Let's say you're flying a light plane, and you fly up into a canyon at 8000 feet. At 8000 feet, your turning radius is perhaps 600 feet. The canyon is 1000 feet wide. You'd like to turn and get out of the canyon, but there's no room to turn. And the canyon floor is rising too fast for you to climb out. Are you dead?
Maybe not. I have been studying this for several years. Our good friends lost their daughter in a flying accident in a box canyon, just like that, about 10 years ago. She and another student pilot died in the crash, along with the certified flight instructor. I still cry about that. A lot. Especially today. How can you get out of this trap?
(a) Put down your flaps to 10° or 15° (or maybe 20°) to increase lift and drag. Apply full throttle. Do not let speed build up. Do not let your altitude above the canyon floor get small. Turning radius may be 600 feet at full speed, but it may be smaller under those conditions. You can turn a lot better. Flaps and power help you maintain control and avoid stalling. Maintaining some altitude above the ground can be extremely important in view of (c).
(b) Get way over to the right of the canyon, maybe 40 feet from the wall. I say to the right, because the flight instructor (or pilot in charge) on the left should be in charge of these fairly dangerous maneuvers. He has to use his best judgment. His feel for what the plane is doing is very important.
When he cocks the ailerons and pulls back on the yoke, it may be very close to a stall. You gotta have a feel for that. It's also true that the engine's torque may help you turn left better than right. (If the canyon is deepest on the right, okay, get over to the left. Or if you know there is a crosswind from the right, turn toward it.)
(c) Make your turn early, make a hard turn, and let the plane descend. Use the plane's lift to pull you around in the tightest possible safe turn that you can do without stalling. If you tried to hold altitude, you will probably stall and crash. But if you let the plane descend to the left, you have a better chance. That's assuming you are somewhat above the canyon floor.
(d) Do not fly up into canyons. Never. If you want to check out a canyon, always come in from above and descend—assuming the canyon does not have excessive sharp turns or narrows (of which there may be many).
(e) Under conditions of full power but lowered flaps, you may be flying at 55 or 45 mph depending on the headwinds. So even if planes aren't exactly as bust-proof as cars, you have some chances of surviving a 50-mph crash. Not so at 85 mph. The flaps may get you around the corner. There's no guarantee, but that's what I would bet on. Better odds—and a better chance for a good pilot's skill to help. Of course, a really good pilot would never get you in that bind in the first place. A cat will not crawl into a hole where his whiskers scratch the walls.
(f) If you live in flat country, you may never have to worry about this. But if you live near mountains, you would definitely want to practice this at a safe altitude, out in the open, so if you stall, you have a lot of air under you to recover. You may not be able to judge how much space this maneuver takes, but you can get a feel for how the plane feels and handles.
(g) If you were in a very narrow canyon, maybe 200 feet wide, you could zoom up, cut speed, apply some flaps, do a half-roll, cut power way back, and finish your half-loop. But this is not legal for most light planes, and it might cause excessive G's or speed. It still might save your life—if you were 600 feet or more above the canyon floor.
Do not fly directly toward a high mountain pass trying to get across. If you have a large altitude margin, you might do that. But if you aren't sure, don't try to fly toward the pass.
Circle around on the right. If your altitude is okay, then you could fly up to the pass and go ahead and veer right across the pass. But if you are kind of skeptical, and you think there may be downdrafts, or if you aren't sure there will be enough updraft, veer left and go around again. Try to get a little higher and burn off a couple gallons. You may have much better luck on the next try.
Too many pilots have failed and crashed because they were confident they could get over a pass. But downdrafts can be very nasty and can be the downfall of "confident" pilots. The Alaskan bush pilots who are alive today have learned from such advice.