ACS tolerances

The Private Pilot Airplane ACS (FAA-S-ACS-6C, effective May 31, 2024) anchors normal-takeoff tolerances around the climb V-speed and runway alignment. Numerical busts are anchored to V_Y and the runway centerline; structural items cover power application, instruments, and wind correction.

The tolerances at a glance

Parameter	Target	Tolerance	Reference
Airspeed on climb	V_Y (best rate of climb)	+10 / −5 KIAS	V.A.S5
Runway alignment	Centerline	On centerline	V.A.S1
Pitch on rotation	Manufacturer's recommended attitude	Smooth, no over-rotation	V.A.S4

Plus structural requirements:

• Smooth power application to takeoff power — V.A.S3
• Confirm engine + flight instrument indications during the roll — V.A.S3
• Wind-drift correction in climb — V.A.S5
• Verify correct runway before takeoff — V.A.S1
• Position controls for existing wind — V.A.S2

Airspeed V_Y +10 / −5 KIAS

Asymmetric band: 10 knots fast is acceptable, only 5 knots slow. The reason is stall margin — slow climb is closer to stall, fast climb only sacrifices climb rate. If you can't hit V_Y exactly, err high.

V_Y itself comes from the POH and depends on weight (decreases as weight decreases) and density altitude (decreases as density altitude increases). The DPE knows the published number; use that unless POH conditions vary.

Centerline

V.A.S1 requires you to align on the centerline before applying takeoff power. Drift during the roll must be corrected with rudder, not nose-wheel steering once steering authority transitions to the rudder around 20–30 kt. A drift off centerline during the takeoff roll signals weak rudder coordination — bust risk.

Smooth power application

V.A.S3 requires takeoff power applied smoothly — full-power-slam is a bust marker for the DPE even if the takeoff otherwise goes well. Three to four seconds from idle to takeoff power is the typical pace.

Engine + instrument confirmation

You must look at the instruments and confirm normal indications during the roll: full RPM, oil pressure rising, airspeed alive, ammeter charging. Verbalizing "RPM full, oil pressure rising, airspeed alive" to the DPE during the roll is the standard demonstration.

Wind-drift correction in the climb

The runway centerline (extended) should track straight off the tail. If you drift, you're not crabbing enough — the DPE notes whether you actively manage drift or just let it happen.