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WINDY!! What are your limitations?

cawmd82

cawmd82

Well Known Member
The last couple of weeks In the DFW area have seen all kinds of high and gusty winds including some relatively odd angles. Things here are usually pretty much NW-SE, one or the other. Today at one point ADS had 270/22 g30.

To the point....What are some of your personal comfort levels on winds for take offs and landings, with an emphasis on crosswinds?

Before the flames....Obviously one's experience will determine what is safe for that individual only--I am looking to get some dialogue on what various people find acceptable for themselves.
 
Determined by the doors

I am fortunate to be based at an airport with several runways. Seriously, the determining factor as to whether a flight is possible is the hangar doors. Part of the door folds then the remainder slides. That folding part is treacherous. It can grab you and overpower you and sling you.

If it wasn't for the doors, crosswind component would probably be a factor, although I find the RV-6 to be very competent in that department.
 
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90 deg cross wind 25kts is easy ... but i did make it with a 35 kts 90 deg cross wind, I told my passenger i was going to make one approach, if we had to go missed i had alt airport with the wind right down the runway.
 
Winds

We have also been having unusually high winds for this time of year here in St Louis. Just had the conversations with some of the locals here at the airport that the direction seems to be at strange quartering direction. We have a main paved runway 16-34 (with a non-official grass strip along the west side) and a grass runway 7-25. Winds seem to be very high this winter typically between 220 and 290 deg. at around 15 kts gusting to 25 (some time 35). Also low level wind sheer of 40-50 kts at typically 45-90 different then on the surface at just about pattern altitude.

With my 6A I only use the main runway (especially now with the soft field of a sloppy STL winter) and I am constanly trying to make the call of my comfort level of cross winds. I started out last year very shy of crosswinds in the RV. I think that was mainly due to my many hours of Cessna 140 tailwheel time and low time on the RV. The 140 I would use the grass runways and therefore less crosswinds no mater what direction of the wind. Now that I have become comfortable with the amount of control power the RV has over anything else I have flow, I have been flying with crosswind components up to 20 kts. That is my current comfort zone after 180 RV hours.

This subject maybe related to the taildragger vs nosedragger and the flipping over of the A-model debate. I would be able to fly at higher crosswinds (to the paved runway) if I had a taildragger because I would use the grass cross runway. Go figure.
 
Gust Factor

It surprises even me that for someone as procedural and "flight rule" oriented as I am, I don't have a hard and fast wind limit. I know it when I see it (if the airport cat blows by about 3 feet off the ground, it's too windy....)

Seriously, I am mostly worried about the gust factor - steady winds don't really bother me, but a gust factor of ten knots or more really makes me think - that's a huge percentage of our stall sped, and things can get really exciting. Directional "gusts" are also something that get my attention - swings of 30 degrees each side of steady state can make me decide to stay on the ground if the winds are up near 20 knots (Or really tighten my harness if I arrive at a destination and find them that way).

When I started flying the RV, I paid a lot of attention to the wind forecast, and decided not to fly on more than a few days. AS I got more comfortable with the plane, I really reached the point where I pretty much ignore destination wind forecasts unless I see numbers in the 20's, in which case I study them more carefully.

This is all really going to depend on personal comfort and familiarity with the airplane. I thought about doign a true handling qualities flight test program on this at one time, but decided to just go flyin ginstead...;) Perhaps Kevin H can give us some Cooper-Harper ratings when he's flying!

Paul
 
After close to 180hrs I am fairly comfortable with 15kts direct, I have landed in 25kts direct, but it was not what I would chose to do. Honestly if its not a direct cross wind I will go if its under 25kts with the gusts.
 
I too can't describe any hard numbers - there are way too many variables. Terrain, including locations of buildings on or near the airport are a big factor.

I will tolerate going into a cross-windy airport more when I know that there are options nearby for other runways. This allows an approach with the idea of not in any way needing to land.

I have found that, I think due to the small distance above the ground that the RV's wings are, crosswind correction really diminishes the last few feet.

I agree with Paul on the gusty factor - use a lot of caution.

Runway conditions make a huge difference - any ice and the limit is way down. Full cross controls on the rollout or initial take off run may not prevent drift...

Another factor is left or right xwind. On take off, we can tolerate a fair bit more from the right, so that needs to be considered. If one needs to abort a landing after touchdown, the same thing applies.

In general, having a 15 knots crosswind component will lower the upwind wing an surprising amount. If I needed to pick a number, it would be 15 knots xwind component.
 
We fly a light sport, and our limits are low compared to RVs and certified airplanes. The airplane is fairly easy to land up to 10G13. Above that, you need to be very active on the controls.

The limit depends on whether we're solo or with a pax - the airplane lands much better at 1300lb than 1100 (15% more weight). Solo, I'm fine up to 12kt with 5 kt gusts. Dual, 15 kt with 5kt gusts. Crosswinds need to be limited to about 7G10. If we're going XC and the winds are higher than expected at the landing airport, we'll try and landing (go-arounds are pretty easy), but we won't go if forecasts are above the limits.

Takeoffs are rarely an issue with LSA - the light weight and high horsepower of the Rotax (most LSA use it) make takeoffs short, even at MGTW. However, directional control can be more challenging with the steerable nosewheel - toe brakes are easier once you get used to them.

This is actually one of the problems with LSA - the light weight allows them to be efficient with power and have low stall speeds, but it makes them more vulnerable to winds on landing. We're more comfortable with moderate winds now versus where we were six months ago, but it's taking time.

TODR
 
I agree on the gust factor, too. Steady winds up to 20 knots are fine for me. I have landed several times at over 30 knots somewhere between 70 and 90 degrees. Not my favorite flying, but my 7A handles it well. If it's gusty, I just stay on the ground if the gusts exceed 15 knots, unless I'm traveling and my destination is predicting better winds.

Roberta
 
One thing to keep in mind when reading about crosswind landing adventures is that the airport wind conditions at the time are not necessarily the conditions your are actually exposed to on touchdown when landing. At my airport, there's not much of a crosswind component once down to the runway regardless of wind speed. If I knew I had to land in an unsheltered 35KT crosswind, I wouldn't bother making a crosswind landing, I'd probably just land directly into the wind on a taxiway...touchdown ground speed would be about 10 mph!

To get a feel for truly how much crosswind you and your airplane can handle, go to an airport with wind reporting that is wide open with absolutely no obstructions from the prevailing wind direction. Make a normal approach and practice flying down the runway centerline a couple feet off while holding heading and track. No need to touchdown. 15KT of 90 degree unsheltered crosswind is all I really care for in my RV-3. At normal landing speeds, it's close to running out of rudder at this point. Of course, the faster you are the less correction you need, but I don't care to land at 100 mph.

That being said, I worry a lot more about wind shear, gusts, and mechanical turbulence than pure steady crosswind. This is more likely anyway when the wind really starts kicking. Anyone who has encountered a scary sinker down low surely appreciates the high power-to-weight ratio of an RV.
 
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xwind

I'm with everyone else here, it's the gusts that concern me, not a steady crosswind. I have only landed like this 2 times in my flying career but don't forget the option of touching down on the runway and rolling out onto the taxi way in a high 90 degree cross wind. The first choice should alway be an alternate runway or airport but in case that option is not available the pilot is responsible for getting the A/C on the ground safely. And yes, one of those landings I was asked to stop in and talk to the controller. He was very understanding but asked that in the future I inform the tower of my intention to touch down on the base leg. :D
 
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sandifer said:
One thing to keep in mind when reading about crosswind landing adventures is that the airport wind conditions at the time are not necessarily the conditions your are actually exposed to on touchdown when landing.
Click to expand...
Well said. I remember one such day at Hays, KS - I left the ASOS going on the standby monitor of the SL40 while in the pattern. The wind would shift and gust frequently and was about 30 deg different than when I first called up.

TODR
 
Crab angles

For 90 degree crosswinds of magnitude (at the aircraft) as shown, the crab angle through the air, assuming the airplane is aligned with the runway, would be (inverse tangent xwind/TAS):

crabangleea8.jpg
[/URL][/IMG]
 
A long, wide runway goes a long way toward allowing landing in high wind conditions. With enough pavement, it's easy to compensate for gusts, surrounding terrain, etc. As wind speed begins to reach/exceed stall speed, the more difficult issue to deal with is maintaining control during taxi. At the same time, I find that surface winds much over 35kts. usually result in some pretty uncomfortable flight conditions in those last 2000-3000 feet AGL. This is particularly true if you're riding as passenger rather than as pilot.
Terry
 
AlexPeterson said:
For 90 degree crosswinds of magnitude (at the aircraft) as shown, the crab angle through the air, assuming the airplane is aligned with the runway, would be (inverse tangent xwind/TAS):

crabangleea8.jpg
[/URL][/IMG]
Click to expand...
Actually, it is a bit worse than that. It is inverse sin(xwind/TAS), as the path through the air is not aligned with the runway, but instead it is along the hypotenuse of the wind triangle. So, if we have a 30 kt direct crosswind, with a 55 kt TAS, the crab angle is about 33 degrees.
 
n468ac said:
90 deg cross wind 25kts is easy ... but i did make it with a 35 kts 90 deg cross wind, I told my passenger i was going to make one approach, if we had to go missed i had alt airport with the wind right down the runway.
Click to expand...

The thread has changed a little over time so to add to my first post;

My land / go around is always based on if i have a stable approach, I've always found if i have a nice stable approach picture landing is easy. But if you are getting blown around, traffic issues, mechanical problems, distractions you need to go around.
 
One more consideration

All the above information is very helpful. I'll just add that I've found that when I land in the lee (downwind side) of trees or buildings that the management of the touchdown and initial slow-down can be very tricky due to the local turbulance those obstacles cause. This is not RV specific, more airport specific. I will even land partway down to runway to avoid that if I can.
 
Kevin Horton said:
Actually, it is a bit worse than that. It is inverse sin(xwind/TAS), as the path through the air is not aligned with the runway, but instead it is along the hypotenuse of the wind triangle. So, if we have a 30 kt direct crosswind, with a 55 kt TAS, the crab angle is about 33 degrees.
Click to expand...

Kevin, you are quite right! Actually, last night, after I posted it, I thought something wasn't quite right but forgot to back and look. Thanks. Corrected:


crabanglesd5.jpg
[/URL][/IMG]
 
I may have expended my limits today. I launched from OUN for ADS with the winds forecast to be dieing down but ADS was reporting 13G22 but minimal crosswind when I left. I needed to get home by Civil twilight (darn sport pilot limitations! My PP checkride is in Feb) and figured that if ADS was too windy, I could land at GLE where the winds were lighter (front had passed there earlier).

On final, tower called the winds 9G18. I decided to give it a go and landed fine between the gusts. If I couldn't get it down, my plan was to maybe try again then divert to GLE. Go-arounds are easy on the CT with the low stall speed (39), light weight (1300) and lots of power (13 lb/hr).

Fortunately it all worked out - or maybe I'm just getting better with the airplane.

TODR
 
I did my PP checkride with the max crosswind allowed in a Piper Warrior. (19mph I believe) Only caught 1 bad gust, but since I had to do a go-around anyways, we took that one. I didn't think about it then, but 2 notches of flaps instead of 3 probably would have helped a bit too.

Also got my lesson in flying the plane until it stops moving, not just when the wheels are on the ground. The runway sort of had a joggle bend in it. I landed, then the ground starts dropping away, and with all of that crosswind I started skidding sideways until I got my ailerons rolled in. :eek: While my instructor had drilled it into me, when you just don't see an effect its difficult to understand the need to do it. And that was just getting to the examiner! :D
 
Hummmmm

Personal Limits ...hummmm

Try landing in Marathon Fla.

Back in the 90's.......almost 90* to the runway, H e l l of a crab

Back in the 80's I saw my instructor fly a 150 backwards.....Go figure!!
 
the_other_dougreeves said:
Rules of thumb:

30 deg crosswind = 1/2 of wind
45 deg crosswind = sqrt(2) / 2 = ~ 70% of wind
60 deg crosswind = almost the full wind

Doug
Click to expand...

I've always taught a very similar ROT. It is based on the sine of the angle of the wind off the runway. The headwind/tail wind component can also be figured out based on the cosine of the angle. Here are my ROTs.

15 degrees off the nose = (.25 x wind) cross and almost all headwind
30 degrees off the nose = (.5 x wind) cross and (.9 x wind) headwind
45 degrees off the nose = (.7 x wind) cross and (.7 x wind) headwind
60 degrees off the nose = (.9 x wind) cross and (.5 x wind) headwind

Example: 20 kts 60 degrees off the nose gives you about 18 kts of cross and 10 knots of headwind. The calculated numbers are 17.31 cross and 10 on the noggin. Close enough for government work.

I typically blow off the 15 degree number and just remember .5, .7 and .9 for crosswind and then just reverse them for headwind. Clear as mud?
 
Gusts not steady state

cawmd82 said:
The last couple of weeks In the DFW area have seen all kinds of high and gusty winds including some relatively odd angles. Things here are usually pretty much NW-SE, one or the other. Today at one point ADS had 270/22 g30.

To the point....What are some of your personal comfort levels on winds for take offs and landings, with an emphasis on crosswinds?

Before the flames....Obviously one's experience will determine what is safe for that individual only--I am looking to get some dialogue on what various people find acceptable for themselves.
Click to expand...

I concur with what others have said -- the gusts (both in direction and speed) are much more limiting than a steady state wind with no obstructions nearby.

I fly off a 2000ft runway that's 40ft wide. It has a 300ft hill less than a mile off one end of the runway and a 1000ft hill a mile to one side of the runway. The other end of the runway sports some tall power lines and a bunch of water. The airport is 10 miles from the Pacific ocean (which generates a lot of wind) on the lee side of the Pacific Coast range. Here's what it looks like:

homedrome1-w.jpg


homedrome2-w.jpg


Needless to say, the winds here are never predictable. The airport is surrounded by 270 degress of obstructions, and the wind usually blows from somewhere in that 270 degrees, varying by 30-40 degrees in the gusts.

I have about 700 hours of tailwheel time and 50 hours in my RV. There are a lot of days that I don't go flying. On the days that I do, my worst landings are almost always back at the home drome.
 
cawmd82 said:
The last couple of weeks In the DFW area have seen all kinds of high and gusty winds including some relatively odd angles. Things here are usually pretty much NW-SE, one or the other. Today at one point ADS had 270/22 g30.
Click to expand...

Want to see a really odd angle? Taxi onto RWY 33 and stay to the right side of the runway. Point the nose of the plane to a heading of around 290, put in a little left aileron, then take-off!
 
Better than some bigger airplanes

I landed today in front of a turbine Air Tractor. The wind was reported 25 gusting to 33 knots as I landed. The Air Tractor was right behind me so I was looking for him to taxi in after I shut down. But he didn't and didn't.

Finally he appeared taxiing slowly crosswind but when he tried to swing around downwind to park, he couldn't. After a few tries two guys came out and held on to a wing tip, he still couldn't turn around. Then another guy came out. With three big guys holding back a wingtip he got it swung around, even not if exactly where he wanted to.

I'm guessing that that airplane doesn't have tailwheel steering, and with the big vertical tail he just wasn't willing to use the power and braking that would be necessary to swing that tail through the wind.

I didn't even have to use the brakes, and I'm pretty sure an A model would have had no problem, although it would have had to use lots of brake.

Maybe they figure ag planes aren't normally going to have to operate in windy conditions?

Pierre; poor operating technique or airplane design limitation?
 
I'm not Pierre, but just because it's a turbine air tractor doesn't necessarily mean that everything works as it should.

Working airplanes such as those might just not have the best brake systems or even other systems. The airplanes are in the air a lot and more prone to mechanical issues. I've never flown Ag but I did fly banner planes for a few summers way back when. Our airplanes flew daily for probably 8 hours or so, with lots of ups and downs. Maintenance issues were always an issue...particularily brakes. I've flown Stearmans and Cubs that had less than perfect brakes, and quite often required doing a 270 in order to go in the direction I wanted to go.

I used to own a Citabria that while it was a blast to fly, was a pain in the patoosh to taxi around in with a stiff crosswind. I suppose some airplanes simply have worse weathervaning tendencies than others.

So it really does boil down to personal limits, equipment types, tailwheel vs. nosewheel, airport and runway conditions, obstructions upwind of the touchdown area, gust factor, etc... I find anymore that it's just not fun to go up and get beat up in the air when it's that windy, so I usually take a pass and wait for a smoother day.:rolleyes:
 
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