Windshear and light GA

[Murdoughnut]

I offered to take a Cherokee up to our MX base for an oil change today. Winds kicked up quite a bit even while I was doing my pre flight - gusting to 17kts with a 30-degree crosswind component. Within my safety margin. But when I started to taxi, an aircraft on final gave a windshear advisory of 20 kts. Tower reported that they had been getting windshear advisories the last hour.

With only five hours under my belt after 10 years away (230 TT) this pushed my safety margin a bit too far - I parked her and packed her up. Not second guessing my decision, but figured it was worth the question - is low level windshear of that strength enough of a threat to cancel a departure?

 

[gliderboy]

Windshear on departure has never bothered me, probably because you're at full throttle; but windshear while coasting in for landing at low throttle settings can get 'sporty'.
Nothing wrong with staying on the ground when you're in doubt.

 

[JordanD]

Windshear on departure has never bothered me, probably because you're at full throttle

In a Cherokee that can't get out of its own way? Eh...

 

[BobDDuck]

A 20 knot shear is more than enough to cause issues with a Cherokee. The full throttle bit does nothing to help you (because you've got no more power to add) and can only get speed by changing your pitch. On the approach you at least can throw in some power to hold airspeed.

All that aside, the potential for down drafts associated with shears would be my bigger concern.

 

[gotWXdagain]

20 knots shear in a PC12 is enough for me to seriously consider alternatives, the best place for a cherokee to be in that kind of conditions is parked in the hangar.

 

[Nark]

@Murdoughnut you made the right call.

Don’t look left and right at your peers here, because there is a massive disparity in experience. What I will do, shouldn’t be what a 230 hour pilot should do at times. Each situation is different, given the factors at the time make a sound decision.
Welcome to being an aviator, and simply not just a pilot.

 

[Murdoughnut]

@Murdoughnut you made the right call.

Don’t look left and right at your peers here, because there is a massive disparity in experience. What I will do, shouldn’t be what a 230 hour pilot should do at times. Each situation is different, given the factors at the time make a sound decision.
Welcome to being an aviator, and simply not just a pilot.

Thanks. It's just always a bit embarrassing when local flight school's DA-40 takes off over your head as you're packing up. But the leadership of my flying club was very supportive.

 

[EIR]

It's better to wish you were in the air while on the ground, than wish you were on the ground while in the air.

 

[JordanD]

Thanks. It's just always a bit embarrassing when local flight school's DA-40 takes off over your head as you're packing up. But the leadership of my flying club was very supportive.

Meh, there were plenty of times within even my own school where I'd cancel and see another plane taking off and I'd think "what the hell is that person doing?" instead of feeling embarrassed.

 

[killbilly]

Thanks. It's just always a bit embarrassing when local flight school's DA-40 takes off over your head as you're packing up. But the leadership of my flying club was very supportive.

I've had a couple moments like that in my past. When I wondered once, aloud, about something similar, my instructor pointed out that maybe the guy was a really experienced pilot. Or maybe he was departing the area, had a decent window and decided to get out and up.

Or maybe he was just an idiot.

Ten years later, teaching on my own, I've determined that all three scenarios (or some combination) are equally probable. None change how I make my own decision.

Nark is spot-on.

 

[denverpilot]

Have had some wind shear and microburst experience way back when I didn’t have enough to deal with it... somehow survived...

Cancelled some stuff later when I did have enough experience to deal with it... because it still ain’t fun and dents in the top of your head from the headliner contacting the headset hurt like hell...

If flying for fun, anything un-fun doesn’t even need to be a significant safety issue to put the airplane away for.

Flying for work, then you have to decide if that’s in your bag of experience can handle any particular risk. Gets all annoying with that “thinkin’” stuff. Smoke starts coming out of your ears. Annoying.

 

[CFI A&P]

Good call. Hypothetically, what is the max climb rate on that PA32 given the conditions ? 800fpm, 1,000fpm... The margin of speed between Vy and Vso isn't much when dealing with wind shear and downdrafts, especially when considering a 20kt loss at climb speed. Another item to consider is the wing loading and turbulence in those conditions, because the ride is going to suck. You might have found yourself regretting the decision to takeoff, even if you didn't experience fluctuations in airspeed.

On a more serious scale, the Dallas crash was a microburst with different equipment than a PA32, it had different performance, and today we have different knowledge and a better understanding of the phenomenon of wind shear. If someone hasn't sat through that lesson at sim school yet, it is worth your time to learn about it.

Delta Air Lines Flight 191 - Wikipedia

en.wikipedia.org

 

[moxiepilot]

Heck I don't like a 20 knot sheer in the 777.

 

[CFIscare]

I offered to take a Cherokee up to our MX base for an oil change today. Winds kicked up quite a bit even while I was doing my pre flight - gusting to 17kts with a 30-degree crosswind component. Within my safety margin. But when I started to taxi, an aircraft on final gave a windshear advisory of 20 kts. Tower reported that they had been getting windshear advisories the last hour.

With only five hours under my belt after 10 years away (230 TT) this pushed my safety margin a bit too far - I parked her and packed her up. Not second guessing my decision, but figured it was worth the question - is low level windshear of that strength enough of a threat to cancel a departure?

At my airline anything over 15 knots is a no go fwiw. I think everyone would agree your decision making was excellent.

 

[TWP]

I don’t want to be bumpin around in ANY GA aircraft with 20 knot shear. It’s just not worth it.

 

[Screaming_Emu]

Thanks. It's just always a bit embarrassing when local flight school's DA-40 takes off over your head as you're packing up. But the leadership of my flying club was very supportive.

As a pilot, I’m a lot more impressed by someone who has the cahones to stop the show than someone who could go up in those conditions and fly a perfect flight. Driving the plane is the easy part, it’s the decision making when the answer isn’t black and white.

 

[Screaming_Emu]

Heck I don't like a 20 knot sheer in the 777.

Winter time in Anchorage is JUST around the corner! Extra fun when you’re heavy and the low speed cues and overspeed tapes are really close together.

 

[Roger Roger]

Winter time in Anchorage is JUST around the corner! Extra fun when you’re heavy and the low speed cues and overspeed tapes are really close together.

Urghh the anchorage bowl gets gnarly AF

 

[Autothrust Blue]

As a pilot, I’m a lot more impressed by someone who has the cahones to stop the show than someone who could go up in those conditions and fly a perfect flight. Driving the plane is the easy part, it’s the decision making when the answer isn’t black and white.

Something something superior judgment superior skill etc.

 

[Screaming_Emu]

Something something superior judgment superior skill etc.

In this job, the judgement IS the skill.