When can a 1 knot windshear lead to disaster?

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pelmet
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When can a 1 knot windshear lead to disaster?

#1 Post by pelmet » Mon Oct 02, 2017 7:37 pm

During the slowest flight contest in Alaska and you are half a knot above the stall speed.....

https://www.youtube.com/watch?v=wWrG3_YqGZc
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Re: When can a 1 knot windshear lead to disaster?

#2 Post by pdw » Tue Oct 03, 2017 6:52 am

Looks like the component at first was a very light headwind straight-on down the runway but then it moves over to the right Xwind and increases during that event.

The engine power can be heard to vary, in keeping slow-as-possible (video-version with sound).

The moment comes where the gust passes and power immediately increased for airspeed while drifting/drifted left .. so lets up on right rudder for show positioning (keeping straight). Unfortunately heavier right rudder had to remain applied to counter left roll tendency of increased propwash of the added power after the gust has passsed, esp when that slow. The new right crosswind strength/angle likely not expected, .. where-in is tricked for just-a-sec by the shear's power requirement, ie lets up inadvertantly on right rudder to stay course in a trickier process of keeping it stable.
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Last edited by pdw on Tue Oct 03, 2017 12:24 pm, edited 3 times in total.

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Re: When can a 1 knot windshear lead to disaster?

#3 Post by pdw » Tue Oct 03, 2017 8:48 am

KAKTALKE2 wx-station data shows village component (just off to the left of rwy1) every 5-6 minutes. The sound video captures ongoing power adjustment in yawing to the right (cauing reduction of right rudder when needs it most ?) just before "left wing stalls"(ASN).

Occurrance 12:30pm May21 runway one 11M/ 27T.

12:23pm: NE/05T 14.8kph gusting 15.8kph

12:29pm: ENE 6.4kph gusting 11.9kph

NNW 3-5kts (40deg left) before "12:23" and after 12:29 ESE 2kts / right 90deg (TALKE2 wx-station data). At half past the hour, the incident is 1/2way between the Airport's noon/hourly metar 05/8kts and 0000kts at 1pm (airport wx-station located on east side of rwy1). The town's wx-station is very close to this action, only a mile off the left wingtip (west of the runway) in the video.

When looking at it with the perspective of "the straw that broke the camels back" ("When can a 1 knot windhear lead to disaster?"), here the ENE 6.4kph gusting 11.9kph (gusting 3-4kts) is a 30-40deg right crosswind component approaching 12:30pm. Less right-rudder suddenly needed to stay straight in power decrease (during the increasing Xwind/IAS) .. and next, power again added for low airspeed right after .. with abscence of the right rudder because right there wants to aim the nose a bit left to stay on centreline; ie: in the video no right rudder-deflection noticeable at all right there, even as the left wing slowly starts the drop ..
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Re: When can a 1 knot windshear lead to disaster?

#4 Post by Meatservo » Tue Oct 03, 2017 9:03 am

I will not be contributing to the “go fund me” account to help Tom rebuild his plane. A “slowness” contest is stupid. It’s like having a contest to see how close you can hold your nose to a running bandsaw. There is a totally predictable limit with a totally predictable outcome. I guess he won the contest, because clearly you can’t go any slower than he just did. At least, not in that kind of plane. Congratulations Tom!
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Re: When can a 1 knot windshear lead to disaster?

#5 Post by rookiepilot » Tue Oct 03, 2017 9:22 am

Go Fund me accounts are seen for everything these days.

Pay for you own bloody hobby, dude.
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Re: When can a 1 knot windshear lead to disaster?

#6 Post by pdw » Tue Oct 03, 2017 9:51 am

Looks like might have value for lesson material.
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Re: When can a 1 knot windshear lead to disaster?

#7 Post by Chuck Finley » Tue Oct 03, 2017 10:09 am

Let's wait for the report..
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Re: When can a 1 knot windshear lead to disaster?

#8 Post by lownslow » Tue Oct 03, 2017 10:10 am

Meatservo wrote:A “slowness” contest is stupid. There is a totally predictable limit with a totally predictable outcome. I guess he won the contest, because clearly you can’t go any slower than he just did. At least, not in that kind of plane.
Except there isn't a predictable limit. It's a highly modified airplane and there are probably gains (losses?) still to be had by changing more stuff, just how his stall speed is already appreciably lower than a stock Super Cub from which his plane is based. Different airfoil, reprofiled slats, VGs, thrust line, strip weight, add power, or whatever. Everything gets tricky right at the bleeding edge of what's possible, and competition breeds improvement.
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Re: When can a 1 knot windshear lead to disaster?

#9 Post by pdw » Tue Oct 03, 2017 10:19 am

Looks like some value as lesson material. Ailerons are useful when not yet stalled, yet concentrating on success in the event likely interferes with the quick reaction to neutral when it dipped below.

The way it spun around the left wingtip .. is something like the Cessna that spun left around the tree in Plainville.
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Re: When can a 1 knot windshear lead to disaster?

#10 Post by digits_ » Tue Oct 03, 2017 11:03 am

Does that mean he didn't have insurance?
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Re: When can a 1 knot windshear lead to disaster?

#11 Post by rookiepilot » Tue Oct 03, 2017 11:12 am

digits_ wrote:Does that mean he didn't have insurance?
So what? So the guy should do a Go Fund me account like someone who lost their house?

Not other people's problem you wrecked your plane.

Sheesh...............
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Re: When can a 1 knot windshear lead to disaster?

#12 Post by digits_ » Tue Oct 03, 2017 11:15 am

rookiepilot wrote:
digits_ wrote:Does that mean he didn't have insurance?
So what? So the guy should do a Go Fund me account like someone who lost their house?

Not other people's problem you wrecked your plane.

Sheesh...............
Not at all. He can do what he wants, but I find a go fund account for this a bit weird as well. Makes me wonder if he had insurance. If you do fairly high risk flying, like he does, you'd think he'd have insurance. If he does have it, it makes the go fund me account even more sour. If he doesn't have insurance, well.... then other people shouldn't pay for you trying to save a dollar.
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Re: When can a 1 knot windshear lead to disaster?

#13 Post by crazyaviator » Tue Oct 03, 2017 11:26 am

What does he pay his A/P to fix it ? $15.00/Hr. ? What an asshole !!
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Re: When can a 1 knot windshear lead to disaster?

#14 Post by sanjet » Tue Oct 03, 2017 3:57 pm

Flying that angle of attack 10 feet above ground was asking for trouble regardless of anything.
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Re: When can a 1 knot windshear lead to disaster?

#15 Post by PilotDAR » Tue Oct 03, 2017 4:37 pm

I'd expect that the insurance company would have exclusions for "competition flying".

If a pilot owner wishes to commit his aircraft to high risk, I guess it's their right - I won't be chipping in. I'd rather insure, and then fly within the terms of the insurance.

Yes, just a couple of knots of breeze can have a big effect. I was picking vertically out of a treed confined area in the MD500. My colleague suggested I turn around to depart west, but I had noticed a very slight whisp of breeze from the east. I allowed the rotor to catch that breeze as I topped the trees. The helicopter picked up a little, and the climb away was confident. If I'd gone west, I would have been trying to power through a downwind departure - however slight.
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Re: When can a 1 knot windshear lead to disaster?

#16 Post by GyvAir » Tue Oct 03, 2017 4:42 pm

digits_ wrote:
rookiepilot wrote:
digits_ wrote:Does that mean he didn't have insurance?
So what? So the guy should do a Go Fund me account like someone who lost their house?

Not other people's problem you wrecked your plane.

Sheesh...............
Not at all. He can do what he wants, but I find a go fund account for this a bit weird as well. Makes me wonder if he had insurance. If you do fairly high risk flying, like he does, you'd think he'd have insurance. If he does have it, it makes the go fund me account even more sour. If he doesn't have insurance, well.... then other people shouldn't pay for you trying to save a dollar.
From the video description:
Tom walked away uninjured, but his SQ2 was not so lucky. To make matters worse, the insurance application for the SQ2 was still at home sitting on his coffee table. Tom is a great guy who loves Alaska and aviation.
Many people at the Fly In asked if there was any way they could help Tom out. As a result, we have started a GoFundMe campaign for him. Tom gave his consent, but is in no way asking for a handout or contribution. He is a real Alaskan Bush Pilot and will rebuild his SQ2 regardless. For those of you who would like to help him out, visit the GoFundMe page and follow his progress.
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Re: When can a 1 knot windshear lead to disaster?

#17 Post by digits_ » Tue Oct 03, 2017 5:19 pm

[DELETED - Insurance not required, sorry!]

Anyway, good for him if people want to help him.
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Re: When can a 1 knot windshear lead to disaster?

#18 Post by Cat Driver » Tue Oct 03, 2017 5:48 pm

As I see it if it was a contest to see who could fly the slowest he was a loser because he did not complete the flight.
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Re: When can a 1 knot windshear lead to disaster?

#19 Post by photofly » Tue Oct 03, 2017 5:57 pm

Indeed. I'm not sure what to make of a contest where crashing and rendering your aircraft un-airworthy doesn't disqualify you from winning.
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Re: When can a 1 knot windshear lead to disaster?

#20 Post by ahramin » Tue Oct 03, 2017 6:01 pm

Amazing what the experts here can come up with. A homebuilder who pays AMEs $15 an hour to fix the plane he built ... :roll:

And he's flying ILLEGALLY :shock: Why don't you tell us what the aircraft insurance requirements are in Alaska digits_?
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Re: When can a 1 knot windshear lead to disaster?

#21 Post by rookiepilot » Tue Oct 03, 2017 6:13 pm

[quote="ahramin"]Amazing what the experts here can come up with. A homebuilder who pays AMEs $15 an hour to fix the plane he built ... :roll:

And he's flying ILLEGALLY :shock: Why don't you tell us what the aircraft insurance requirements are in Alaska digits_?[/quote
.
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Re: When can a 1 knot windshear lead to disaster?

#22 Post by digits_ » Tue Oct 03, 2017 7:42 pm

ahramin wrote:Amazing what the experts here can come up with. A homebuilder who pays AMEs $15 an hour to fix the plane he built ... :roll:

And he's flying ILLEGALLY :shock: Why don't you tell us what the aircraft insurance requirements are in Alaska digits_?
My apologies, looks like liability insurance is not mandatory in this case.
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Re: When can a 1 knot windshear lead to disaster?

#23 Post by pdw » Sat Oct 07, 2017 5:01 am

Cat Driver wrote:As I see it if it was a contest to see who could fly the slowest he was a loser because he did not complete the flight.
It's a different type of flying experience in the rough terrain anyway, where these type of fliers mostly go; so yes, the landing gets very disruptive to the certificate of airworthiness here .. but for the contest ?... if it landed on its wheels and doesn't touch the prop, with engine still running, no debris on the runway ?
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ps (Pelmet and Others who find this really interesting):
The "1 knot" measure needs qualifier for time too .. ie the rate .. such as whether 1kt per sec .. 5 sec .. or in 10. With any event there is the transition, however narrow it might be. You'll rarely get only a "knot" affecting your speed in an instant. Yeah ... so here it is .. about 5 or 6 knots looks-like .. where the whole increase affected it over 10 seconds (noting the lengthy right yawing in the video being compensated-for) and really only effective as less-than 1kt per sec.

Right after, the left wing drops .. which maybe already held a bit low and checked with the extra right rudder (left crosswind prevailing shortly before, which was expected) ?
The right gust/change unexpected then meant the "right aileron" (note right aileron position kept in video) is correctly utilized if needs right wing low against any right crosswind where reducing right rudder. Except, the left wing starts to drop while yawing right into it .. so immediately is "wrong aileron" then, while also luring 'abscence of right rudder' to counter right yaw, which gets too late for maintaining stability but tightens that amazing left arc back onto the wheels.
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Re: When can a 1 knot windshear lead to disaster?

#24 Post by GyvAir » Sat Oct 07, 2017 9:47 am

pdw wrote:... if it landed on its wheels and doesn't touch the prop, with engine still running, no debris on the runway ?
This is the new bar?
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Re: When can a 1 knot windshear lead to disaster?

#25 Post by lownslow » Sat Oct 07, 2017 6:45 pm

GyvAir wrote:
pdw wrote:... if it landed on its wheels and doesn't touch the prop, with engine still running, no debris on the runway ?
This is the new bar?
I sure hope so, then my record would be back to 100%! I've always been able to taxi all of my debris off the runway, after all...
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