Wind Shear: How Concerned Should I be

[sblack]

Originally Posted by rvbuilder2002

I may be wrong, but my understanding is that wind shear automatically implies a sudden change in wind direction with a change in altitude.
Sudden changes in velocity but from the same or similar direction is just gusty conditions

You are correct. It is the sudden loss of energy that is the hazard. The RVs are good performers and that will help. Would not want to hit windshear in a c172 at max gross on a hot day.I personally would carry some extra speed on final as added insurance.

It really is an individual thing. Some folks love the challenge, others don't want to take a chance. If you are low time and not sure, perhaps wait untill you have more experience so that you are more sure of your limitations and your airplane's performance capabilities.

[f14av8r]

Wind shear at altitude is one thing. Close to the ground is quite another. Check the report, a report of shear at 2000 feet means you should be prepared for some turbulence and carry some extra speed on your approach to compensate if a headwind quickly turns into a tailwind.

Personally, wind shear above 2000' AGL means nothing more than seating the flight attendants, or consoling my wife, early!

[Chkaharyer99]

Originally Posted by lr172

I am a relatively low time pilot (200 hours) and have never flown when wind shear was forecast. I am planning my second x-country in my RV-6A (just out of Phase I) tomorrow and Wind shear is forecasted. The surface wind forecast is 20015G23 with WS017 / 21054. I don't know how concerned I should be with this. How dangerous is this condition in an RV? I have already experienced some decent turbulence already. In fact, yesterday I got thrown into a steep up / banking attitude. Pretty scary when it happened. I pushed forward pretty hard to be sure that I didn't stall. I had never had turbulence do that to me before.

I know to be concerned with Vertical WS associated with convective activity and think that I understand it and it's potential affects. However, this is horizontal WS, associated with wind gradients.

I appreciate any guidance you can provide me on managing the WS risk.

Larry

Larry,

I'm also low-time (under 200 hours TT with about 40 in RV's). You're question is a really good one which has stimulated me to do research on the subject matter.

Here is a link I found that will provide some really good insight on your question:

WIND SHEER

https://www.faasafety.gov/files/gsla...%20branded.pdf

A quote from the text:

Effects of Wind Shear on Aircraft

In its many forms, wind shear can change a routine approach into an emergency recovery in a matter of seconds.
An aircraft is affected by the change in wind direction/velocity because the wind also changes the aircraft motion relative to the ground. We will look at the effects of wind shear on an aircraft and on pilot techniques for coping
with a shear situation.

I really appreciate the comments by Jim - SMRACER. That's awesome advise from a very experienced pilot.

Fly safe!

[Kevin Horton]

If the shear really is at 1700 ft as forecast, the shear itself shouldn't be a safety issue. There will be some turbulence, and airspeed changes, as the aircraft climbs or descends through the shear. A wind shear at low altitude is more of a concern, because it can lead to airspeed loss at low altitude, or significant turbulence at low altitude, both of which can be a problem during landing.

The strong wind above the shear could be a concern in mountainous terrain, but not a big deal in flat terrain.

[lr172]

Thanks for all of the replies here with experience shared. I really appreciate it. First fo recast is now at 2000' with almost no direction difference, just a 40 kit speed difference. It seems that most of the problems would be above pattern altitude.

Larry

[springer]

Originally Posted by lr172

My concern was the wind shear. It seems that the wind direction is not much different and is mostly a speed differential. Does the WS really just feel like gusting or were the concerns posted above about the 15G23?Thanks for the guidance here.larry

You are correct as WS creates a speed differential. At my airline for example we could not land with a plus or minus airspeed change of greater than 15 kts when WS is being reported. I have diverted twice as a result.

[Vac]

Larry,

You might be interested in reading the low-level windshear section of the all-weather operations chapter of the training manual posted over on the safety page (there is a link in the Transition Training Syllabus sticky at the top). There is some discussion on page 311 that may provide some more insight.

Fly safe and enjoy your RV!

Vac

[bkthomps]

Had to land in Lynchburg VA right near the shanandoah valley on a windy day, I needed fuel- it had been a reasonably smooth ride aloft and I was headed to DC

Direct crosswind, 14G32, in a tail wheel RV4- I earned my beer that day, had to do a takeoff after taking on fuel- in hindsight, I should have flown to an airport further away from the mountains

[cattflight]

I had a very recent un-forecasted LLWS experience on a trip back to KAPA from Texas while crossing back into CO. Despite very smooth skies 2k' AGL, our intended fuel stop had surface winds at 24G36 at 80 degrees to the only runway. No thank you! I could see a storm building to the west so I presumed that was the culprit.

So we ventured on another 40 miles to an alternate fuel stop. Clear skies, light chop at 1k' AGL. ASOS was reporting winds at 15G22 about 30 degrees off centerline and about 70 degrees different than our winds aloft. This raised a red flag. Fuel was going to become an issue, so I made the approach. When we dropped below 500' on base leg (with a tailwind), all **** broke loose. The plane yawed 30-40 degrees off heading, banked 30 degrees, and I lost 15 knots in an instant. Thankfully, I had flown the pattern hot in anticipation of the sheer, but it was still an exciting condition to recover.

And this was without any forecast of LLWS! Now I really understand why, if they can forecast it, it shows up in the AIRMETS! Stay on the ground.