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What's the best way to find the wind


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I'm looking for some advice on how to find the wind in confined areas in the middle of nowhere where there is no water to check ripples, no flags, smoke or tall grass, no birds or cows or horses. Just mountainous terrain with tall pine trees everywhere that just seem to bob back and forth in the wind.

 

I'm going for my flight test soon (finally) and I'm having issues with this. The way I've been taught is to fly an orbit around the confined area at a constant airspeed, altitude and angle of bank and see which direction you get pushed by the wind. I'm finding it very difficult to keep all three parameters constant so I can get a proper read for the wind.

 

I also know of the method of straight passes while comparing ground speed on my GPS to my airspeed, but I don't think I'm allowed to have my GPS on during the test.

 

I'm looking forward to your suggestions.

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If the normal ways don't work, you could always drop a smoke grenade during the orbit, or hike out to the usual areas where you practice and put up flags or streamers all over the place.

 

Or... If you are having a hard time maintaining airspeed in the high recon, typically in my experience it is due to a failure of the scan. So, if your relative groundspeed is constant in your orbit and you find yourself going really fast one way (on the airspeed indicator) and slow in another, that should point you in the right direction.

 

However, per the pts your airspeed shouldn't be changing that much so you might not want to go with that route.

 

Good luck on your checkride, and i am also curious to hear of other methods.

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If the winds are strong enough - say 10 kts+, the high recon orbit will be elliptical even without pinpoint speed/bank accuracy. If the winds are light - say

 

If you have the power, you could always come to an OGE hover above the highest obstacle and do a 360 pedal turn...

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If the winds are strong enough - say 10 kts+, the high recon orbit will be elliptical even without pinpoint speed/bank accuracy. If the winds are light - say

 

If you have the power, you could always come to an OGE hover above the highest obstacle and do a 360 pedal turn...

 

Yeah, what he said, but not the part about the HOGE.

  1. On your way there, be looking for wind indicators (lakes, crab angle, smoke, flags, birds). This gives you a starting point so you are in the position of confirming/modifying what you think, rather than figuring it out from scratch.
  2. Look at the terrain. Wind flows like water, sort of. And the wind behaves in somewhat predictable ways around flat terrain, pinnacles, valleys, etc. You can paint a mental picture, again, of what you think the wind should be doing. If the wind on the way there was 360 and your confined is at the mouth of a valley oriented 040, you can make an educated guess of where the wind will be.
  3. There's a figure of 8 recce that I've learned about. Do a loop that crosses your spot, for example, from east to west. Come back around and cross NW to SE. You're going to get a crosswind and head/tailwind on one of those passes. I've only read about this being applied when you're doing a many-pass recce, where this is an option for the initial pass, followed by a low recce and....
  4. If you really think wind is going to be an issue and you really don't know where it's coming from, you can do a "dummy approach"/low recce. Set up like you think you want to do the approach based on what you think the winds are, get down as if you were going to land, and go around well above ETL. On that approach, you should be able to learn everything you need to know about the winds and surface.
  5. No birds? Aren't there loonies everywhere in Canada?

 

Also remember you're looking for a wind direction: NE, S, "from over there", down the valley.... You aren't trying to figure out the difference between 045 and 060.

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Monitor your indicated airspeed and your ground speed when conducting your circling high recon pattern. If your ground speed on your GPS is higher than what is indicated, you have a general tail wind. If your indicated airspeed is higher than your ground speed, you have a general head wind.

 

That's pretty much the last resort if you have no other wind indicators in visual range.

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If the normal ways don't work, you could always drop a smoke grenade during the orbit, or hike out to the usual areas where you practice and put up flags or streamers all over the place.

 

Or... If you are having a hard time maintaining airspeed in the high recon, typically in my experience it is due to a failure of the scan. So, if your relative groundspeed is constant in your orbit and you find yourself going really fast one way (on the airspeed indicator) and slow in another, that should point you in the right direction.

 

However, per the pts your airspeed shouldn't be changing that much so you might not want to go with that route.

 

Good luck on your checkride, and i am also curious to hear of other methods.

 

What does "per the pts" mean?

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Monitor your indicated airspeed and your ground speed when conducting your circling high recon pattern. If your ground speed on your GPS is higher than what is indicated, you have a general tail wind. If your indicated airspeed is higher than your ground speed, you have a general head wind.

 

That's pretty much the last resort if you have no other wind indicators in visual range.

I don't think I'm allowed to use a GPS on the exam but I've been told you can tell by the "apparent" ground speed difference in each direction. That's a bit tough for a newbie like me to recognize though.

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Do you mean the crabbing effect of the helicopter will tell you where the wind is coming from?

 

Yep. In a strong enough wind, you'll be able to tell from your apparent ground speed for a head/tail wind, but your crab angle will work too.

 

To really get this, you need significant winds. I didn't really understand until my commercial, when my instructor took me out in 18 knot winds and had me shoot approaches to the same pinnacle a half dozen times from different directions.

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Start out by getting real familiar with the general localized wind patterns of the area where the operation is going to be conducted. Do this throughout the day so you can reasonably estimate the wind direction during a particular time of day.

 

With the above in mind and you find you are still having trouble during the high recon, go ahead and make your best guess and shoot the approach. If you find during the approach the airspeed falls off quickly, the trim string begins to go limp and you’re dancing on the pedals, then go around and try a different route. Getting it wrong during a check-ride is no biggie as long as you recognize it and take appropriate corrective action.

 

Furthermore, IMHO, you don’t want to sacrifice forced landing areas for being exactly into the wind. As long as the wind is off the nose, you should be good to continue the approach. Additionally, off-airport final approaches don’t necessary need to be straight lines so don’t be afraid to maneuver as necessary during the approach to maintain an advantage.

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  • 2 months later...

I'm flying in Africa at the moment and it is quite a challenge to find the wind direction if the weather forecast is a mere guess and the closest ATIS is some 300nm away. That is, if it didn't become victim of an elephant stampede ;)

 

I plan every approach some 10 miles away by finding wind indicators. Tall grass, water, smoke. If neither one of them is readily available (very often the case) compare IAS and GS. I know some FW bush pilots that use the triangle method: turn 3x 120° with a short S&L leg in between and monitor how your GS changes. From there they do some complicated maths and come up with a result that helps them to land without crashing ;)

The method works very good without the math, though. Even if you just do a short turn of 90° in one direction you can figure out where the wind comes from.

 

Example:

1. You fly N with +7kts GS

2. Turn W and find a +10kts GS

3. Turn NW and find a +13kts GS

4. Voila, your wind comes from your tail, SE

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Without using gps or ground speed...

 

Just fly an orbit at a constant speed (60 knots) and altitude above your landing area and note the power required to maintain you altitude and 60 knots. Least amount of power used will give you your direction into the wind.

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the best way is to come to a steady hover & let the ship 'weathervane' & you will feel it in the pedals.... However this is not the safest way,,,,i recomend good ole 'pilotage' (or good ole, ground reference maneuvers)-- turns about a point & keep eye on your bank angle

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When using GS from your GPS, keep in mind that when operating in high DA areas, even in calm winds, your GS will be higher than your IAS. Nonetheless, you'll still be able to see in what direction your GS is higher/lower while maintaining a constant IAS.

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