In a previous question, Mongo described flying his Cessna with a negative ground speed in a head wind. In this situation, what is the correct thing for a pilot to do, if there is nowhere to land downwind and upwind ground speed is negative? Other answers on that page show that, for very light aircraft, descending will not always get you to a low enough wind speed that you can fly forwards.
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asked Jul 10, 2019 at 12:21
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$\begingroup$ "correct" has no meaning in this situation. And it would be a very contrived situation for there to truly be no possible landing place anywhere downwind. Oh well, at least the crash will occur at a low groundspeed. $\endgroup$– quiet flyerCommented Jul 10, 2019 at 12:25
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2$\begingroup$ @quietflyer I reworded a bit. It's not unusual for downwind to be ocean. $\endgroup$– Anonymous PhysicistCommented Jul 10, 2019 at 12:37
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$\begingroup$ Seems to me the question could be asking about anything from how to predict whether surface winds will increase or decrease, to who to talk to on the radio for advice,to how to maximize endurance while waiting for wind to change, to how to execute a forced landing in adverse conditions-- too broad. Also, to me " correct" implies the right answer to a test or an action that is required by some regulation which doesn't really seem to apply here. $\endgroup$– quiet flyerCommented Jul 10, 2019 at 12:54
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$\begingroup$ I would substitute "best" for "correct" but it still seems to me that the question would still be too broad. Maybe others will feel differently and provide useful answers. $\endgroup$– quiet flyerCommented Jul 10, 2019 at 13:38
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3 Answers
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Before even taking off, a pilot is required to get a weather briefing, including winds. Wind speeds are usually predictable and well known. If a pilot was flying against strong headwinds, with no good landing alternate, he screwed up his flight planning before he even started the engine. A headwind doesn't even have to be strong enough for negative GS, just strong enough to cause concern.
Winds vary by altitude in both strength and direction. If a pilot does find himself in such a situation, changing altitude by a few thousand feet, higher or lower, can very likely change both the wind direction and speed to something that is manageable.
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10$\begingroup$ This is one of the rare situations where the right answer is "don't have that problem." This can happen with mountain pass winds, and is one of the reasons mountain flying is so hazardous. $\endgroup$ Commented Jul 10, 2019 at 15:54
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This question is actually applicable to a power off emergency gliding situation, where your best option may be behind you.
The way the question is worded (and one of the reasons light GA air craft are generally designed with one wing and a bit more speed than old time Jennys) is that progress upwind will drain your energy source (be it altitude or fuel) much faster than downwind (note going downwind does not necessarily mean LANDING downwind).
Nor is this question in the realm of the impossible, as I once witnessed a light GA (152 or 172) on final inching into a 35 knot headwind in Armarillo, Texas one fine day (windmills are doing great out there).
So, going upwind is out. On your way upwind, always try to pick out possible landing sites like open fields or interstate highways. If there is no where to land from where you came from, that would be a poor trip plan.
Changing altitude may be an option, though going lower may be more turbulent. Abort ASAP if weather is marginal.
answered Jul 11, 2019 at 17:54
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If you are flying into a headwind, that means that there is an area of High pressure to your right. Frequently, as you leave move further away from the low pressure area, the winds will diminish. This isn't always the case, but it is the PICs responsibility to check weather conditions along the route and the routes to any alternate destinations.
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$\begingroup$ oops. that was a typo. The High would be on your left $\endgroup$ Commented Jul 16, 2019 at 23:40
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$\begingroup$ Aren't winds weakest in the middle of a low or in a middle of a high, and strongest some distance away from the middle of each? I'm not sure this answer is really right, or at least I think there could be some cases where going toward the high might bring you closer to the zone of strong winds between the low and the high. Maybe though the answer has more truth as a general rule of thumb than I'm realizing. $\endgroup$ Commented Jul 16, 2019 at 23:41
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$\begingroup$ Anyway, it's certainly more "outside the box" than some of the other answers which is nice. $\endgroup$ Commented Jul 16, 2019 at 23:41
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$\begingroup$ You can easily fix that typo and then delete the related comment; welcome to ASE. $\endgroup$ Commented Jul 16, 2019 at 23:42
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1$\begingroup$ Welcome to aviation.SE! You might also want to mention that the direction of the high pressure area depends on which hemisphere you're in. Not everyone is in the northern hemisphere :-) $\endgroup$– PondlifeCommented Jul 17, 2019 at 0:04