Wind gusts, and other wind phenom.

[Toothcarpenter]

I have been wondering what is Microburst? What is wind shear? In my work as a dentist, it has been shown, with colored water in the devices the dentist uses, how splatter and bounce of particles, can help us understand infection control. I wish the wind, had color, so we could see it. I understand and can picture wake turbulence. I have tried to visualize such wind Phenom. I remember flying intentionally thru what we called dust devils, with my J3C65 when I was a kid, landing out in the wheat fields of the Palouse in Idaho, and Washington. It threw you around, but never to the extent of loss of control. There was a while back, a fairly sobering thread, of near loss of control, in wake turbulence, in the event of taking off right behind another cub at Johnson Creek a year ago or so. The reason I raise the idea, is that that this last Thursday, there was a crash of a Husky, on take off, at Moose Creek, Idaho. Media(who can trust them to get it right) said a gust of wind, flipped the aircraft over, and it crashed and burned on the runway. The passenger survived. I have been tossed around in turbulent air a few times, such that it made me afraid. One time, in cruise, with the wind behind me, flying too low, over a ridge, I thought I was going to be turned over upside down. Maybe over reacted, but it seemed a big time problem, till the thing finally started to come back around. I have not experianced being flipped around near the ground, on approach or departure, such that the aircraft seemed uncontrollable. Have any of you guys and ladies, been tossed around by wind on approach or departure, when speeds were in a comfortable , and safe range, such that the aircraft was uncontrollable, or nearly out of control. I am sitting here, wondering what I have yet to learn, that hasn't been served up to me already. I did know the pilot, and so likely have been impacted, in a way that I may be over analyzing it. Anybody know anything, or have experiences, and lessons, they are willing to share comments about here? Thankyou! Ed

[Bill Ingerson]

I remember flying with my friend in a 170 in the shadow of the Olyimpic mountains one time. We were about 1200 feet up and flying the plane slow because the weather in front of us was getting bad, poor visibility. I know my friend, who also was giving me a check ride wanted to see just how far I would go before saying lets go back. About the time I was ready to say that, a micro burst of wind hit us so bad that I could not see the dash and gauges clear. You shook so bad you couldnt read any of them. My friend just reacted by instinct and grabed the wheel and pointed the nose down and quick 180 turn, probably lost 500 feet but the plane settled right down after that. and we landed at a nearby airport. wish I could see the wind coming also, it had to be like driving a car into a water fall. Made me remember what to do next time.

[Iflylower]

Yes, to all of that. I picture my favorite trout stream when I want to picture what the wind is doing and what it looks like. Fluid dynamics.

Mother nature sure can dish out more than the performance of our aircraft can handle. Best way to go is armed with knowledge and judgement. Sparky imeson and "Mountain Flying" is a great resource for brushing up on those topics.

This months AOPA mag has a story on strong Rotor clouds.

Quicky, windshear is two opposing wind directions meeting. They can be vertical or horizontal. Picture two streams or rivers coming together and the resultant eddys or swirls.

[8GCBC]

http://en.wikipedia.org/wiki/Windshear

http://en.wikipedia.org/wiki/Microburst

http://en.wikipedia.org/wiki/Thunderstorm

http://en.wikipedia.org/wiki/Coldfront

http://en.wikipedia.org/wiki/Cyclone

[Toothcarpenter]

So; other than knowing the types of meteorological conditions that spawn these violent currents, like every warm summer and fall afternoon, detection is a game of chance. I think in the future, when possible, I will carry a bit more speed, in lifting off and climbing out, as well as most of the approach. Cool early mornings, and carb heat anyone?

[8GCBC]

I was flying a C172 from Honolulu to Molokai during the passage of a winter cold front (not a good idea). The ground speed was about 47 knots on a heading of 097 at 3000' AGL over the ocean. Estimated winds aloft were about 50 knots! The ATIS at Molokai reported winds at 270/005 kts.! Almost calm wind. The tower was advising that a huge shear just came through.

The windshear factor on approach was going to be about 55 kts from 097 to 270 during the 2000' descent. There was no way I was going to fly into a shear like that, the tower agreed and I turned back to Honolulu to beat the windshear back home, then landed fine!

[mvivion]

So; other than knowing the types of meteorological conditions that spawn these violent currents, like every warm summer and fall afternoon, detection is a game of chance. I think in the future, when possible, I will carry a bit more speed, in lifting off and climbing out, as well as most of the approach. Cool early mornings, and carb heat anyone?

Not really. There are most often clues.

If it says thunderstorm on the side, you can bet there MAY be some serious outflow from the thing, depending on the stage. Best to stay well away from thunderstorms...way away. MANY pilots have met their downfall flying into or close to thunderstorms. Complicate that by thunderstorms in the mountains, which adds terrain effects AND often the requirement to SHARPLY maneuver to escape bad air, and you've got a really ugly scenario.

Wind in the mountains is GOING to cause turbulence. Everyday mountain turbulence is pretty easy to envision. It's when that turbulence starts mixing with convection caused by heating of the surface that things can get a little harder to visualize, and more dangerous. That's why most mountain flying experts will tell you the best bet is to get your flying all done either early in the day (before the heating really kicks in) or late in the day (after the sun's below the ridges, and things are cooling off).

As 8GCBC notes, if you're around weather reporting stations, check the weather at various places (XM weather in the cockpit is invaluable there) as well as the wind aloft. Very Different direction/velocity wind on the surface as compared to aloft?? There's going to be a shear layer somewhere in there.

Micro bursts are much harder to predict, but by definition, they are small and transient in nature.

To me, one of the most difficult tasks that a pilot NEEDS to do, is to continue his/her education about flying weather, as long as you continue to fly airplanes. I'm still learning, and there's a lot more to learn, but much of it is pretty basic physics.

MTV

The scientists are still learning about microbursts, which can be scary.

[8GCBC]

I was told that some surface based windshear detection systems simply have anometers in different locations that detect wind velocity/direction differences.

Also, pilots on final will report airspeed changes. i.e. "+10 knots at 100' ". if you hear this on the radio....The pilot had a headwind burst which raised his/her airspeed 10 kts at 100 feet AGL. If you hear "-10 knots at 100 feet " The pilot lost airspeed (-10 kts) and it was a tailwind shear (which can really hurt with loss of altitude/control).

Roll clouds off a mountain are easy to see. The air is going up (cooling on the wave peak) and condensing, then descending (warming and changing the dew point) which makes clear air in the trough. Same as an ocean wave.

[dougc905]

Hey Ed, seeing as you are in Idaho, you should pick up a book on mountain flying. I am reading Flying the Mountains by Fletcher Anderson. It has a detailed section on weather phenomenon with an emphasis on what you will encounter in the mountains. I'd recommend picking up a copy. ISBN 0-07-141053-8 ..Doug

[sierra bravo]

I think in the future, when possible, I will carry a bit more speed, in lifting off and climbing out, as well as most of the approach

Wind shear only occurs when there's wind. Call it whatever you want but for me I'm always aware of the affect of wind rotors, especially so for local ones from nearby hills and trees. When the winds are blowing and I'm on the lee side of obstacles I carry more speed to touchdown and build more in ground effect before initiating a climb. When the winds are light I'm not concerned about it.

[Litecub]

wind_damage.jpg I taxied into a dust devil this spring, was picked up, rotated 90 degrees counter clockwise abruptly and violently slammed down upside down. It took me some effort to get my head, which was in a helmet out of where it was wedged in the V brace and collapsed top deck. The day had some convective activity in the area coming off the local mountains with rapidly warming spring air and about a 5 mile an hour wind. After the event I have talked to several people about these wind occurrences and heard of 5 other aircraft damaged by them in the local area over the years, 3 of which were tied down. The insurance adjuster had 3 claims before this one in Alaska. Not easy to see these coming at you until to late. I saw the dust erupt where I was taxing, then gravel started to strike the plane, the left wing picked faster than any roll rate I have experienced in a Cub, the plane pitched forward rotating with the vortex and then upside down. It happened faster than you could describe it with no response to controls.

[Toothcarpenter]

Wow! Litecub. Iv'e had dust devil throw dirt, and little tiny rocks at me, out in a wheat field. Never knew, it could/would flip you over. Makes sense though. Glad you are ok. Pretty sure, I'd need my brown pants for that ride.

[spinner2]

I've had the wind snatch my right wing and jerk it down in two different Cubs. The first time I was about 1000 ft agl flying in a straight line at around 55 mph waiting for another Cub to land.

The second time I was coming into land. There was some wind shear at the tree top level. I anticipated it and kept my speed on final faster than my normal. At about 50 ft I suddenly was looking at the ground from a steep and twisted angle.

In both cases it took full left rudder and full power to come out of it. Because I was so close to the ground the second time I thought I was going to crash. I didn't and made an ordinary 3 point ski landing a few seconds later.

I have no explanation for the first incident. The second one one was windshear combined with bad luck then immediately followed by good luck. The wind was blowing about 10-15 as a quartering from the left headwind. Perhaps lots of sun and snow and dark trees next to each other caused some weird sinking too?


Sent from my iPhone from the middle of nowhere using Tapatalk

[sierra bravo]

Pilots shouldn't be surprised by unpredictable wind currents on the lee side of obstacles. Here's a good computer model of what happens to the air downwind of an obstruction.

http://vimeo.com/9603170

My Sunday flight home saw departure strip winds at 30mph blowing 30*+ off runway heading over tall trees. Ride 'em, cowboy.

[Toothcarpenter]

It sounds stupid to say it; It seems that the common factor of low speed, is often a part of the incidents, which have been described here. I think we can, standing on the ground, intuitively tell the differences between a steady breeze, and intense gusts from a bunch of different directions. This is usuially also somewhat obvioius when flying. Surely it pays to keep our guard up all the time there is wind, or potential of wind. I used to say, every landing in the taildragger, is an adventure, meaning I intend to be ready for it to take off in just about any direction, at any time during landing, and I will not relax, until it is stopped.. Now it seems, better said, every flight is an adventure. It has been mentioned here, of the take offs at minimum airspeed, with nose high, low airspeed climb outs some of us like to impress ourselves and others with. Unless absolutely necessary, I have quit hanging it on the nose, just because it's fun. I think I have had too much faith, that it will keep running, and nothing is going to happen. Things keep happening to the best of them. Eeyore, said something like " the thing about accidents is, that you aren't haveing one, till you are having one."

[sierra bravo]

Toothcarpenter, add another dimension to your summary. Consider the gusty winds and the unpredictable nature of being downwind of some interfering structure. As the plane is low and slow and gets tossed about you might find the coordination a bit off. You might find yourself making control inputs that are met with an unexpected gust that is sympathetic to the control input. Do some thinking about uncoordinated stalls at low levels and factor gusty, turbulent ground winds into the picture. Airspeed is your friend when you're bucking the wind.

[S2D]

Airspeed is your friend when you're bucking the wind.

Now guys remember, the airplane doesn't know any difference. It is in a solid mass, it could care less if you are flying with the wind, into the wind, turning upwind or downwind. That is only a ground reference, the airplane isn't looking at the ground

[mvivion]

Troublemaker

MTV

[8GCBC]

Airspeed into headwinds can be a significant factor on range prediction. Especially in a slow aircraft.

Over Texas, June '09, I had a ground speed of 45 knots! Could only go from Dalhart to Tecumcari that day! That night the town was thrashed with a tornado! The twister missed the airport and I left the next day to Arizona (nice weather, except the smog over Tucson).

[8GCBC]

"Sierra Bravo's" post made me think about wingtip votices:

[NimpoCub]

Consider the gusty winds and the unpredictable nature of being downwind of some interfering structure.

Well, I don't "do" wheels, but this reminded me of an experience in the wind...
I'm cruising on two wheels, following one on 18 wheels. Strong wind from the right, I'm leaned into it a bit.
Time came to get around this obstacle & "giv'er" a bit more.
I drift into the left lane, & as I get abreast of the hind end of that thing, the wind quit.
Hola, but I manage to stop closing in on the side & get a parallel heading. Anticipate the wind again when I pull ahead.
Miscalculate my correction maneuver by a few nanoseconds & get unstable for a bit again.
After my heart rate slowed a bit I thought "What a rush!"

[Martin's]

" Have any of you guys and ladies, been tossed around by wind on approach or departure, when speeds were in a comfortable , and safe range, such that the aircraft was uncontrollable, or nearly out of control." Sorry about your friend. Seems like those of us with active friends pay a price...losses. My husband and I have suffered some tough losses of good friends. Some flying. Some were very good pilots. Microbursts suck. Trying to outrun a thunderstorm, a wet microburst sounds very plausible. The dry micorbursts are sneakier. Unless you are in a dry area (where you can see them approach in blowing dirt) they are invisible. We had a C182 blow over on us on take off in a country with good green grass. Couldn't see it coming. We were taking off with a 5 -10 kt headwind. The micorburst hit us instantly with a 70 kt quartering tailwind. I've thanked God many times, that it wasn't seconds later when we would have been at or near Vr. It would have cartwheeled us and we would not have escaped uninjured. The C182 was flipped and required extensive rebuilding. But still, aircraft are easier and cheaper to repair than people. We also experienced a dry microburst in a dry area. Saw it coming and tried to out run it to our hanger. Won't do that again. I'll fly to another airport and wait for it to pass. Landed on the ramp with a 20 kt headwind (short landing in a Cub), were hustling to push it in the hanger when it hit. Another 67 kt gust that tore off roofs and ripped up near by trees by there roots (leaving trees right next to them). I don't know how, but by the grace of God, the hanger blew apart, but our Cub was left right side up...even though my feet were lifted off the ground while hanging on (the things we do for love of a Cub). Microbursts are awful. I guess we just fly and know that there is a small possibility that something completely out of our control can happen.

[SC3CM]

Several years ago I was flying my Saratoga (fixed gear) to NY (KHPN) once or twice a week for work, and got pretty comfortable with the traffic, approaches and operations there. One day it was pretty stormy and there was windshear reported on ATIS as well as a couple jet's on approach giving the +/- XX kts. Had I not been going for work I would have turned back.
I thought all would be fine, just bumpy, so I carried extra speed, flew the approach at 100kias only used 2 notches of flaps and was high and steep. The runway is plenty long. I crossed the threshold at maybe 100 feet AGL and the bottom completely fell out from under me. The right wing and the nose dropped, I was yawed to the right quite a bit and if I wasn't in a 90 degree bank I was darn close! With full power and yoke full left and forward I was looking eye to eye with the crew of an Air Tran flight I believe. Somehow things straightened out enough that I got the gear under me about the same time as the numbers. The plane hit so hard I smacked my head on the throttle quadrant, bruised and cut my hand on the panel, then found myself in a steep nose up climb.

Screw the 'mandatory' go around after a big bounce, I nosed over, saw plenty of runway so chopped the power and landed. Mostly because I really didn't feel like flying anymore that day, but also thought I hit the prop and right wing because there was a lot of noise. I still made the turnoff on the intersecting runway.

As I cleared the runway the airline crew radioed the tower and said they were going to hold and asked if they could send a truck to look for pieces of my plane still on the runway.

When I parked and managed to fumble the engine controls enough to shut the plane down I got out an first checked to see how bad the wing was damaged, there was NO damage to my surprise. The prop had no dings either. The nose and right wheel pants were broken though. The mechanics found 3 broken gear bolts on the right main and one broken on the left. That was the only damage to the airplane.

It took me a bit longer to make it out of the FBO and off to the train station for some reason, and I ended up cancelling all client meetings except for my dinner appointment which really turned more into a drinking appointment

I am convinced if I were not in the tank of an airplane that the fixed gear Saratoga is, the outcome would have been significantly more damage to both the plane and myself. To this day really strong gusty wind near the ground gets me on edge and I really don't enjoy flying in it.

On the t-storm/microburst situation, an old airline pilot told me if you had to land near a storm, to land toward the storm because any microburst or significant wind would be more likely to be on the nose than on the tail. A + 20kias shear on short final would be uncomfortable, but you're still flying. A - 20kias shear on short final in most of the planes we all fly would mean you are done flying. I'm sure there are infinite variables, but it's something to think about.

[spinner2]

Here's a link to an article in the Anchorage Daily News about a 206 on floats that 'cartwheeled' on landing. Sadly there was a fatality and the pilot says he thinks a microburst hit the plane after landing.

http://www.adn.com/2012/07/12/254004...tal-plane.html

[sierra bravo]

It was an interesting choice of words. We've had nothing but cool days in south central Alaska lately. The coldest July on record, in fact. And this accident happened at night. The wind was blowing steadily from what I heard. Not the conditions one would expect for a microburst. Mechanical turbulence is much more likely. In any event the accident took the life of a very well liked woman. My sympathies to her family and friends including the pilot.

[Toothcarpenter]

Sierra Bravo; What do you mean by mechanical turbulence? Rolling air currents, eddy currents, on the lee side of trees or terrain on shore? Cold water, and warm air meeting? Thanks!

[sierra bravo]

There's lots of printed info on mechanical turbulence. Google it. Here's a good article from a respected source. http://navyflightmanuals.tpub.com/P-303/P-3030106.htm

In Homer the wind was blowing off the bay, up the bluff/hill to where Beluga Lake sits in a depression. A perfect setup for mechanical turbulence. The prevailing wind was blowing across the landing lanes on the lake that night at 21kts from what I read. Not horrible conditions but enough to warrant caution. Sometimes we're just in the wrong place at the wrong time. Y'all carry seatbelt cutters, right?

[N5126H]

If you get a chance, go to the Deutsches Museum in Munich and view/play with the hydraulic engineering fluid flow effects exhibition. It will teach you more in one hour about wind and currents than you could experience in a life time.
http://www.deutsches-museum.de/en/ex...s-on-exhibits/

[Dave Calkins]

An easy way to learn what our invisible air is doing is to see the airmass as a giant "river of air". We are flying in that river. If you can visualize (make up in your head) what you think a real water river would do, it will help.

Paraglider pilots fly very low-speed and turbulence-effected aircraft, yet they search for lift/thermals and are often in horrible turbulence. They experience in a couple of hours of flight more than a "real" pilot will experience in many years of flying. "river of air" theory is taught early to Paraglider and Hangglider folks.


Brian. Can you explain WHAT is causing the downwind turn phenomenon. Please. I would like to define it.

Dave......in the mountains and valleys, and behind the rocks and pools. ....and aware, but always searching........

[S2D]

Brian. Can you explain WHAT is causing the downwind turn phenomenon. Please. I would like to define it.

I think Gordon's (12Geezer) wind speed gradient/ gust geometry pretty well summed it up.