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Reading the wind


mausermolt
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Im currently flying in an area where reading the wind is EXTREMELY difficult.

Sometimes there is a bit of smoke coming from something burning in the city, or a flag on a building.

Although its seems like the wind changes direction about every 50 yards or so around here.

But normally im not landing around the city anyway.

So far ive been going off what the helicopter is doing like when i get that big "push" in a turn.

Anyway just looking for more ideas and how ya'll read the wind!

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Much more info on reading the wind from the water is available by researching Seaplane operations.

 

For winds under 10 KTS you'll have to learn to look for the "cat's paws" as they develop and spread. A reservoir or big duck pond can be used in this way. For larger bodies of water the "white caps" will develop in winds over 15 KTS. At 18 KTS look for the windsurfers.

 

Those "rain bird" type sprinkers on the golf courses and strawberry fields also work well for indicating wind direction.

Edited by Little Red 22
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My flight instructor has taught me a handful of visual cues...

 

For starters, if your ship has a GPS unit, compare your indicated air speed vs. ground speed. This is my usual go-to as it's the easiest way to determine if I have a head or a tail wind, but it's sort of cheating and it doesn't work so well if you have a crosswind - generally if we are landing off airport, I will check the difference between GS and IAS during my high re-con.

 

Visual references:

-smoke

-bodies of water (a pond, lake, etc to check for surface wind)

-broad tree leaves (if you can see the shiny side you are upwind, and if you see the dark side you are downwind - this was one of my favorite tips, but there aren't always broad leaves around, especially now in the winter time.)

-trim (this goes with "what the heli is doing")

 

 

Not sure if that helps in your area, but up here in the Pacific Northwest we generally have a lot of cues for wind, these are a few that help me.

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Your GPS airspeed works well, I use it all the time (If you're near the ground) You can also do a perfect orbit holding the same degree of bank around your landing spot. The wind will push you one direction or the other...dont look at your spot, just maintain your bank angle and then look and see where you are.

 

If you really can't tell, then its probably less than 10 knots and most birds can handle that downwind...depending on all the specific factors of course (weight, DA, approach, etc). When in doubt, most areas have a prevailing wind direction that you can count on.

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K, you already know all the theory from the books about estimating the wind. The problem comes in the real world when the wind is light and all the usual cues (smokestacks, ripples on ponds, cows facing thisaway or thataway etc) aren't available. If you're in a ship like a...ohhhhhh...grossed-out R-44 you might want to take as much advantage of the wind as possible, so you're looking for every little puff and you'd rather be into it than have it on your tail during the approach, right?

 

The short answer: It's very tough sometimes to gauge the wind. Sometimes you just have to give it your best guess. You know where the prevailing wind is coming from (from your GPS gs readout in cruise). But surface wind can vary a lot.

 

And now for the expanded version!

 

As you do your high recon, maintain a constant airspeed. If there is any wind at all you'll feel its effect on the ship as you go around the circle. Keep it in trim and watch the drift angle across the ground. The key of course is to not be in a rush. I hate being in a rush. I hate watching pilots who are in a rush. I mean, what's the hurry? Are you on fire? Oh wait, maybe *YOU* shouldn't answer that one ;)

 

If the wind is so light that it's not readily apparent as you do your high recon, then it's probably light enough to not freak out over. If you're really, really heavy, then begin your approach and get down below ETL early. The helicopter will "tell" you if it's into the wind or not. If it's squirrely in yaw and the rate of closure doesn't seem right, then something's obviously wrong. If things don't feel right, go around and figure out a better way. Initiate the go-around *before* getting so low that you're committed to the site.

 

Going into my (former) boss's hunting camp at night, there were few lights and no wind indicator. Luckily there's not a whole lot of wind at night. But sometimes there would be, or sometimes I'd just guess wrong. Sometimes I'd come in the "usual" way and it just wouldn't feel right. So I'm not proud; I'd abandon the approach and try it from the other way. Did that more than once. We were ALWAYS heavy as f*ck in that little 206B. You just cannot rush, and you cannot get into a mindset where you have to land *this* way.

 

So...

 

1) Never assume that you *know* where the wind is coming from. Chances are you'll be wrong.

 

2) Come in slow. I know you Robbie guys like to come screaming in fast, but you gotta break yourself of that habit. Pretend it's an S-58 with a couple of blown jugs and severe carb ice and you're landing to the IGA or Super Foods or whatever it was parking lot in Brewster. It took me a long, long time to change my philosophy that I *had* to keep it out of the H-V on approach. Screw that! Keep it level, and keep it under control. Fly a profile that will require little or no power-change as you come to a hover.

 

3) Do a proper high/low recon *every* time...or any time you're heavy and having some headwind is critical.

 

These techniques served me well when I was with PHI in the Gulf of Mexico for 13 years and made, let's see...7,000 hours times 5 landings per hour...oh, 35,000 landings to offshore oil platforms. Or thereabouts.

 

Oh, and next time you want to know something like this, just hit me up on Facebook. I could've fit this entire post into one (long-ish) chat message. Okay, maybe two.

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Sometimes you just have to give it your best guess.

 

If a downwind approach is what you're most concerned with avoiding, look at it this way,...you still have a 3 out of 4 chance at guessing right!

 

By the way, as a Robbie Guy, I'm proud to say that one of the biggest critisisms I get from CFIs, is that I come in too slow!

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Remember what the winds were when you left? Dial up some AWOS and ATIS services enroute, too. Use these as a starting point for an assumption.

Get out your E6B or use the GPS calculator, and remember the wind turns right (rule of thumb) as you climb. It'll turn left as you head down, all things being equal.

Why would the wind vary otherwise? Lots of local temperature differences? Consider that as an adjustment to your starting assumption, especially with light and variable conditions.

Did you cross a front enroute? Nearing a front? That nullifies your starting assumption. Use some other weather stuff memorized for your last written...

Will the terrain be a factor? Mountains, structures affect the wind, especially as you descend. Big factor with big buildings, mountains.

 

The assumption is wrong if it varies from what you're seeing in the immediate vicinity- smoke, flags, bodies of water, etc., use what you see.

 

Once you have an estimate of the wind and good, clear approach and departure track, emphasis on survivable forced landing areas a priority (having someplace to go is better than crashing pointed into the wind), then fly to and hit the "angle". Fly the descent as slow as possible on the approach. Any- repeat ANY- discernible change in attitude means something is wrong or the skids are dragging. If you're wrong, abort and start a new plan. If you're not going around occasionally, you're over confident. A slow approach makes that abort obvious and easy.

 

Never flown R 22, but a power failure (in any aircraft since the mid-1920s) and auto in the approach is much less likely than a PIC brain failure, slow approaches make that easier to abort, and have the bonus of taking much less power.

 

Look at it this way-

Hit your power limit and ETL at 15-20 feet above the obstacles and you have choices.

Hit them both 15-20 feet below the obstacles and you have a problem.

Edited by Wally
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lol wow thanks guys! Nearly Retired: you should really look into being an instructor! they way you personalized that was spot on ol' chap!

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My flight instructor has taught me a handful of visual cues...

 

For starters, if your ship has a GPS unit, compare your indicated air speed vs. ground speed.

 

Just remember, if you're flying when your indicated and true are different, you can't just reference your indicated and your ground speed. You have to figure in your true airspeed and then you can use your GPS to calculate a wind.

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