ACS tolerances

The Private Pilot Airplane ACS (FAA-S-ACS-6C, effective May 31, 2024) specifies four numerical tolerances for steep turns. All four are evaluated against the values you established at entry — the DPE writes them down before you roll in.

The four tolerances at a glance

Parameter	Target	Tolerance	Reference
Bank angle	Approximately 45° (Private Pilot)	±5°	V.A.S3
Altitude	Entry altitude	±100 ft	V.A.S5
Airspeed	POH-recommended (≤ VA)	±10 KIAS	V.A.S2, S5
Heading	Entry heading at roll-out	±10°	V.A.S5

Plus two non-numerical requirements:

• Coordinated flight throughout (ball centered) — V.A.S3
• Both directions (left and right, typically 360° each) — V.A.S4

Bank: 45° ±5°

The ACS says "approximately 45°" of bank for the Private Pilot. The acceptable band is 40°–50°. Below 40° isn't steep enough; above 50° is over-banked.

Don't confuse Private with Commercial. The Commercial Pilot Airplane ACS (FAA-S-ACS-7A) uses 50° bank for steep turns. Both standards have used these same values since the PTS-to-ACS transition in 2017 — the difference between certificates, not between revisions. Internet study materials sometimes blur the two; if a source quotes "50° for steep turns" without specifying the certificate, check the citation.

Altitude: ±100 ft

Measured against the entry altitude — the value showing on the altimeter when you began rolling in. The DPE expects you to call out the entry altitude verbally before the maneuver.

A common mistake: students think the tolerance refers to "any altitude during the maneuver." It doesn't. It's anchored to the entry altitude, and the altimeter must read within ±100 ft of that throughout.

Airspeed: ±10 KIAS

Anchored to the entry airspeed. The entry airspeed itself is set by V.A.S2:

1. Manufacturer's recommended airspeed, if the POH specifies one for steep turns.
2. Otherwise, a safe airspeed not to exceed VA for the current weight.

Be aware that VA decreases as weight decreases. A POH that publishes VA = 105 KIAS at 2,400 lb may have VA = 95 KIAS at 1,900 lb. Use the value for what the airplane actually weighs today.

Heading: ±10° at roll-out

Measured against the entry heading. You don't need to be on the entry heading mid-turn — only when the wings come back to level on roll-out. The standard assumes one full 360°; if you're flying 720° or some other multiple, the rule is "roll out on the heading you started on."

Required in both directions

V.A.S4 requires the maneuver "in the opposite direction." On a checkride, the DPE will typically call for a 360° to the left followed by a 360° to the right (or vice versa). The four tolerances apply to each direction independently — you don't get to average a tight left turn against a sloppy right one.

Coordination

The ball stays centered throughout. The ACS doesn't publish a numerical tolerance for slip-skid, but a clearly skidding or slipping turn fails V.A.S3 ("coordinated 360° steep turn"). On checkrides, this is usually only flagged when it's visibly out of trim.

What "outside tolerance" means

If you exceed any one of the four numerical tolerances during the maneuver, the standard is not satisfied. The DPE may give you a second attempt, but the original attempt is the one of record. Train to about half the tolerance so checkride nerves don't push you outside the actual limit.