For those who haven’t noticed the EASA PPL Syllabus contained in AMC.FCL.210A Exercise 15 includes:
(xix) Exercise 15: Advanced turning:
(A) steep turns (45 °), level and descending;
(B) stalling in the turn and recovery;
alioth wrote:
All other times, it’s all about control pressures.
There is something called aerobatics. Full deflections, neutral stick position (centered), timed deflections, deflections to obtain specific G forces and so on. I agree that normal flying is all about control pressures, at least if you want to fly smooth. But flying some aerobatics for sure increases your repertoire when it comes to making the aircraft do what you want it to do.
LeSving wrote:
I agree that normal flying is all about control pressures, at least if you want to fly smooth
Actually, for normal flying you need less inputs than one could imagine you start getting a feel of speed & power via ASI & RPM then later via stick & throttle force/position and once you know your aircraft very well: once wired in you head you only need air sound & engine noise to fly it, something very handy if you end up taking off with pitot tube cover ON and fail to notice/act on time…
But probably all of that goes to the bin once you get an IR, plug those Bose A20s with ANR, start taking pax, renting a new types, playing with SD/MFD, checking the plates and talking to ATC while on turn base to final 
Ibra wrote:
something very handy if you end up taking off with pitot tube cover ON and fail to notice/act on time
I did something similar once. The static inlets were covered due to a broken cover that someone had “fixed”. When I removed it, not all of it was removed, and I failed to notice the small piece left covering the static ports. While taxiing I didn’t notice anything. It was not before the speed reached normal climb speed that the ASI started to randomly wander all over the place (and I mean all over the place, from 0 to max and anything in between). I did a circuit and landed using the GPS as ASI. So much for theoretical musings about what happens if this or that is covered.
When thinking about it, I’m not entirely sure what I use at any given time, pressure, stick position, aircraft position, g forces, rates, noise, turbulence or whatever. It’s only in aerobatics I know for sure and have a thought process about it, but that may be because I am a novice at it, I don’t know. But I mean, a basic aileron roll is a standardized maneuver, and it’s done only one way for instance. Flying precisely, like towing gliders for instance, I tend to think of myself more as a perfectly tuned PID controller (which is impossible to explain to non engineering types, even though many non engineering types fly exactly the same way). Then the exact stick position or pressure or whatever becomes irrelevant. The deflections are just functions of the aircraft position, aircraft rates and intended path and speed, optimized to follow the “setpoints” and tuned to filter out turbulence. Once the glider is hooked off, it’s more a matter of getting down without over speeding, most of the time, and try to do a nice touch down. Stick pressure I guess ? but there is a fair amount of “PID” there as well.
I think it depends on the type of flying. I think it also depends on the aircraft. Stick pressure is better than position most of the time, but I see no reason to become hung up about it. After all, what it boils down to is to do what it takes to make the aircraft do what you want it to do. The exact way may be situational dependent.
LeSving wrote:
Flying precisely, like towing gliders for instance, I tend to think of myself more as a perfectly tuned PID controller
Believe it or not, but you do the same thing flying an instrument approach in IMC.
Airborne_Again wrote:
Believe it or not, but you do the same thing flying an instrument approach in IMC.
Very true, probably one of cases where I felt “pitch for glide slope” while I was told million times before to “pitch for speed”, when both modes are well wired I does not matter which one is true, tough you may argue that one is highly robust to variations if your goal is to see the runway where you want it, if you already see the runway then just ignore…
Andi wrote:
Or does the C172 suddenly become an uncontrollable monster in a turn stall that would make it dangerous and even grossly negligent to practice such at normal air work altitude?
Many if not all C-172 can be operated in the utility category and are certified for spinning. (need to check the POH for you aircraft and the PIC needs to be rated etc). The point being it will enter a spin if the entry is done correctly, a spin is not violent or stressful on the aircraft, but rate of yaw, roll, and pitch is greater than what the normal aircraft controls are capable off. Plus it is a dynamic condition where the roll, yaw and pitch will increase and decrease, periodically over several rotations, and the exact behaviour depends on the CG, and controls inputs. Its a very high drag condition and the airspeed will stabilise in a range of 50-70kts if my memory is correct.
Part of spin testing is to ensure that this dynamic condition can be recovered.
The recovery from the spin CAN be stressful on the aircraft especially if the flaps are extended. I have only done intentional spinning with C-172 with a forward cg (utility category) lightly loaded student and instructor, flaps retracted etc. It needs positive control inputs to enter a full spin, from memory in this configuration the ailerons are still quite effective in the stall. With high power, flaps extended, and rear CG the entry to a spin (incipient phase) often doesn’t need anything more than the stall itself. (I have not done full spins in this configuration).
However I think there are better aircraft to explore spins and this phase of flight, and aerobatics is not for everyone. What really matters is the identification of the problem, i.e. approaching and or entering the stall, and application of the correct corrective control inputs, the sooner the better.
http://www.tc.faa.gov/its/worldpac/techrpt/rd77-26.pdf
This important FAA study of the 1970’s led to changes in instructional technique and emphasis.
In the period 1967-1969 of the 1,261 stall spin accidents, 19% were in the instructional phase (p.6). This is higher than the % hours of instructional flight overall.
The Cessna leading edge cuff modification (Cessna 172 M onwards), and the Warrior taper wing design (adopted in the Archer and Arrow III) helped make stall spin characteristics even more benign, especially in the case of the Warrior.
Achieving stable autorotation in a 172 is not easy, the anti spin effect of wing washout, where the angle of attack is less in the outer wing than in the wing roots, is quite effective in resisting autorotation.
Some types, the Tomahawk for example, continued to experience stall/spin accidents during instructional flight, while I believe the Warrior has never suffered a stall/spin fatality.
This question has arised may time among pilots in my aeroclub in Spain.
Due to my military flight training, I was teached and evaluated on how to stall the aircraft with and without power, levelled, on final and on base leg (most critical). We performed that at a height so we had enough altitude to recover. We let the aircraft go into a deep stall, well beyond buffeting so we could see the aircraft going from 45 to almost 90 degrees of bank in a second while descending.
For the recover, we applied full power while rolling out so we could reduced the AOA allowing the aircraft to fly again. I remember the F-5 being specifically critical on this manoeuvre but it was necessary to learn it since you could see yourself in that situation quite often if you pulled too hard on base.
During my first assignment I was based in a shared airport as a FJ instructor and we had an ATPL flight school next door. During one of the civ/mil bbqs we used to have, this particular topic arised and I was VERY surprised that during their commercial training, not a single day they stalled the airplane. They only performed levelled stalls with and without power and when hearing the stall warning they would recover! They didn’t know about the buffeting or what is like fly/recover an aircraft that is stalling.
Another big important mistake, specially when talking with non-professional pilots is how does an aircraft stall. Roughly 80% of the pilots at your local club will say that is because of lack of speed. FALSE: the aircraft stalls because of an excess of AOA (see any lift chart for reference). Both are related, that is true, but the aircraft stalls because AOA.
And you know what? I’ve seen many mishaps during: “Oh there is my house, let’s circle it. My stall speed is 50kts, I am at 60kts so I’m ok.” FALSE. If you continue circling at 60kts at let’s say 45º of bank, if you don’t want to loose altitude, you are going to have to pull →increasing your AOA and then stalling your aircraft because that speed of 50kts was calculated for a wings levelled situation.
Regards
speed wrote:
Due to my military flight training, I was teached and evaluated on how to stall the aircraft with and without power, levelled, on final and on base leg (most critical). We performed that at a height so we had enough altitude to recover. We let the aircraft go into a deep stall, well beyond buffeting so we could see the aircraft going from 45 to almost 90 degrees of bank in a second while descending.
For the recover, we applied full power while rolling out so we could reduced the AOA allowing the aircraft to fly again. I remember the F-5 being specifically critical on this manoeuvre but it was necessary to learn it since you could see yourself in that situation quite often if you pulled too hard on base.
There are reasons for differences in basic flight training between ATPL and the military. For one thing, in an F-5 you can eject. Also, the manoeuvres you normally do in civilian flying is quite different from what is done in military flying.
