Originally Posted by
PearlPilot
Very interesting stuff. Gets into some advanced aerodynamics and you'd better know what you are doing. There are a couple of jump operations closer to where I operate out of and since we are located in a TSRA area I doubt they use techniques such as this to get down.
On a similar note, please forgive me if the said note is dissimilar to what we are discussing here. I was giving a photo flight and the gentleman (who was an Air Force pilot) wanted to take a "vertical shot" of the target since the gear of the Skyhawk would be in the way. We were at 1,000 foot AGL surrounded by mountainous terrain and he wanted me to "try doing a crab" for which I scratched my head. I have received adequate spin training and I was not about to "crab" or be uncoordinated at 1,000 ft. AGL so I refused such a maneuver and settled for a 45 degree bank. I actually climbed to 2,000 AGL and made a descending 45 degree bank to 1,000 ft. AGL. If I would have tried to crab or be uncoordinated in the name of getting the landing gear out of the way, I think I would have found a very fast way to get down indeed.
I assume he meant "sideslip" rather than crab.
Sideslips/forward-slips (same thing, just differences in the relative wind direction and path along the ground) are used by all sorts of GA aircraft
all the time to land! Many people teach this as a technique to get better visibility of the ground, but I never went crazy with it, as being uncoordinated is usually not the best thing for passengers and you need to pay attention to maneuvering speeds when making control deflections obviously. Still, I would have my students do it at times. Don't let your speed drop excessively low, but realize that sideslips and forward-slips are done all the time close to the ground. Remember that a spin requires a yawing moment, if you aren't yawing when you stall, it will not really start to spin (unless the stall then causes a strong yaw, but this can usually be managed). Use good judgement, don't let your speed get dangerously low, but it can and is done safely all the time. You might not be able to maintain altitude for long while doing this, so it's best to limit it for a while, climb back up, repeat if necessary. Obviously each aircraft is different and not all will react the same, but you can do this all day in standard cessna single engine, and while I may not want to stall in some other aircraft while being "uncoordinated", the airspeed and any POH/AFM limitations are really key here. I've had people come to me and say they were never taught to do full forward-slips to landing in that airplane with full flaps, and while a tail-oscillation buffet is possible (it's been very rare for me), it does not result in loss of control and as long as you got fuel in both tanks, you can do this all day too, not restricted in the manual or anything.
On the other hand, flying low over mountainous terrain is something that has to be managed correctly. There are things you can get away with, and then the right way to do things. If you didn't feel comfortable getting low/not having an exit, then more power to you.