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M20J Demonstrated Crosswind


Greg1

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The M20J POH shows a demonstrated crosswind of 11 knots. I know that's not considered a limitation. What is a the realistic crosswind capability?
One that you can handle ;) I know in my F, I am able to handle and feel comfortable is a 20 knot crosswind. Strongest I ever landed was in the 23 to 25 knot range (I angled the landing on the runway to take a few degrees out of the equation).
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Agree with Chris and Brian all depends on your piloting skills especially that day since we are all different from day to day.  I'v landed in 40+ winds with out problems and had problems in 10+ winds...

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You can land a plane in any wind, whether you can use it again without repair is a different matter!

 

One thing that I have found is to use only T/O flaps when landing in gusty winds...helps with control and avoids gust lift.

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What it comes down to is more what you are comfortable landing with not so much the capability of the aircraft.

 

Brian

 

Ultimately there is a practical aircraft limitation beyond our comfort levels. If the wind can cause you to drift across the runway while longitudinally aligned despite full aileron into the wind, you've pretty much reached the end of the aircraft's ability to land in it without breaking something.

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Ultimately there is a practical aircraft limitation beyond our comfort levels. If the wind can cause you to drift across the runway while longitudinally aligned despite full aileron into the wind, you've pretty much reached the end of the aircraft's ability to land in it without breaking something.

I'm not sure if the body length plays a role in this, but in my plane I run out of rudder authority before ailerons.

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Any time you go beyond the "demonstrated" crosswind, you are a test pilot.  The manufacturer, in effect, says, "it's up to you, Big Boy".

 

However, abiding by an 11 knot crosswind would certainly limit your flying.

 

Watching the various Youtube videos of Boeing crosswind demonstrations, makes me believe that the test pilots are merely trying get it on the ground without damage.  There are an interesting combinations of techniques, but I'm a believer that the Boeing landing gear structure is "very stout".

 

I personally (very personally) know a pilot that landed a B-757 15 knots in excess of the demonstrated crosswind limitations without incident and didn't get reprimanded.  However, he didn't receive any hero-pilot pay, either, so he wonders why he did it.

 

Operating outside the envelope, it's all on you.

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The demonstrated crosswind shown in the POH may be nothing more than a weather report. The number is derived one of four ways:

1. Achievement of the 0.2 Vso requirement of 23.233 (absolute minimum)
2. The greatest crosswind available.
3. The resources available for the testing.
4. The limit of the ability of the test pilot to safely land in a crosswind using normal skill and technique.

The number listed in the POH is not a limitation, but unless you're willing to go out and do some testing yourself, you're not going to know how the factory came up with the number. 

My guess it that, in the case of the Mooney, it's probably a weather report. Evidently it was blowing 11 knots on the day they got around to flying the certification flights pertaining to crosswind operations. In the real world, the maximum crosswind that you can fly a Mooney (or any airplane for that matter) is a function of rudder authority. As long as you have enough rudder authority to keep the nose lined up with the runway the crosswind is very flyable and safe. If you limit the amount of flaps during crosswind landings you are able to fly the approach at a higher speed and that in turn increases the airflow over the rudder making it mo
re effective which increases your crosswind capabilities. Now, if you're not sure of your abilities you'll need to work up to it carefully. Technique is important and things that aren't all that critical with 10 to 15 knot winds become critically important as the wind goes above 20 knots.Get with a CFI and go expand your personal envelope.

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My theory has always been that the max demonstrated crosswind component is a combination of marketing and safety. The manufacturer decides what components to test and, based on the test pilot recommendations, selects one. The test pilots are quite capable of exceeding it and probably have during testing.

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My theory has always been that the max demonstrated crosswind component is a combination of marketing and safety. The manufacturer decides what components to test and, based on the test pilot recommendations, selects one. The test pilots are quite capable of exceeding it and probably have during testing.

I keep hearing that "test pilots are quite capable of exceeding it and probably have during testing." That may be true, but when it comes to the data in your POH, Alan Average Private Pilot should have no problem achieving the performance numbers. Here's an interesting video which illustrates the way the FAA approaches test flying. Granted, a 747 is about as far away as you can get performance and size wise from any GA light airplane, but notice what they did to the airplane prior to the certification test flights...

 

http://www.boeing.com/Features/2011/..._05_04_11.html

Notice how they changed brakes prior to the test. Contrary to common belief, they don't use new brakes, etc. when these tests are run. It's max allowable takeoff weight and brakes, tires, etc that are at their service limits. Also, the crews "sit on their hands" so to speak for enough time to simulate the reaction time of the average pilot. They don't even use the thrust reversers. So much for the theory that only super human test pilots in brand new airplanes can achieve AFM/POH performance. Even I can do it if I fly the airplane by the book. However, all of that goes out the window if you start substituting your own pet procedures.

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I'm not sure if the body length plays a role in this, but in my plane I run out of rudder authority before ailerons.

 

I have never minded cross wind landings.  But I like long and wide runways for the extreme ones, however.  In my experience, it is important to keep my speed up (about +10 kts) to have greater control authority, especially the rudder...hence the comfort of a longer runway.  It also gives a little more gust insurance.  Takeoff flaps setting seems better than full flaps, as others suggest.

 

YMMV

 

-dan

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Consistency is probably the single most important element when it comes to getting good landings - crosswind or otherwise. Remember, regardless of what the winds are doing, you always use the ailerons, as much as necessary throughout the flare, to keep the airplane from drifting laterally - left or right - from over the runway centerline. If you've got a strong crosswind, it's simply going to take more aileron. If you've got little or no crosswind, it will take little or no aileron input. As far as rudder input goes, that's just as simple too - you add enough to keep the airplane aligned parallel to the runway. If you don't have much crosswind, it won't take much rudder. If you've got a lot of crosswind it will take a lot of rudder. If you've got so much crosswind that you hit the stops on the rudder and you're still not able to keep the airplane aligned you've reached the crosswind limit for that airplane. What I've just described is the "wing low" method for crosswind landings. Flying an airplane is dynamic. You're always moving the flight controls to make the airplane do exactly what you want it to do. (Remember: "FTDA" - Fly The D@mn Airplane) However, as your speed slows during the flare, you will need to increase control deflection to compensate for the loss of airflow over the control surface. It is not a "set it and forget it" scenario. (There is also a "crab and kickout" method, but unless you happen to be flying a jet transport with the engines mounted below the wings there's really not too much need to use that particular method. Although some guys like it, its use is in most cases purely personal preference.)

 

As far as gusts go, the usual technique is to add 1/2 of the gust value to your approach speed. You also need to look at the maximum gust value - you wouldn't want to be in the flare when the wind decided it was time to "gust to 25 knots" if you weren't comfortable with that strong of a crosswind. The biggest mistakes I see people make is that they fly the approach way too fast - they're using the Max Gross Weight approach speed when they significantly lighter, then they add 1/2 the gust factor plus a bit more for the wife and kids, then they add just a little bit more "just to be safe". Then instead of flying the approach at 1.3 VS + 1/2 the gust value, you'll see guys 5 to 15 knots too fast. And then they float and float and float... And of course the more time you spend floating down the runway, the more time there is to screw up the landing. 

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On my J I set a hard limit of 20kts for IFR at 1000ft ceilings, or 25kts for vfr. There are a lot of variables that may cause me to raise the numbers.

One being a 25kts direct cross wind really is hard on tires and maybe more importantly gear system. At 25kts it's necessary to land somewhat diagonally so in reality it's really not at 25kts cross wind.

At that type of wind I better have a darn good reason for landing at that airport because it's not a easy landing.

If I have passengers (wife counts as a passenger) I keep it closer to 15-17kts.

I once landed a pa28 in a 60 degrees right crosswind at night vfr, with it blowing 35kts gusting 48. Why? well it was in my single days and had "get-there-citus", you can put the rest of the story together.....regardless would I do it again, HELL NO. When operating that close to the edge anything that goes wrong will put you in a really bad situation. I was a bit younger, now I know it's more important to live to fight another day.

Besides I thought after landing I hit the right wing tip, but no impact marks...got lucky, not to repeat!

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I keep hearing that "test pilots are quite capable of exceeding it and probably have during testing." That may be true, but when it comes to the data in your POH, Alan Average Private Pilot should have no problem achieving the performance numbers. Here's an interesting video which illustrates the way the FAA approaches test flying. Granted, a 747 is about as far away as you can get performance and size wise from any GA light airplane, but notice what they did to the airplane prior to the certification test flights...

http://www.boeing.com/Features/2011/..._05_04_11.html

Notice how they changed brakes prior to the test. Contrary to common belief, they don't use new brakes, etc. when these tests are run. It's max allowable takeoff weight and brakes, tires, etc that are at their service limits. Also, the crews "sit on their hands" so to speak for enough time to simulate the reaction time of the average pilot. They don't even use the thrust reversers. So much for the theory that only super human test pilots in brand new airplanes can achieve AFM/POH performance. Even I can do it if I fly the airplane by the book. However, all of that goes out the window if you start substituting your own pet procedures.

I've landed the 747-400 simulator in 50 knots of direct crosswind. It was smooth winds and it as the maximum the sim would program for. Anyways, it was a little jerky but I landed it fine. You can't take all the crab out so when you touch down, the upwind wing will swing forward, and, since it's a 100 foot long swept wing, lift builds pretty fast and it takes a lot of aileron to hold it down. along with a great boot full of rudder to keep it straight.

As far a the 201, I've done 25 knots and that is also a little interesting. Key is getting the flaps up so you have some weight on the wheels and some more directional control. Of course this comes with a higher risk of grabbing hold of something you don't want (gear lever) so I usually avoid anything over 20-25 knots of crosswind

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I've landed the 747-400 simulator in 50 knots of direct crosswind. It was smooth winds and it as the maximum the sim would program for. Anyways, it was a little jerky but I landed it fine. You can't take all the crab out so when you touch down, the upwind wing will swing forward, and, since it's a 100 foot long swept wing, lift builds pretty fast and it takes a lot of aileron to hold it down. along with a great boot full of rudder to keep it straight.

As far a the 201, I've done 25 knots and that is also a little interesting. Key is getting the flaps up so you have some weight on the wheels and some more directional control. Of course this comes with a higher risk of grabbing hold of something you don't want (gear lever) so I usually avoid anything over 20-25 knots of crosswind

You got'a luv sims.  :)

 

My technique is to use minimum flaps to raise the 1.3 Vso a few knots. The extra speed also increases the rudder's effectiveness. (It also eliminates the need to screw around with getting the flaps up during the rollout.) As long as I've got any rudder left I'm golden. If I hit the rudder stops at any time on final, it's time to look for another runway.

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I have done 20 without too much difficulty. I have done 25, but was nearly out of rudder, ran diagonal to the runway, and it was hard on the gear and tires.

She definitely lands better the closer I am to gross. Solo and minimal fuel with a crosswind is interesting.

Also, it has been my experience that the winds in ground effect and touchdown are less than what I am seeing and feeling on final.

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I have done 20 without too much difficulty. I have done 25, but was nearly out of rudder, ran diagonal to the runway, and it was hard on the gear and tires.

She definitely lands better the closer I am to gross. Solo and minimal fuel with a crosswind is interesting.

Also, it has been my experience that the winds in ground effect and touchdown are less than what I am seeing and feeling on final.

You brought up a good point, the heavier the better when landing with cross winds.

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I just wrote a little on the 231 POH in the thread that is going on crosswind landings.  I bet if you look in Section IV, Normal Procedures, in the para. on Landing, you will see something to the effect that you should increase airspeed and use half flaps if the crosswind component is over your max. demonstrated.  You may also see that your "Normal" landing configuration as described in the manual is full flaps and something like 70 or 75 kts., mine is 75.  So if you put it all together, what the POH is telling you is that you land at full flaps and a low (70 or 75) airspeed in crosswinds up to max demonstrated.  Above that, reduce flaps and add airspeed.  I often land no flaps, especially in crosswinds or gusty winds.  Unless you are right at minimum landing speed, full flaps just produces too much lift and makes the aircraft prone to ballooning, and all it takes for that to happen is a gust at the wrong moment, which increases lift, or entering ground effect which does the same thing.  But to land in a stiff crosswind you need more than the normal rudder authority which you get by increasing airspeed, and to compensate for the increase in lift potential, you reduce flaps.  No flaps works perfectly fine in my aircraft and makes for much nicer landings except in calm wind conditions.

 

My stiffest crosswind was reported as 37 gusting to 54, 40 degrees from the runway, announced by tower when I was over the fence.  I hasten to add that I am not proud of it nor bragging, we were at the end of a 4:30 cross country and ran into unusual unforecast wind conditions caused by a strong cyclonic low advancing much more rapidly than forecast.  There might have been alternates with better runway angles, but conditions were changing so fast that there was no assurance the conditions at an alternate would not be as bad or worse when we got there.  I just figured out what I needed, among other things no flaps, and it worked.

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