Crosswind Limits

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boogs82
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Crosswind Limits

Post by boogs82 »

I went for a flight around CYLS today doing some circuit work. I was with an instructor because I had to check out of the rental aircraft anyway and I wanted to increase my checkout X-Wind from 5 knots that they check out at.

Well I had a crazy day. Winds were 330 @ 15-20 knots, although they seemed greater at times. I was looking at a 12-15 knots XWind on 28 and having a blast. I think this is the most XWind that I've had to work with and I had no trouble with it. For a bit I had max inputs to try and maintain centreline but I managed to keep the aircraft where it needed to be.

This might seem like no big deal to many people who have lots of hours, but it was a huge confidence builder for somebody with less than 100 hours (80.6 hours to be exact) to see that the airplane can still be controlled with high winds. It was even more fun because I had my daughter in the back. Now I have to get my six takeoffs/landings to bring her up alone.
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Re: Crosswind Limits

Post by JasonE »

I enjoy the challenge of a decent crosswind that is within my comfort level, makes things more interesting! I never used to feel that way, until I took on an 18G25 @ 70 degrees off the runway with an instructor. I learned what running out of rudder means! We touched down right in the middle and slid 50 feet sideways with a gust. Kept it straight the whole time, never looked back. It broke me. :rolleyes:

That was darn good practice (& needed) for my x-country solo. TAF's forcasted 26011KT, actual when I got to my 2nd last destination was 36016G26KT. You can see my airspeed bouncing from 80-100 mph in the video on approach. Ride 'em cowboy! Pretty sure you could see the sweat dripping down my neck too...

I've been told many times a PPL is a license to learn...Let's all keep learning!
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Re: Crosswind Limits

Post by PilotDAR »

My personal highs have been 37G43 at 30 degrees off the runway heading in my 150, and during flight testing for crosswind demonstration with a modification, 19G26 direct crosswind in a Grand Caravan. Those landings I did run out or rudder a few times, and had to use brake to keep it straight.

Remember that the wind speed number which is stated in a flight manual is not limiting, it is just required to be demonstrated during certification testing. The aircraft might well do more. If there is a "limit", that is either self imposed, or imposed by the owner of the aircraft.
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Re: Crosswind Limits

Post by Broken Slinky »

Definitely a good thing to practice. Never know when you'll have to put down on that single runway airport with an ugly crosswind.
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Re: Crosswind Limits

Post by HiFlyChick »

PilotDAR wrote:...Remember that the wind speed number which is stated in a flight manual is not limiting, it is just required to be demonstrated during certification testing. The aircraft might well do more. If there is a "limit", that is either self imposed, or imposed by the owner of the aircraft.
Actually, watch out on that one - some AFMs will actually say "Crosswind limit" (some, but not many), and in that case, it is indeed a legal limit. What you are talking about is when it says "Max demonstrated crosswind" - which is what the plane was demonstrated to be able to handle but does not limit going beyond that.
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Re: Crosswind Limits

Post by Rookie50 »

CZBA can be an issue when a low pressure system with strong winds appears. Typical southwest winds 200 -210 up to G 30. Rwys here are a nice long 14, considerably shorter 27 (@ 2000 usable x 50 wide with turbulance spilling of the escarpment.

Last winter landed on 27, wind was about 230 -240 G 33, not too bad an angle but very gusty. Horrible turbulance on final, (actually the whole circuit) from the escarpment, although under control. Went around twice to be assured getting it down early on the runway and without breaking anything. Took a couple of tries to learn where the shear was that day.

That was about limits I think for that runway. Fortunately no contamination, which can wreck your day. I have taken off on a (wide) slightly contaminated rwy in the winter X wind, that felt a bit uncomfortable.

Did seriously consider diverting to YHM that day.
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Re: Crosswind Limits

Post by HiFlyChick »

Now my husband and I have started a lively debate about crosswind limits in the AFM. I'm sure I've seen the word "limit" sometime and he thinks it's only been "max demonstrated". Anyway, if it says limit, it's a limit.

I've even been told by people that you can't take more than 10 kts on the tail when landing because that's all the book shows in the performance graphs. I disagree, because by that token you couldn't land on a wet, grass or sloped runway, because the perf graphs don't provide numbers for those either...
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Re: Crosswind Limits

Post by trey kule »

Actually, watch out on that one - some AFMs will actually say "Crosswind limit" (some, but not many), and in that case, it is indeed a legal limit. What you are talking about is when it says "Max demonstrated crosswind" - which is what the plane was demonstrated to be able to handle but does not limit going beyond that.
Well, to be as picky as you were, you might just want to review the full definition of what constitutes a max demonstrated crosswind.
It clears up how, and why pilots are able to exceed them routinely.

BTW. Pilot Dar makes his living dealing with these things. I am pretty certain he clearly understands the full definition for what a maximum demonstrated crisswind.
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Bolter
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Re: Crosswind Limits

Post by Bolter »

Isn't it just easier to make sure the Aircraft Carrier is pointed into the wind?
IAC I once touched down at max crosswind limit for the aircraft type only to discover that what was reported as a wet rwy was actually ice covered. Made for an interesting roll out as the aircraft weather cocked on touchdown and I spent 6000' using max control inputs and differential braking just to stay on the runway. Took ~8000' to get stopped, where the charts said I should have stopped in ~2500 (assuming it was wet)!
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Re: Crosswind Limits

Post by complexintentions »

Congrats boogs, it's always nice to hear about folks pushing themselves to their next comfort level and conquering it. I can assure you, building good habits and technique during training will stand you in very good stead down the road. An airplane is an airplane!

I've had a few interesting crosswind experiences over the years - I think in CYYT it's unusual to NOT land looking out a side window - but one day from my present employment iteration comes to mind. We were operating into CPH (Copenhagen) on a blustery fall day, B777-300ER, landing weight about 220 tons. Winds: 290/38kt. There are three runways: 04/22 L/R, and 12/30. Unfortunately RWY 12/30 was NOTAM'ed closed for construction work. Crap. But, still within the FCOM X-wind limit of 45 knots (dry runway), so off you go. The company has a x-wind limitation for FO's of 20 knots so, I guess it's my landing on 22L. Gee thanks! hahah!

Crosswind landing technique in an airliner is essentially the same as any aircraft, with a couple small differences. There are a couple of Boeing-approved variations, but essentially you still crab during the descent, and then de-crab in the flare with rudder and maintain wings level with aileron. Where it's a bit different is due to the distance between the pilot seats and the landing gear, which is 114 feet behind us. The localiser receiver antennas (antennae?) are mounted on the nose wheel gear doors. If you track the localiser, with a large crab, the landing gear will be pretty severely displaced left or right of the runway centreline. And you don't want to be correcting for centreline down low late in the approach in a large a/c. Not ideal. So one trick is to fly the localiser about half a dot left or right (depending on the wind) to keep the main gear centred over the extended centreline. Of course, if you're in visual conditions early enough you use that to aid in judgement.

The other weird thing that happens in such large crosswinds is the sight picture changes quite dramatically, again due to the length of the a/c. You maintain the crab until about 30 feet above the ground, which is when you start your flare. Since the mains are over the extended centreline, (or should be!) during the late stages of the approach you are basically hanging sideways looking down the runway edge lights or even the grass until you start to kick the nose straight again. It's a bit unnerving but we do get to practice in the sim. Good fun.

Anyway it all worked out that day, and it was amusing taxiing in watching other a/c hovering in sideways to land. Just thought I'd pass the anecdote along for the good folk who like to think airline flying is all pushing buttons and drinking cappuccinos. :mrgreen:
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Re: Crosswind Limits

Post by PilotDAR »

some AFMs will actually say "Crosswind limit" (some, but not many), and in that case, it is indeed a legal limit.
If an approved flight manual expresses something in "Section 2, Limitations" as a "limit" - it is. Other than that, a value expresses elsewhere in the flight manual, is not legally limiting. It might be darned fine advice, but you are not breaking a regulation if you exceed it. I expect that the required reference to demonstrated crosswind value is found in either Section 4, Normal Procedures, or Section 5, Performance, so as to be a part of the approved content of the flight manual, but not legally binding upon the pilot. Operating in excess of flight manual values might put the spotlight on the pilot in the case of an accident from an insurance point of view, but that might be mitigated with the reality that the pilot did the only thing they could do to land with the greatest safety possible.

In an approved flight manual, Section 2 presents all the limitations, which include all of the required placards. This is because the placards probably also present limitations to the pilot, so are repeated in the flight manual for out or aircraft reference, or if one has one has become unstuck (rendering the aircraft technically unairworthy :wink: ). Don't forget to also know the contents of any flight manual supplements, they could contain changed limitations, and you are bound to operate within them. I have seen flight manual supplements which did present a slightly different demonstrated crosswind value - though it was still not in Section 2, and thus not limiting.

Bear in mind that when you attempt a crosswind landing, you'll get a pretty good sense down final if you can succeed. Even as you flare, or after you touch, you can still apply power and go around, if you are not confident. I have surprised myself with what I could safely do when I tried in a crosswind. The "demonstrated crosswind" value is a calculated design requirement, not the actual limiting capability of the aircraft.

As for landing in tailwinds exceeding 10 knots in a slower GA airplane, I think attempting that, in anything other than a full emergency, is much more foolish than attempting a stronger crosswind. Most winds exceeding 10 knots are gusty, so a 10G15 wind on the tail is going to make a neat touchdown and rollout a misery in a slower GA plane.
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Re: Crosswind Limits

Post by LousyFisherman »

<Homer Voice>
Crosswinds, mmmmm
</Homer Voice>

The 20 hours spent doing crosswind landings just before my solo (wind was above the school limit for 10 days) were the most fun, and some of the most useful hours I wasted while getting my license. :smt040

However, I am still unable to crab and kick in the flare consistently despite the fact I do practise it. I usually start slipping relatively high and hold/adjust as needed.

LF
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Re: Crosswind Limits

Post by vanNostrum »

I remember the sweaty palms and shaky legs practicing X wind landings in the C 150 but for some reason I was allways more comfortable with the onewinglow approach than crabbing on final and I was OK in 90 degrees X winds 20 K or a little more but the limiting factor was that at 50 KIAS I would run out of rudder at around 10 degrees of bank and then start to drift.Never the less it was very good practice and a big confidence builder.
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Re: Crosswind Limits

Post by Redneck_pilot86 »

PilotDAR wrote:As for landing in tailwinds exceeding 10 knots in a slower GA airplane, I think attempting that, in anything other than a full emergency, is much more foolish than attempting a stronger crosswind. Most winds exceeding 10 knots are gusty, so a 10G15 wind on the tail is going to make a neat touchdown and rollout a misery in a slower GA plane.
There are scenarios where taking 10+ knots on the tail is acceptable (in my eyes, anyway) that are not full on emergencies. How about a long narrow strip that only has a turnaround at one end? Strips in the mountains that are too steep to land down hill? Obstacles on approach.

I regularly fly into about 20 different strips, some relatively flat and some pretty steep. Only 2 of those strips are useable in both directions in most scenarios, a few you can land downhill with a decent headwind. 7 of them are one way only landings, which means taking tailwinds on either approach or departure is mandatory.

I'm genuinely curious if there is any legal issues in taking 10 or more kts on the tail for either landing or departure. just about every company operating in this environment has had an over run incident at some point in the past, and I have never heard of any issues arising from tailwinds (legal issues, obviously crashing is an issue)
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Re: Crosswind Limits

Post by ahramin »

Redneck_pilot86 wrote:I'm genuinely curious if there is any legal issues in taking 10 or more kts on the tail for either landing or departure. just about every company operating in this environment has had an over run incident at some point in the past, and I have never heard of any issues arising from tailwinds (legal issues, obviously crashing is an issue)
There's nothing magical about 10 knots and you won't find it in the CARs. Many aircraft publish limitations and performance figures up to 15 knots tailwind.

For any airplane there is a point where control and performance become unmanageable. For many small aircraft the manufacturers have found 5 knots has been that point. For some pilots 10 knots is that point. You can certainly push it beyond that but at some point, one way strip or not, you're going from doable, to maybe doable. I'd quit long before I got to that point.
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Re: Crosswind Limits

Post by Redneck_pilot86 »

ahramin wrote:
Redneck_pilot86 wrote:I'm genuinely curious if there is any legal issues in taking 10 or more kts on the tail for either landing or departure. just about every company operating in this environment has had an over run incident at some point in the past, and I have never heard of any issues arising from tailwinds (legal issues, obviously crashing is an issue)
There's nothing magical about 10 knots and you won't find it in the CARs. Many aircraft publish limitations and performance figures up to 15 knots tailwind.

For any airplane there is a point where control and performance become unmanageable. For many small aircraft the manufacturers have found 5 knots has been that point. For some pilots 10 knots is that point. You can certainly push it beyond that but at some point, one way strip or not, you're going from doable, to maybe doable. I'd quit long before I got to that point.
Absolutely, I don't disagree. My question stems from my knowledge that most airplanes with a competent, current pilot are capable of doing things beyond what is published in the books. We've all heard the claim that taking any tailwind beyond what is published makes you a test pilot and your ass is not covered in the event of an incident. I chose 10 kts as the limit as that is what everyone else was talking about...really I meant whatever number is beyond published performance data.

I know for a fact on certain strips I can take 15 kts on the tail, on other strips I go home. I know this because I have been doing it for years, and many pilots ahead of me have been doing it. This exceeds the numbers published in the POH. While I realize that the published numbers are not a limitation, I am curious as to what litigation I may face in the event of an incident where I was operating outside of published data.
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Re: Crosswind Limits

Post by ahramin »

I've never heard of enforcement action for being outside published data, but a crash when operating outside published data could possibly put a pilot in a mess of litigation.
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Re: Crosswind Limits

Post by PilotDAR »

You could face enforcement action for breaking CARs, one of which states that though shalt not exceed limitations, as expressed in Section 2, Limitations, of flight manuals. However unwise, exceeding something stated in Section 5, Performance, is not a violation, unless that is also presented in Section 2.

That said, of the things I would never send a friend to do, would be landing a GA aircraft downwind in any significant wind. It doesn't mean it can't be done - it can, but the margins are much more tight. Very occasionally, on some rather obscure runways, it's got to be done.

Landing or taking off downwind will result in higher speeds on the surface. Drag increases as a square of the speed. The drag of the wheels, skis, floats is going to go up, and that is never good. The aircraft is going to be more twitchy, before it's ready to fly.

A gust from behind will really change the way the plane will fly, particularly in pitch. Pilots have been known to be behind in managing pitch while moving on the surface, doing it downwind adds an extra and significant element to that.
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Re: Crosswind Limits

Post by AuxBatOn »

Drag is based on airpseed, not groundspeed. The airspeed at whic you will takeoff will be the same. The groundspeed will be higher, leading to increased takeoff distance and lower margins if you need to abort the takeoff. In a multi-engine aircraft, the max abort sped will be decreased and the min take off speed on after an engine failure will be increased. If the min takeoff speed is greater than the max abort speed, you are in no man's land (can't take off or abort if you lose an engine between those speeds).

On landing, your groundspeed is greater, leading to increased stopping distances.

Unless I am scrambled and I have a departure end cable rigged (or my max abort speed is higher than my min go speed), I'll take the into wind runway any day.
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Re: Crosswind Limits

Post by photofly »

PilotDAR wrote:You could face enforcement action for breaking CARs, one of which states that though shalt not exceed limitations, as expressed in Section 2, Limitations, of flight manuals.
Where's that one buried?
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Re: Crosswind Limits

Post by PilotDAR »

Where's that one buried?
Not deep, if you're reading the CARs...
602.07 No person shall operate an aircraft unless it is operated in accordance with the operating limitations

(a) set out in the aircraft flight manual, where an aircraft flight manual is required by the applicable standards of airworthiness;

(b) set out in a document other than the aircraft flight manual, where use of that document is authorized pursuant to Part VII;

(c) indicated by markings or placards required pursuant to section 605.05; or

(d) prescribed by the competent authority of the state of registry of the aircraft.
It is the responsibility of the pilot to know what a "limitation" is for that aircraft. Just to make it more easy for the pilot to be sure, wording like this is becoming more common (this is from a flight manual supplement, but the intent is the same):
.....Compliance with Section 2, Limitations is mandatory.


Or similar wording...

Drag is based on airpseed, not groundspeed.
Drag resulting from the air is based upon airspeed. Drag resulting from contact with the surface is based upon groundspeed. During takeoff, there is a transition between them, based upon what's supporting the weight of the aircraft. The surface portion of the drag is a small factor for well inflated tires on pavement, but can get to be unmanagably great if the ground is soft, or on snow or water. The less groundspeed you have when you lift off, the less surface drag you will have had to overcome to get there. It is entirely possible for a takeoff to be impossible downwind because of the combination of surface drag and available distance, where into the wind, the combination would have worked fine. Some pilots who were unwilling to back taxi a lake have found this out the hard way.....

Downwind operations, beyond the value of the performance charts, put the pilot in untested territory, things can become more different there, more quickly - that's why it's untested!
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Re: Crosswind Limits

Post by AuxBatOn »

You mean friction then.
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Re: Crosswind Limits

Post by photofly »

As far as I know, nothing whose airworthiness was certified under CAR3 (contrasting FAR23) - which includes all the 1xx single engine Cessnas - is required by any standard to have an aircraft flight manual. Cessna, at its own discretion, provided guidance in a pilot operating handbook instead. I believe that means that 602.07(a) doesn't apply, and therefore even the limitations section of the POH for those aircraft is discretionary.

Cessna doesn't list the POH as "required for airworthiness" in the equipment list. In fact I don't think it lists it as "equipment" at all. (By contrast it does, however, list as required, a flight conditions limitations placard.)
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Re: Crosswind Limits

Post by JasonE »

Guess I'm good. My POH is too old to have a section 2. :) The performance charts are somewhat basic.

I'm sure my plane is more capable than I am.
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Re: Crosswind Limits

Post by HiFlyChick »

trey kule wrote:
Actually, watch out on that one - some AFMs will actually say "Crosswind limit" (some, but not many), and in that case, it is indeed a legal limit. What you are talking about is when it says "Max demonstrated crosswind" - which is what the plane was demonstrated to be able to handle but does not limit going beyond that.
Well, to be as picky as you were, you might just want to review the full definition of what constitutes a max demonstrated crosswind.
It clears up how, and why pilots are able to exceed them routinely.

BTW. Pilot Dar makes his living dealing with these things. I am pretty certain he clearly understands the full definition for what a maximum demonstrated crisswind.
Since I know nothing about Pilot Dar, or pretty much anyone else on this forum, I am making a statement based on the fact that his post sounded like he was saying that a statement about crosswind in the AFM (be it using the word limit or max demonstrated) was never a limit. You're right, I was being picky about the fact that if it says limit it's a limit, because TC tends to be picky. It's the old "should" vs. "shall" discussion when reading the CARs or AIM. I thought I had conveyed that the max demonstrated wasn't a limit, but I can't tell from your post whether you thought I said it was or not....

And BTW, I also make my living dealing with these things - so do any of us who fly for a living....
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