.

  5. Wayne Cochrane says:

    I am intrigued by your comment:
    “Most airplanes also float less without full flaps extended…”
    I’d be grateful if you’d elaborate a little on why you believe this to be so. I’ve always had the belief that full flap increases drag proportionally more than it does lift. Do you perhaps consider that – even if you accept my belief as true in most modes of flight – that it does not apply in ground effect? If so, does the position of the wing (high, low or mid) or type of flap (simple, split, Fowler, etc.) have any role?
    Thank you for a great series of thought provoking columns.

    • Mac says:

      Hi Wayne,
      I think flaps increase lift in ground effect and that’s why I have observed more float in many airplanes. A low wing airplane has stronger ground effect because the wing is closer to the runway so expect a difference there compared to a high wing. Also, with less than full flaps the wing is going to give up flying at a higher airspeed and you will land.
      Mac Mc

      • Wayne Cochrane says:

        Thank you – I found this column (and your reply) especially interesting, and surprising.

  6. Pingback: Crosswind Prep | High Altitude Flying Club

  7. Larry N. says:

    I have to agree with Jeff W. about tailwheels and crosswinds. Though I’ve never flown a Twin Beech, I have lots of time teaching and flying in everything from Cubs and C-150s to C-180, Bonanza, Stearman, and more.

    For the actual landing in a gusty crosswind, I’ll take something like a C-180 every time, though it gets touchy as you get slow, but I’ve landed and stopped facing the wind in Champs and such when I needed a wing walker to taxi, and I’ve done a lot more in the C-180 with Cleveland brakes (I’d not try it with the Goodyears) without the need for a wing walker. I’d actually, in certain situations, prefer the C-180 to a Bonanza or Baron (or other nosedragger), though it takes a lot of care to taxi it after landing — more than a Bonanza, but doable.

    As a flat statement, I feel you’re wrong. For most people with only moderate experience in tailwheels, especially in the lighter ones, your statement comes close to the mark.

    “And perhaps the best personal airplane of all time, the Bonanza, had the third wheel in the front. Beech figured it out.”

    What Beech figured out was marketing, and pilots who weren’t as proficient in rough situations as a few were, not whether nose or tail mounting the third wheel made it handle crosswinds better — it’s just easier to handle on the ground, for the most part, which doesn’t make it more capable, just easier.

    • Ron Rapp says:

      Well said. The land-o-matics have their place, but so do tailwheel aircraft. What Beech (and Cessna, and Piper) did was for marketing’s sake. My experience has been that landing a tailwheel airplane will be easier in a crosswind, but taxiing one can be a challenge if the wind is high.

      • Joby Wieser says:

        your comment confuses me. I am a new Pilot so maybe I’m missing something but I thought that in the air a plane will fly exactly the same weather it has a nose or tail wheel, if that’s the case shouldn’t landing be the same to the point of stalling and touching the ground? Once on the ground isn’t a tail wheel more difficult to control?

  8. Dan Brown says:

    Your comment on the critical point of the landing rollout for tailwheel aircraft would seem to apply to a wheel rather than 3-point landing — which is why I prefer a full stall landing in crosswinds.

    My experience (most single engine Cessna, Piper and Beech ships) is that the increased control authority that comes with the higher speeds of a flapless landing when the wind is gusty more than compensates for the quicker flare with full flaps.

    My current aircraft is a 1940 Taylorcraft – light wing loading and poor mechanical brakes make for difficult taxiing in strong winds — especially trying to turn downwind.

  9. Scott Spencer says:

    A taildragger with good brakes can be wheel landed in high crosswind components. All lift is dumped at touchdown by keeping the tail high and going zero (or slightly negative) alpha. The tail stays high in clean air (not in turbulent air from fuselage and wing as in 3 point) and has good rudder effectiveness, and the ailerons remain effective to very low speeds because the wing can be kept flying (unstalled) to well below normal stall speeds due to no load on wings.

    The true crux of the method is effective steering from differential braking -which is very effective due to all aircraft weight (and possibly even more load due to ‘negative’ lift) being placed on the wheels.

    Finesse in braking is the key while keeping a balance on the mains against braking deceleration by using the elevator (the elevator also still ‘flying’ and effective). As the plane decelerates keep both main wheels firmly on the ground (using the zero alpha and effective ailerons to accentuate braking ) -especially on the critical downwind wheel. As the plane stops let the tail down and plant the tail wheel.

    The phrase ‘keep FLYING the plane all the way until it stops’ goes to its full and true meaning here.

    None of this is possible in a three point attitude. In a three point you soon are ‘just along for the ride’ in a strong crosswind, as during the rollout the effectiveness of all the flight controls goes away due to a stalled attitude and/or dirty air over the rudder (riding in turbulent flow from wings/fuselage). Add to this the poor braking authority as the wings are still doing a little lifting due to the nose high attitude.

    Wheel landings in crosswinds allow for taildraggers (with good brakes and capable pilots) to handle much more crosswind component than is possible in a three point attitude -and the physics of the matter support this argument wholly.

  10. Larry N. says:

    Well said, Scott. Braking is a major part of handling strong crosswinds. I agree that wheel landings are the way to go, provided you have very effective brakes (such as the Clevelands on the C-180 I towed gliders with). With weak brakes, such as the original Cub, it depends a lot on the specific conditions, but in any case you can’t handle crosswinds as well as with good brakes.

  11. Frank Giger says:

    I’m happy to see Mac write about gusty winds and tail draggers!

    I’ll second his comments on using either partial or no flaps in crosswinds, particularly in light aircraft. In the FlightDesign CTLS, for example, keeping the flaps up in a strong or gusty crosswind is much more effective, owing to somewhat squirrelly nature it seems to have due to the large rudder. She’ll taxi nicely, though!

    In a Champ it’s a matter of actively flying the aircraft until tie down or pulling the hangar door, with a mind that on a paved runway the painted lines are suggestions – unless on is on a check ride there’s nothing that says one can’t land/taxi diagonally on the pavement. Or that one can’t taxi at a snail’s pace. Or put it in the grass pointing into the wind and holler for help… might get some smiles and good natured gibes later on, but no aviator worth his salt will fault a guy for knowing when he’s over his (and his aircraft’s) head and puts safety ahead of ego.

    I will take exception to the notion of using brakes during landing in light tailwheels like Champs – it’s disaster in the making, IMHO, especially with heel brakes. One is doing two things at once, managing the brake and the rudder using the foot the wrong way. One can’t really push the rudder without pushing the brake, even with the ball of one’s foot (which one should be using anyway), or conversely apply brake while pushing the rudder. The mechanics of our bodies don’t really allow for it.

    I’ve done both wheel and three pointers in gusting or big crosswinds. I set up for a three pointer with a little extra power and see how it turns out, allowing myself options either way. Firmly determining which type of landing to do in challenging conditions ahead of time isn’t really thinking at all! Plus there’s always the go-around….

  12. Thanks on your marvelous posting! I truly enjoyed reaing it,
    you are a great author. I will make sure to bookmark your blog and
    may come back sometime soon. I want tto encourage one to continue your great
    posts, have a nice afternoon!

    My blog – boxes of fruit delivered

  13. info says:

    This paragraph is in fact a good one it helps new web people, who are wishing for blogging.|

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>