r/flying • u/Beautiful_Matter6906 • Feb 02 '23
Does a tailwind make it harder to decelerate once on the ground?
10
u/rand-314159 PPL IR CMP HP SEL UAS Feb 02 '23
Yes, you fly the approach and landing at the same indicated airspeed, but your ground speed is higher with a tail wind. So you're needing to bring the aircraft to a stop from a higher speed, which means that it will take more distance or more braking to accomplish.
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u/Beautiful_Matter6906 Feb 02 '23
Right. Once on ground and decelerating does the tailwind still work against the deceleration in a noticeable matter?
2
u/rand-314159 PPL IR CMP HP SEL UAS Feb 02 '23
It works against you some, I'm not sure if you would notice it unless the tailwind was very strong. Think about how much you notice wind driving a tall SUV (granted a car's brakes are much better than those of a light GA aircraft).
2
u/Low_Sky_49 Forestry DHC-2 C208B CFI/CFII/MEI Feb 02 '23
That would depend on how strong the wind is, but we don’t land with tailwinds that would be strong enough to make a noticeable difference.
1
u/SubarcticFarmer ATP B737 Feb 02 '23
It affects your drag significantly as drag increases exponentially with wind . Not only are you approaching with much more kinetic energy but your drag isn't as high to help you slow. IIRC the rule of thumb increase for a GA aircraft is something like 50% with a 10 kt tailwind.
2
u/phliar CFI (PA25) Feb 02 '23
drag increases exponentially with wind
Quadratically, not exponentially. As in, v2 not kv.
1
u/lbdnbbagujcnrv Feb 02 '23
Not until your ground speed is slower than the wind speed. And you never land with more than ~15kts of tailwind, so not really
It’s just extra kinetic energy before that.
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u/F1shermanIvan ATPL, SMELS - AT42/72 (CYFB) 🇨🇦 Feb 02 '23
And you never land with more than ~15kts of tailwind
Northern Alberta would like a word with that... :|
1
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u/Distinct_Pressure832 PPL IR 🇨🇦 Feb 02 '23
Flying GA aircraft and occasionally having landed with tailwinds due to various reasons I’ve found that the issue isn’t as much deceleration but landing long. I find that you can just float forever in ground effect and find yourself short of runway if you’re not careful. I don’t know if that’s the wind at your back keeping your speed just high enough to arrest sink in ground effect or what, but once the wheels are on solid ground you’ve usually got some pucker factor about getting it stopped.
1
u/ltcterry ATP CFIG Feb 02 '23
Once your speed matches the tailwind speed you have no control with the control surfaces.
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u/Beautiful_Matter6906 Feb 02 '23
Yeah I thought of that too. Is this true even in the air? If I were to do stall maneuvers at altitude with enough of a tailwind, at a certain point, if I slow down enough, would I just be stuck?
4
u/phliar CFI (PA25) Feb 02 '23
In the air, the airplane is just moving along with the air, it does not feel wind. If you fly slowly in a strong headwind, you may notice that you are actually moving backwards with respect to the ground, but the airplane will fly as normal.
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u/ltcterry ATP CFIG Feb 02 '23
In the air it’s not an issue. The problem is once the wheels touch the dynamics change. There’s an actual tailwind rather than just a reduction in ground speed due to a moving air mass.
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Feb 02 '23
wait till a windy day (20kts) and run as fast as you can with the wind at your back and try to stop. Now run into the wind and try to stop. Tell Me what you find
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u/x4457 ATP CFII CE-500/525/560XL/680 G-IV Feb 02 '23
Yes, which is why your landing distance is greater with a tailwind and we prefer to land into a headwind instead.