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Jet X-wind landings

Posted: Fri Apr 01, 2016 2:16 am
by Fendermandan
You have seen probably one of these videos


[youtube][/youtube]

I understand Dusseldorf can be quite windy, however there seems to be a quite slow reaction (struggle) on the rudder and aileron inputs on many crews.
How do you land/To in a commercial jet with the stiff x-wind? What are the handling differences vs the bug smashers?

Re: Jet X-wind landings

Posted: Fri Apr 01, 2016 2:52 am
by David MacRay
Dan!! What's new?

As shown the gear on those big jets can take it but it must be some ride when they do that.

Re: Jet X-wind landings

Posted: Fri Apr 01, 2016 3:08 am
by Liquid Charlie
Until you fly the heavy metal it's difficult to understand the video you posted. It seemed pretty standard to me and you can tell the auto land from the hand flyers. Several things come into play. Like spoilers added to the mix which can complicate things. The other is the amount of aircraft behind the pilot. For severe xwinds you can't line up on the centre line but at some point off the centre line which is going to put your main wheels on centre not just the nose wheel. There are several aircraft landing off centre line and you can see the corrections being applied. This was likely when the automatics were disconnected and the pilot lost the drift. With the "heavies" it was likely a complete autoland and landing crabbed. The new generation aircraft are better but the old 72 in a landing config 8 degrees wing down would get you a canoe scrape (wing tip) because of the amount of swept wing. On the 72 100 series the wing tips were as far back as the tail of the aircraft. Xwinds are completely different in heavy jets than prop aircraft right up to heavy turbines.

Re: Jet X-wind landings

Posted: Fri Apr 01, 2016 3:50 am
by Nark1
I'll try to add more tomorrow...
Like what Liquid Charlie said, length of the aircraft plays an important factor. You don't line up with the centerline.


Additionally the effing French decided that the Airbus stick should control the rate of roll, rather than aileron deflection. (I'll explain later).
So crosswinds are a bitch to get used to, until you master the crab, de-crabing and roll out.
Further the engine are easily scraped with too much roll during the flare, and "slope" technique.


One of my best landings I can remember was a hellacious X-wind in LGA (textbook upwind, downwind mains, the nose gear smoooooooth). I fought it all the way to the ground.
A commuting FA told the girls in the back it was her worst flight ever. Go figure.

Re: Jet X-wind landings

Posted: Fri Apr 01, 2016 12:18 pm
by Colonel
If someone is struggling to land a jet someplace,
don't even dream of trying it in your bugsmasher.

The faster you approach, the smaller the percentage
any given crosswind is.

The higher the wing loading (related to approach
speed), the easier the aircraft will be, to fly in the
turbulence that you experience.

I remember a gusty day a year or so ago, I had a
student up in the Maule.  He was all over the place,
working hard, trying to land tailwheel with that
strong, gusty crosswind.  It was quite something.

Then I jumped into the L39, and the landing was
a joke.  3 degrees crab (really) on final.

My father says his favorite instrument aircraft was
the F-104.  A 5 degree crab was a howling crosswind.
The wing loading was off the charts, so you got a nice
smooth ride in the bumps down low, even at 800 knots. 
Not so with the F-18.

As LC says, they are just so totally different.

Mike Mangold (now dead) that checked me out on
the hotrod L29, was disgusted with the aircraft
handling skills of his younger ex-USAF F-16 pilot
friends, that now fly 737's for Southwest.  Mike
flew F-4's - very different than an F-16, which
your grandmother could fly.

One of these FWS heroes blew a tire on an L39,
trying to land it with a crosswind.  Mike was not
impressed.

Re: Jet X-wind landings

Posted: Sat Apr 02, 2016 1:38 pm
by Eric Janson
[quote author=Fendermandan link=topic=2600.msg7681#msg7681 date=1459476985]I understand Dusseldorf can be quite windy, however there seems to be a quite slow reaction (struggle) on the rudder and aileron inputs on many crews.
How do you land/To in a commercial jet with the stiff x-wind? What are the handling differences vs the bug smashers?
[/quote]

Just to add some clarification:- None of the landings are autolands - the winds appear to be well outside autoland limits.

A characteristic of swept wing aircraft is the yaw-roll couple where using rudder will cause a wing drop. Too much bank will result in a pod/flap/flaptrack/wingtip strike depending on the aircraft type.

A lot of people don't use rudder except for take-off. A lot of people land crabbed - it's an approved technique. In the video only a few Pilots actually use rudder to align the aircraft with the runway axis.


Re: Jet X-wind landings

Posted: Sun Apr 03, 2016 3:26 am
by Fendermandan
Ahaaa moment, makes sense.


[quote author=Eric Janson link=topic=2600.msg7723#msg7723 date=1459604280]
[quote author=Fendermandan link=topic=2600.msg7681#msg7681 date=1459476985]I understand Dusseldorf can be quite windy, however there seems to be a quite slow reaction (struggle) on the rudder and aileron inputs on many crews.
How do you land/To in a commercial jet with the stiff x-wind? What are the handling differences vs the bug smashers?
[/quote]

Just to add some clarification:- None of the landings are autolands - the winds appear to be well outside autoland limits.

A characteristic of swept wing aircraft is the yaw-roll couple where using rudder will cause a wing drop. Too much bank will result in a pod/flap/flaptrack/wingtip strike depending on the aircraft type.

A lot of people don't use rudder except for take-off. A lot of people land crabbed - it's an approved technique. In the video only a few Pilots actually use rudder to align the aircraft with the runway axis.


[/quote]

Re: Jet X-wind landings

Posted: Sun Apr 03, 2016 3:37 am
by Fendermandan

I'm good, thank you buddy. Just busy as hell with the non airplane stuff.  O0  I haven't visited this e-hangout in a while, so just wanted to check-in.


[quote author=David MacRay link=topic=2600.msg7682#msg7682 date=1459479166]
Dan!! What's new?

As shown the gear on those big jets can take it but it must be some ride when they do that.
[/quote]

Re: Jet X-wind landings

Posted: Sun Apr 03, 2016 4:37 am
by David MacRay
Sounds good, hope it is a good "busy."

Re: Jet X-wind landings

Posted: Sun Apr 03, 2016 7:44 pm
by vanNostrum
[size=3]From Boeing's B 737 Flight Crew Training Manual [/size]



Crosswind Landing Techniques

Three methods of performing crosswind landings are presented. They are the de-crab technique (with removal of crab in flare), touchdown in a crab, and the sideslip technique. Whenever a crab is maintained during a crosswind approach, offset the flight deck on the upwind side of centerline so that the main gear touches down in the center of the runway.

[b]De-Crab During Flare[/b]

The objective of this technique is to maintain wings level throughout the approach, flare, and touchdown. On final approach, a crab angle is established with wings level to maintain the desired track. Just prior to touchdown while flaring the airplane, downwind rudder is applied to eliminate the crab and align the airplane with the runway centerline.

As rudder is applied, the upwind wing sweeps forward developing roll. Hold wings level with simultaneous application of aileron control into the wind. The touchdown is made with cross controls and both gear touching down simultaneously. Throughout the touchdown phase upwind aileron application is utilized to keep the wings level.

[b]Touchdown In Crab[/b]

The airplane can land using crab only (zero sideslip) up to the landing crosswind guideline speeds. (See the landing crosswind guidelines table, this chapter).

On dry runways, upon touchdown the airplane tracks toward the upwind edge of the runway while de-crabbing to align with the runway. Immediate upwind aileron is needed to ensure the wings remain level while rudder is needed to track the runway centerline. The greater the amount of crab at touchdown, the larger the lateral deviation from the point of touchdown. For this reason, touchdown in a crab only condition is not recommended when landing on a dry runway in strong crosswinds.

On very slippery runways, landing the airplane using crab only reduces drift toward the downwind side at touchdown, permits rapid operation of spoilers and autobrakes because all main gears touchdown simultaneously, and may reduce pilot workload since the airplane does not have to be de-crabbed before touchdown. However, proper rudder and upwind aileron must be applied after touchdown to ensure directional control is maintained.

[b]Sideslip (Wing Low)[/b]

The sideslip crosswind technique aligns the airplane with the extended runway centerline so that main gear touchdown occurs on the runway centerline.

The initial phase of the approach to landing is flown using the crab method to correct for drift. Prior to the flare the airplane centerline is aligned on or parallel to the runway centerline. Downwind rudder is used to align the longitudinal axis to the desired track as aileron is used to lower the wing into the wind to prevent drift. A steady sideslip is established with opposite rudder and low wing into the wind to hold the desired course.

Touchdown is accomplished with the upwind wheels touching just before the downwind wheels. Overcontrolling the roll axis must be avoided because overbanking could cause the engine nacelle or outboard wing flap to contact the runway. (See Ground Clearance Angles - Normal Landing charts, this chapter.)

Properly coordinated, this maneuver results in nearly fixed rudder and aileron control positions during the final phase of the approach, touchdown, and beginning of the landing roll. However, since turbulence is often associated with crosswinds, it is often difficult to maintain the cross control coordination through the final phase of the approach to touchdown.

If the crew elects to fly the sideslip to touchdown, it may be necessary to add a crab during strong crosswinds. (See the landing crosswind guidelines table, this chapter). Main gear touchdown is made with the upwind wing low and crab angle applied. As the upwind gear touches first, a slight increase in downwind rudder is applied to align the airplane with the runway centerline. At touchdown, increased application of upwind aileron should be applied to maintain wings level.