The back side of the curve.
The region of reversed command is where flying slower paradoxically needs more power. The whole curve shifts up with density altitude — get yours from the density altitude calculator — so high, hot fields shrink your margins.
Parasite drag increases with the square of speed, while lift-induced drag is higher at lower speed. The bottom of the curve is the L/Dmax speed. Flying at very slow speeds requires high angle of attack (AoA, or alpha), so it takes more power to fly slower — the region of reversed command. Inside this region, altitude is controlled with power and airspeed with pitch. Drag the speed across the chart and watch the power change. ↑ use the density altitude from above
Educational estimates only — not for flight planning, dispatch, or weight-and-balance. Always fly the numbers in your POH and current official weather.
The range of slow airspeeds, below the minimum-power speed, where flying slower needs more power, not less. It's the back side of the power curve: slow flight, short-field approaches, the initial climb. Slow down here and induced drag rises, so you need more power just to hold altitude.
The slow-speed part of the power-required curve, left of its lowest point (the minimum-power speed). On the front side faster needs more power; on the back side slower needs more power. Dragging it in low and slow on a short-field approach is a classic factor in undershoot and stall-spin accidents.
It shifts everything against you: power available falls as the air thins while the power required (in true airspeed) stays about the same. The gap between them, your excess power for climb and maneuvering, shrinks, so your margins are thinnest exactly when high, hot fields demand the most. Get yours from the density altitude calculator.