The basic stall of the last three lessons was flown wings-level, power off, on a clean dry wing. This lesson removes those comforts one at a time: power on, turning flight, swept wings with T-tails, ice, tropical rain, and finally the stall that starts rotating, the spin. Each variation changes what the stall looks like, how much warning precedes it, and in the worst cases whether recovery is possible at all. It is the module's longest lesson because it is where the exam's scenario questions live.
Power-off and power-on stalls
Add power to a stall and three things change. First, the stall comes slower and steeper: the stall-speed lesson's thrust component and slipstream effects lower the stalling speed, so the aircraft arrives at the stall at a lower speed and a markedly higher nose attitude. Second, on a propeller aircraft the stall breaks more sharply and more asymmetrically: the slipstream keeps the inner wing sections flying while torque and the spiralling slipstream load the two wings unevenly, so one wing tends to drop hard at the break, and with the aircraft already nose-high and slow, those are exactly the entry conditions for the spin at the end of this lesson. Third, the elevator and rudder, bathed in slipstream, stay deceptively effective right up to the break. The recovery is the standard one (angle of attack first) with one adjustment each way: power-off, thrust must be added during the recovery; power-on, it is already there, and the pitch-down needs to be positive against the higher attitude and the strong nose-up trim state.
Stalls in climbing and descending turns
In a turning stall, the two wings do not meet the air at the same angle, and which wing stalls first follows from the geometry of the helix each wing flies:
Climbing turn — both wings climb at the same rate, but the outer wing travels faster along its wider circle: its path through the air is shallower, its relative airflow arrives less steeply from above, and it therefore flies at the higher angle of attack: the outer wing stalls first, and as it drops the aircraft rolls toward the outside: OUT of the turn, the bank shallowing or even reversing. (Before the stall the same faster outer wing makes MORE lift and over-banks the turn; at the stall that logic flips.)
Descending turn — the argument mirrors: the slower inner wing descends on the steepest helix, meets the airflow rising most steeply from below, flies at the higher angle of attack, and stalls first: the aircraft rolls INTO the turn, steepening the spiral.
Recovery is unchanged in essence (reduce the angle of attack first, then level the wings) but the entry attitude means the roll-off must be expected and met without instinctive opposite aileron.
Pitch-up, the T-tail, and the deep stall
Now assemble the most dangerous combination in the module. The previous lesson's swept wing stalls at its aft-sitting tips and pitches nose-UP at the stall: driving itself to a still higher angle of attack. On a T-tail aircraft the same moment has a second act: as the angle of attack grows, the broad turbulent wake of the stalled wing rises relative to the aircraft, and sweeps across the tailplane mounted high on the fin. The elevator, the one control that could push the nose back down, is suddenly working in slow, chaotic, low-energy air; its authority collapses just as the pitch-up demands more of it. And as the wake reaches the tailplane, the downwash inside it drives the tail's angle of attack more negative (more download, more nose-up), adding to the pitch-up even before the elevator's authority is gone.
Carried far enough, the aircraft settles into the super stall, or deep stall: a stable, locked-in stalled condition at a very high angle of attack, the aircraft roughly level in attitude but descending very fast along a steep path, the wing fully stalled, and the elevator drowned in the wing's wake with no pitch authority left to lower the nose. The stability is the danger: the aircraft does not tend to drop its nose and fly out; it tends to stay. Recovery from an established deep stall may be impossible by any control input, which is why the certification answer is not a recovery technique at all.