PA.V.C.TOL· Tolerances
ACS tolerances
ACS tolerances for s-turns across a road
The Private Pilot Airplane ACS (FAA-S-ACS-6C, effective May 31, 2024) sets two numerical tolerances plus three structural requirements for s-turns across a road. As with all ground reference maneuvers, the numerical tolerances are anchored to entry values the DPE writes down before you begin.
The tolerances at a glance
| Parameter | Target | Tolerance | Reference |
|---|---|---|---|
| Altitude | Entry altitude (600–1,000 ft AGL) | ±100 ft | V.C.S3 |
| Airspeed | Entry airspeed | ±10 KIAS | V.C.S3 |
Plus three structural requirements:
- Equal semicircle radii on each side of the road — V.C.S2
- Wings-level perpendicular crossings of the road each pass — V.C.S4
- Downwind entry perpendicular to the road — V.C.S1
Altitude ±100 ft
Anchored to the entry altitude (within the 600–1,000 ft AGL band). Most altitude busts happen during the first semicircle's steep portion, where bank is highest and load factor demands more back pressure. Anticipate it the same way you do in a steep turn (A).
Airspeed ±10 KIAS
Anchored to the entry airspeed. The usual failure mode is over-pulling on the elevator to hold altitude during the steep downwind semicircle, which drags the airspeed below the band.
Equal semicircle radii
The DPE evaluates the ground track from above (or from observation during checkride debrief). The two semicircles on opposite sides of the road must be the same size — if the downwind one bulges and the upwind one tightens, the bank-with-groundspeed modulation is wrong, and this is the most common S-turn bust after altitude.
Wings-level at the road
Each road crossing must be wings-level and perpendicular to the road. Rolling-out late means crossing the road with a residual bank — fail. Rolling out early means a wings-level segment over the wrong side of the road, then a roll-in at the road — also fail. The roll-out must terminate exactly at the road.
Downwind entry
V.C.S1 requires entering perpendicular to the road on a downwind heading. Entering upwind, or entering off-perpendicular, is an automatic S1 failure. Identify wind direction before you commit; on most checkrides this is verbalized to the DPE before the first crossing.
★ Next up
PA.V.C.PRI · Principles & why
S-turns build on the rectangular course (B) by replacing four discrete bank changes with continuous bank modulation through each semicircle. The bank-with-gr…