Crosswind landings
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Warlock
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Warlock
Best live TV was watching LHR landings today with the storm in England…watching heavies at 120 knots at 4000 ft on final with crosswind guys of who knows…lots of go rounds but som great pilot skills as well… That Buff pilot has it as well…
Sac Arrow
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Snorting his way across the USA
Castering main gear! That's cheating!
Mxfarm
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slipping not a option
kaiser
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The pilot formerly known as Cool Beard Guy
Larry in TN
En-Route
I've landed with winds gusting over 50 kts a few times. It's a lot of work.
Always striking how smooth the runway seems after enduring the ride on the approach.
Always striking how smooth the runway seems after enduring the ride on the approach.
Zeldman
Touchdown! Greaser!
Why is it when I watch that landing and keep hearing this.??
JuggyJet
Pre-takeoff checklist
My two worsts were at KSFO 19L after the Pacific crossing years ago. Flying the “swinging arc” over the runway to de-crab in a 747 was quite interesting indeed. I kept a cool face in front of the crew as I cleared the runway (I wonder if they noticed my shaking knees).
Tobias Göller
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SCNR
50KTS? That's higher than many GA-Planes (at least: Piston Planes) stall speed...
I remember seing someone try to land a shock cub in wind conditions that were close to his stall speed... After several attempts he aborted and landed somewhere else.
Just out of curiosity: Do you still use Vapproach + Gust-Speed/3 for the approach speed in those conditions?
midlifeflyer
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The SportCruiser LSA actually has a published maximum demonstrated headwind component. Published Vso is 31. Max demo headwind is 24.
Tobias Göller
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Demonstrated... so it's not a real limit (but you should still think about what you're doing). In the end: All planes do have a headwind component... it's called VS(0)
I once almost flew backwards in a C152 on approach (G/S of ~5kts).... not a very good feeling, to be honest. Was one of my shortest landings ever
midlifeflyer
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The crosswind component in most airplanes is also not a real limit either, just informational.Demonstrated... so it's not a real limit (but you should still think about what you're doing). In the end: All planes do have a headwind component... it's called VS(0)
I once almost flew backwards in a C152 on approach (G/S of ~5kts).... not a very good feeling, to be honest. Was one of my shortest landings ever
But I wouldn't call published Vso a headwind component either. Published Vso is at max gross weight and I don't know too many pilots who recalculate it for typical lower weights. I think that's at least part of the reason why the SportCruiser lists it 6 KIAS below Vso - to provide a buffer for avoiding landing backwards.
PaulS
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That's pretty crazy. I've never thought about a backward landing, but it's definitely possible and would probably result in a disaster.
midlifeflyer
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I haven't seen it elsewhere but I suspect SportCruiser includes it because of the number of people who transition to one from airplanes with much higher stall speeds. Plus, the POH recommended final approach speed is 60-65 KIAS, a good 15-20 KIAS faster than 1.3 Vref so it might create a false sense of security.
Larry in TN
En-Route
It wasn't in GA airplanes. DC9, DC8, 767, and 737.
Target speed for the final approach is Vref plus half the steady-state headwind component plus all of the gust. Minimum additive is 5kts and max is 20kts (15kts on the 737).
Tobias Göller
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Thanks!
midlifeflyer
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I've always been curious about that one. Is it based on the assumption that it will not remain "steady state"? Some other aerodynamic reason? Or something unrelated to flight characteristics?
Larry in TN
En-Route
I don't know. But, don't break out the micrometer. It's just a system to add some extra margin in windy, and gusty, conditions. It's not a precise scientific calculation.
FastEddieB
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Fast Eddie B
Surface friction usually causes a drop-off of wind as you come into ground effect. Most of us have seen this in approaching with a crosswind which largely goes away in the flare. So it's not hard to imagine that a strong headwind may largely vanish close to the ground - think wind shear - which could easily result in a stall way before the pilot is ready for it. At least that's my thinking.
midlifeflyer
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I guess I wasn't clear. I'm not breaking out a micrometer or looking for a precise calculation. Nor am I talking about gust factors. I was just wondering about the reason for any adjustment for a steady state wind of any type.
Timbeck2
Final Approach
Brings back some good memories. I was stationed at RAF Fairford in '93-'94.
midlifeflyer
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One of my favorite things to watch is a pilot who thinks the goal of a crosswind landing is to touch down on one main touching down on one wheel when the crosswind went away. And yes, wind shear can cause a problem, especially with larger aircraft which have difficulty changing momentum. That's the reason we add a gust factor. That what made me wonder - is there something about this particular airplane that requires a BIG margin?
The impression I got from the post was different adding to Vref for any headwind in addition to accounting for gusts/shear.
To put numbers on it. We have winds straight down the runway reported as 15G25. With a Vref of 70, I would add 0 for the 15 and 5 (1/2 the gust factor), giving me a 75 KIAS approach speed. In that airplane @Larry in TN would add 7-8 for the 15 and another 10 for the gust factor, for a approach speed of 87-88 KIAS for an airplane with a 70 KIAS Vref.
Albany Tom
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Limiting factor on landing a cub is being able to taxi it after you've landed it. The landing part is easy by comparison. And there's absolutely a crosswind limitation, you need to have enough rudder to get the ground track close enough before touchdown, or you're going to have a problem. But at that point you can probably land diagonal or even across the runway if you really had to.
For a tricycle plane, I think the math is a bit different. Not only does the airspeed drop off close to the ground (for anything) as FastEddie mentions, but your AOA is going to drop when the nose comes down. That helps a lot keeping it from flying again. "land o matic" I believe they called it.
No way would I try landing a plane backwards, though. With RC planes, I would fly in winds well above stall speed. But you don't land them backwards, mostly because they really don't handle very well on the ground that way. Instead, you "hover" the plane into the wind, making ground speed = 0, and then just fly it down. "Push" it down is how it feels. Then, you walk out and go get the plane, because there's no way you're taxiing it. If you move it, the wind will pick up the wing and toss it through the air like a kite. Using that technique, you can land a light RC plane at something close to it's max cruise speed. Works best if the wind is at your back, and you're landing toward you, because you want to minimize any crosswind flight. Tall grass helps, keeps things from sliding around. This is for lightweight/small models, not expensive stuff. Flying RC in the wind is great fun.
For a tricycle plane, I think the math is a bit different. Not only does the airspeed drop off close to the ground (for anything) as FastEddie mentions, but your AOA is going to drop when the nose comes down. That helps a lot keeping it from flying again.
"land o matic" I believe they called it.No way would I try landing a plane backwards, though. With RC planes, I would fly in winds well above stall speed. But you don't land them backwards, mostly because they really don't handle very well on the ground that way. Instead, you "hover" the plane into the wind, making ground speed = 0, and then just fly it down. "Push" it down is how it feels. Then, you walk out and go get the plane, because there's no way you're taxiing it. If you move it, the wind will pick up the wing and toss it through the air like a kite. Using that technique, you can land a light RC plane at something close to it's max cruise speed. Works best if the wind is at your back, and you're landing toward you, because you want to minimize any crosswind flight. Tall grass helps, keeps things from sliding around. This is for lightweight/small models, not expensive stuff. Flying RC in the wind is great fun.
dmspilot
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Pretty sure I fly a different airplane than Larry. The formula we use is identical.
The wind is never steady. A gust is defined, for the purpose of METAR reporting, as "rapid fluctuations in wind speed with a variation of 10 knots or more". A large airplane has much more inertia and is more more sensitive to gusts, in addition to the fact that turbine engines have a long lag time due to spool-up. The buffer is necessary. Even then, most of the pilots I fly with will maintain at least 5 knots above the bugged approach speed, since we are required to maintain that -5/+10 (used to be -0/+10 before a change in our manual).
Zeldman
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If the wind ain't blowin' then I ain't goin'...
Larry in TN
En-Route
OK. I see.
There's no guarantee that a steady-state wind will continue blowing steadily. Half the headwind component gives you some margin for changes and the turbulence that strong winds will almost always produce. Adding the full gust factor is because the full gust can, and does, go away because it is a gust.
My record in the 737 is a target speed (big speed) of 165kts. That was a Vref of 145 plus what was then the full 20 knot additive. Since then, Boeing has capped the 737's additive at +15kts due to the Vref already being a bit on the high side for tailstrike protection.
And, as always, I prefer strong, gusty crosswinds for my landings. I find they lower expectations.
midlifeflyer
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Ah... that's what I was thinking. Thanks.
Salty
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On days like that I would make multiple flights without turning. takeoff at full throttle, slow down and drift backward down the runway, land in a hover, rinse and repeat.Limiting factor on landing a cub is being able to taxi it after you've landed it. The landing part is easy by comparison. And there's absolutely a crosswind limitation, you need to have enough rudder to get the ground track close enough before touchdown, or you're going to have a problem. But at that point you can probably land diagonal or even across the runway if you really had to.
For a tricycle plane, I think the math is a bit different. Not only does the airspeed drop off close to the ground (for anything) as FastEddie mentions, but your AOA is going to drop when the nose comes down. That helps a lot keeping it from flying again.
No way would I try landing a plane backwards, though. With RC planes, I would fly in winds well above stall speed. But you don't land them backwards, mostly because they really don't handle very well on the ground that way. Instead, you "hover" the plane into the wind, making ground speed = 0, and then just fly it down. "Push" it down is how it feels. Then, you walk out and go get the plane, because there's no way you're taxiing it. If you move it, the wind will pick up the wing and toss it through the air like a kite. Using that technique, you can land a light RC plane at something close to it's max cruise speed. Works best if the wind is at your back, and you're landing toward you, because you want to minimize any crosswind flight. Tall grass helps, keeps things from sliding around. This is for lightweight/small models, not expensive stuff. Flying RC in the wind is great fun.
Tarheelpilot
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The underlying idea is to keep the aircraft inertia up at a safe level. If the winds shear off you’re still flying. In the absence of maintaining the inertia a shear could put you short of the runway.
midlifeflyer
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Often a limiting factor with tricycles too. We were in St Francis, KS for their (then?) annual Stearman fly-in. As usual, we stayed overnight. Very windy overnight. "Calmed down" to the 22G32 range in the morning, No problem for takeoff. One of the 3 grass runways was pretty much directly into the wind, but taxing to it in the 172 we flew was going to be a challenge.
We were tied down into the wind. Straining against the ropes. My wife asked, "is this safe?" I answered, "we'll untie, start up and turn. If I don't like it, we'll turn back and shut down."
Taxi was, well, interesting. Takeoff was the shortest I've ever done
Albany Tom
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We flew out of a grass field that was a park. I couldn't do the roll back, but would fly without turning all the time, a bit like flying a kite. Once in a while someone would walk up and ask if the model was "stuck" in the air. Great fun.