Saturday 25 May 2013 00:15 UTC
This forum is for anything to do with light aviation
flying into an aerodrome that's unmanned, runway is 09/27 wind is 360/15 I'm in a 172 2pob and nobody else in the circuit.
Which runway do I use!
I'm having this debate and I need confirmation.
Any noise sensitive areas about? Is the wind at ground level or higher? If it's higher and you're in the N Hemisphere it will back as you near the ground. Where's the sun? If it's low and sat on the end of the runway judging the flare can be tricky. If you're flying from the left seat, it's easier to slip to the left if you have to scrub off excess height. Easier to do that if the wind's from your right, as the nose will already be pointing to the right of centre line.
I'm sure there are lots more things to consider when making your decision, which is probably best done at the time rather than hypothetically, in advance.
Lucky in life, unlucky in computery stuff.
Hypothetical is important preparation for circumstances not yet experienced.
By simulating such things in our minds we prepare ourselves to solve problems in advance.
When the engine went bang in the Jungmann, it was no surprise, and so I just got on with the job as I'd already considered the possibility beforehand, not specifically for this aeroplane but just generally.
I was in the back seat of a Cessna 172 once going into Headcorn. (Bad idea that back seat!).
Following the railway eastbound I watched the cloud shadows doing likewise (wind from west).
At Headcorn the wind was 8 knots and dead across the runway but I reason that above ground the wind was from the west and any gusts would come from that direction.
He was given 11, I suggested the pilot ask for 29, and to join downwind for that runway rather than straight in for 11.
We overshot 11 easily... There's little point in trying to get down with a good tailwind!
Dumb-bell turn and onto 29... The wind sock still from the south, but the approach into the wind was better... We still went around as 8 knots was too much crosswind... Back to Biggin Hill.
Not a terribly enjoyable flight, and later, the way he handled the CuNim over Biggin and moving eastwards was not good either.
So the point is that with a ninety degree crosswind on the ground, you need to know what the wind is higher up, and perhaps whether the wind backs or veers with increased altitude....
In BC wondering wandering
As others say, there are bound to be other factors. I can think of:
High terrain, go-around route, noise sensitive areas, sun glare, taxi route etc.
If all is equal, I'd choose 27 so you crab to the right, giving you (in the left) a clear view of the runway.
(Unless you land off a co-ordinated turn...!)
More or less in priority order:
(1) Neither, if your personal crosswind limit is 14 knots.
(2) Whatever the signal square says.
(3) Whatever the AIP or Pooley's entry or website says.
(4) All else being equal, whichever gives you fewer minutes of rental to pay for.
The runway I operate from is often subject to crosswinds of that order. One end has no obstructions and the other has trees and buildings on the approach which generate sink and rotor in certain crosswind conditions. In such cases it is common practice to land and takeoff via the unobstructed end unless tailwind component is uncomfortable.
I guess that a flight guide entry should give a clue as to best practice at that strip or, the PPR call gives an opportunity to ask.
Engurlish levul 6 profishent
I can't understand why this is a conundrum. Don't we all know that in aviation when a decision has to be made, we must attempt to make the least worst decision. If there are two possibilities which are equally least worst, just pick one of them and then make the best of it. Definitely the worst option is making no decision at all, until the arrival of the ground makes it for you.
In the scenario given, assuming the upper wind is the same direction as the windsock and there are no curlover differences between the ends, I'd fly the opposite handed circuit from the last time I landed, to keep in practice. I want my base leg into wind, so that tells me which end to land at.
Is it possible for the wind on the ground to be the same as at 1000'? Shirley the friction and coriolis will make it decrease in strength and back in direction (in N Hemis)?
Professor, why do you specifically want your base into wind? I realise things will be slowed down (relative to the ground), but is that necessarily a good thing? One would have to delay powering down and starting the descent, and would then become more susceptible to an engine failure, needing it for that bit longer. And I reitterate my earlier comment about wind from the right making it easier to slip to the left and keep the runway nicely in view - that could be compromised by your into-wind base (depending on circuit direction).
Although I agree it is good to think about possible scenarios in advance, my earlier comment was by way of a taking care not to get too fixated on any particular solution to any particular problem. The real world situation one finds oneself in may not be, or remain, as one had so carefully thought through on the ground, at leisure. Better methinks to have some general questions and answers in mind when approaching whatever runway/wind/most other problems one faces, and make the best decision possible using those self-briefing principles. I believe there is always an inherent risk in trying to make a "problem" fit a particular solution. Better to do it the other way round, IMHO.
Lucky in life, unlucky in computery stuff.
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