Common errors

Slow flight errors split into three families: airspeed-band errors (not slow enough, or accidentally stalling), altitude errors (the back-side power-vs-altitude relationship), and coordination errors (rudder management at high AoA). The seven below cover the common faults.

1. Not slow enough — airspeed above the band

What it looks like: the airplane is flying at, say, 70 KIAS with full flaps. Stall warning isn't activating. The airplane is in approach configuration but not in slow flight.

Why: the pilot reduced power but didn't pitch up enough to bleed airspeed to the minimum-controllable band, or held a normal-approach airspeed instead of the slow-flight airspeed.

Fix: pitch up progressively while reducing power, until the stall warning just begins to chirp. That's the slow-flight target — sustained operation at that airspeed.

2. Too slow — sustained stall warning or stall

What it looks like: the stall warning is on continuously, or the airplane buffets / stalls and recovers below the maneuver altitude.

Why: over-corrected from #1 — pitched up too far, or didn't recognize the stall warning as the lower limit.

Fix: back off pitch slightly to silence the continuous stall warning. The target is intermittent or just-on stall warning, not continuous. If the airplane stalls, recover (reduce AoA, add power, level wings) and re-establish.

3. Altitude loss in turns

What it looks like: during a 30° banked turn in slow flight, the altimeter unwinds 50–100 ft.

Why: stall speed increases with bank (V_S × √n; at 30° bank, n = 1.15, so V_S rises by about 7%). The airplane is closer to stall in the turn, AND back pressure must increase to hold altitude under load factor. Either is hard alone; both at once is the common failure.

Fix: anticipate the back pressure. Add back pressure as you roll in. If the stall warning activates, reduce bank first, not back pressure — bank reduces load factor and stall margin returns.

4. Altitude gain on power addition

What it looks like: when adding power to climb or hold altitude, the airplane balloons up — gains 100–200 ft unexpectedly.

Why: the pilot added power as the primary altitude control (correct) but didn't anticipate the pitch couple (engine pushes nose up). Trim is also still set for the low-power slow-flight pitch, so the trim helps the climb.

Fix: forward elevator pressure as power increases, similar to the go-around trim management (H). Re-trim progressively as the airplane stabilizes at the new configuration.

5. Uncoordinated flight — drift / wing drop

What it looks like: the airplane drifts heading without a turn input, or the wings drop momentarily as the pilot adds bank.

Why: insufficient rudder at high AoA. Left-turning tendencies are amplified; without active right rudder, the airplane yaws left.

Fix: active right rudder pressure continuously. Use the ball as the diagnostic — center it, hold it centered, even if it requires more rudder than feels natural.

6. Over-controlling primary axes

What it looks like: the pilot makes large, frequent pitch or roll corrections; the airplane oscillates around the target altitude and heading.

Why: treating slow flight like cruise — expecting the same control response, getting delayed response, correcting more, then over-correcting.

Fix: small inputs, then wait. The airplane is responding slowly; corrections need to be measured against the actual response, not against cruise expectations.

7. Premature flap retraction on recovery

What it looks like: during recovery to cruise, the pilot retracts flaps fully before the airplane has accelerated above the published flap-up speed. The airplane sinks abruptly.

Why: habit from normal-takeoff retraction order, or impatience to get back to cruise.

Fix: retract incrementally as airspeed builds past each flap-limit speed. Same discipline as a go-around (H, ERR #4): partial first, verify airspeed, then next stage.

How errors compound. Bank-induced stall speed (#3) and uncoordinated flight (#5) are the dangerous pair — together they're the kill chain for a base-to-final stall-spin (cross-ref VII.D for the spin pedagogy). Slow flight at high AoA + bank + uncoordinated = exactly the condition that produces an inadvertent spin. The discipline that prevents this: rudder active, bank conservative, recognize the warning. The maneuver is safe at altitude with margin; the same regime on final approach is not.