Sideslip or De-crab in the flare

What technique do you use for landing in a crosswind?

  • Sideslip

    Votes: 12 16.0%

  • De-crab in the flare

    Votes: 63 84.0%

  • Slam it on while still crabbed

    Votes: 0 0.0%
  • Total voters
    75
I personally like the de-crab, but my preferences are not really germaine to this. Interesting, just went and looked up the Boeing recommendation and it does align with what you wrote. I think that the side-slip does provide enough side velocity to compensate for the crosswind up to the recommended max, but the gust factor is what they appear to be worried about.
 
It's interesting how much technique has to change depending on equipment. Using anything but a sideslip in a Citabria will put you on a world of hurt, and while a Skyhawk may tolerate some crab or decrab, it was considered terrible technique at my flight school. The crab or decrab methods seem like compromises to deal with the wingtip/nacelle scraping issues. I know a Boeing is certified to land in a full crab, but it must be hard on the airplane, and any real crosswind using a decrab technique will result in the airplane ending up downwind of centerline. I've always used a sideslip in the 145 just like a Skyhawk, but the AOM gives no warnings concerning the wingtips (just a max demonstrated of 30kts). I guess you must just adapt to your equipment.
 
J Cole said:
It's interesting how much technique has to change depending on equipment. Using anything but a sideslip in a Citabria will put you on a world of hurt, and while a Skyhawk may tolerate some crab or decrab, it was considered terrible technique at my flight school. The crab or decrab methods seem like compromises to deal with the wingtip/nacelle scraping issues. I know a Boeing is certified to land in a full crab, but it must be hard on the airplane, and any real crosswind using a decrab technique will result in the airplane ending up downwind of centerline. I've always used a sideslip in the 145 just like a Skyhawk, but the AOM gives no warnings concerning the wingtips (just a max demonstrated of 30kts). I guess you must just adapt to your equipment.
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What you say is mostly true. If I flew a GA airplane I'd still likely use sideslip when landing in a crosswind. That's the technique I used up until flying widebody jets.

The bolded part however is not correct. A proper de-crab technique done just prior to touchdown will not result in much, if any, movement off of the centerline. If it is done too high, then yes, drift will ensue.

The key, I think, that a lot of pilots miss is that "just prior to touchdown". I takes quite a bit of practice in the simulator to start to nail the timing right. Next time you, or anyone who is reading this, is in the sim and the instructor asks if there is anything you would like to try then give this a try. Start with lighter crosswinds and then gradually increase them.

Honestly, it took me about two-three years to be converted, but now I wouldn't even think about trying to slip a large jet in a crosswind.



Typhoonpilot
 
typhoonpilot said:
I think what you are referring to is the De-Crab in the flare method, at least in a jet. There is no way you can transition from crab to a full sideslip condition below 50 feet in a jet airliner. At least not without serious risk of striking a wingtip, engine nacelle, or trailing edge of the flaps on the runway.


Typhoonpilot
Click to expand...

I did it for 13 years in jets with no ill effects. Most guys I flew with did the same.
 
typhoonpilot said:
What you say is mostly true. If I flew a GA airplane I'd still likely use sideslip when landing in a crosswind. That's the technique I used up until flying widebody jets.

The bolded part however is not correct. A proper de-crab technique done just prior to touchdown will not result in much, if any, movement off of the centerline. If it is done too high, then yes, drift will ensue.

The key, I think, that a lot of pilots miss is that "just prior to touchdown". I takes quite a bit of practice in the simulator to start to nail the timing right. Next time you, or anyone who is reading this, is in the sim and the instructor asks if there is anything you would like to try then give this a try. Start with lighter crosswinds and then gradually increase them.

Honestly, it took me about two-three years to be converted, but now I wouldn't even think about trying to slip a large jet in a crosswind.



Typhoonpilot
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Interesting. It sounds like the decrab is a very refined technique. Even if you didn't do it perfectly I suppose it would be better than scraping a nacelle.
 
Lear 35, 45, and now Falcon 900 here and I was taught and use the de-crab in the flare method. In the King Air and other light straight wing airplanes that I have flown I just flew in a crab to the runway and then zero out the crab and side slip for drift correction.
 
typhoonpilot said:
What you say is mostly true. If I flew a GA airplane I'd still likely use sideslip when landing in a crosswind. That's the technique I used up until flying widebody jets.

The bolded part however is not correct. A proper de-crab technique done just prior to touchdown will not result in much, if any, movement off of the centerline. If it is done too high, then yes, drift will ensue.

The key, I think, that a lot of pilots miss is that "just prior to touchdown". I takes quite a bit of practice in the simulator to start to nail the timing right. Next time you, or anyone who is reading this, is in the sim and the instructor asks if there is anything you would like to try then give this a try. Start with lighter crosswinds and then gradually increase them.

Honestly, it took me about two-three years to be converted, but now I wouldn't even think about trying to slip a large jet in a crosswind.



Typhoonpilot
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Which is interesting as the autoland sets up a slip, and the height at which it begins is based on the crosswind component.
 
In smaller jets I used a sideslip but in both the 747 and 777 I de-crab in the flare. The autoland in both airplanes introduces a sideslip but in the 747 (especially the -8) you had a real danger of a pod strike on 2 or 3 in a sideslip. The 777 really doesn't like landing on one set of wheels first (maybe can get away with it on the -200) so the de-crab method allows both sets of mains to touch down at the same time. Some think it is just a stomp on the rudder and forget aileron though which are the ones that we just tell to land in the crab :)
 
ATN_Pilot said:
I did it for 13 years in jets with no ill effects. Most guys I flew with did the same.
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I agree, I did too and for longer than you. I have over 5000 hours in the DC-9 series and used the sideslip technique the whole time, but as the jets get a little bigger and the wings longer the margin of safety is reduced when you are banked like that close to the ground. In the 787 and the upcoming 777X it's a real issue. As RJ said, in the 747 it is a big issue with pod strikes.


TP
 
typhoonpilot said:
I agree, I did too and for longer than you. I have over 5000 hours in the DC-9 series and used the sideslip technique the whole time, but as the jets get a little bigger and the wings longer the margin of safety is reduced when you are banked like that close to the ground. In the 787 and the upcoming 777X it's a real issue. As RJ said, in the 747 it is a big issue with pod strikes.


TP
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I can see that. Your previous post said all jets, though.
 
Touchdown bank angle is important in the 747, but in the time I flew it in real world conditions (including nasty gusty days), it isn't near the issue you are choosing to make it.
 
TwoTwoLeft said:
Landing in a crab... There may be a few exceptions for contaminated runway surfaces. Generally, unless your airplane is an Ercoupe, equipped with crosswind landing gear, trailing links for the mains or structurally approved, landing crabbed is a really bad idea in anything from a J3 cub to a jet. Its hard on everything from tires to structure and it just looks like amateur hour. You'll eventually need to apply proper control inputs on the roll out, so why not just apply them correctly in the flare?
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F-117. 67.5 degree permanent sweep. No slats, no flaps. Pretty much what kept us flying Category E instrument approach mins. You try the winglow method, you'll induce a huge descent rate or else possibly interrupt the clean airflow to the crab-direction wing via the fuselage

For both it and the T-38 (which had little wing area), our crosswind landings had to be done with a crab all the way to touchdown. There was no such thing as the wing-low method, lest you want to stall the jet being cross controlled. Just as for the F-117, there was no such thing as aerodynamic braking on rollout.....very strictly prohibited.
 
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typhoonpilot said:
I think what you are referring to is the De-Crab in the flare method, at least in a jet. There is no way you can transition from crab to a full sideslip condition below 50 feet in a jet airliner. At least not without serious risk of striking a wingtip, engine nacelle, or trailing edge of the flaps on the runway.


Typhoonpilot
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From what i'd gathered from my bretheren, the KC-135As and Es had something like a max 7 or 8 degrees roll limit on landing touchdown. But when the KC-135Rs came out, with the CFM-56s replacing the J57s/TF33s, tht reduced to something like 3 or 4 degrees on touchdown, else you drag an inboard nacelle on the runway.
 
MikeD said:
F-117. 67.5 degree permanent sweep. No slats, no flaps. Pretty much what kept us flying Category E instrument approach mins. You try the winglow method, you'll induce a huge descent rate or else possibly interrupt the clean airflow to the crab-direction wing via the fuselage

For both it and the T-38 (which had little wing area), our crosswind landings had to be done with a crab all the way to touchdown. There was no such thing as the wing-low method, lest you want to stall the jet being cross controlled. Just as for the F-117, there was no such thing as aerodynamic braking on rollout.....very strictly prohibited.
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You wouldn't even try a little rudder at the last second?
 
Sometimes the original 737-200's with the 'castering' main gear is genius.

Strangest sensation during takeoff with a heavy crosswind.
 
Derg said:
Sometimes the original 737-200's with the 'castering' main gear is genius.

Strangest sensation during takeoff with a heavy crosswind.
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I think they caster on through at least the -400.

It was always strange taxiing behind them watching them go sideways. Also cool to see the engine glow at night at the -300s.
 
Here's how it's done by the pros. BTW, the landing gear can be offset by +/- 20 degrees. During approach the offset is calculated and dialed-in.

 
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