Enter your groundspeed and get your pivotal altitude instantly in feet AGL, plus the MSL altitude over your terrain.
Educational only — always fly your POH & current weatherEducational estimates only — not for flight planning or dispatch. Fly the maneuver per the Airplane Flying Handbook and your instructor.
In eights on pylons there's one altitude where your wingtip reference line stays pinned to the pylon — the pivotal altitude. It depends only on groundspeed: GS² ÷ 11.3. Enter your groundspeed to get it in feet AGL (and MSL over your terrain), then read why it keeps changing as the wind swings your groundspeed around the turn.
Groundspeed, not airspeed — that's the whole trick of the maneuver. Add your terrain elevation to see the MSL altitude to fly.
Pivotal altitude (ft AGL) = groundspeed² ÷ 11.3 with groundspeed in knots (÷ 15 for mph). At 100 kt that's 885 ft AGL; at 110 kt, 1,071 ft. The physics: at exactly this height, your angular rate around the pylon matches the rate the pylon's bearing changes, so the lateral reference line appears frozen on it.
| Groundspeed | Pivotal altitude |
|---|---|
| 90 kt | 717 ft AGL |
| 100 kt | 885 ft AGL |
| 110 kt | 1,071 ft AGL |
| 120 kt | 1,274 ft AGL |
| 130 kt | 1,496 ft AGL |
Why you're always climbing or descending: the wind changes your groundspeed continuously around the pylon — fastest on the downwind side, slowest upwind. Since pivotal altitude tracks GS², you climb as you accelerate through the downwind side and descend as you slow on the upwind side. The visual cue closes the loop: if the pylon appears to move ahead of your wingtip reference line, you're above the pivotal altitude for your current groundspeed — descend. If the pylon appears to fall behind the line, you're below it — climb.
Commercial-checkride staple: examiners love asking for the pivotal altitude at your entry groundspeed. Compute a table for your typical maneuvering speeds before the ride — and remember your entry altitude also has to respect minimum-safe-altitude rules over the terrain. High-elevation practice areas change your density altitude and the true airspeed behind any groundspeed — cross-check with the TAS calculator on hot days.
High, hot practice areas raise the true airspeed behind every groundspeed. Our guide explains how to calculate density altitude.
Square the groundspeed in knots and divide by 11.3 to get feet AGL (with mph, divide by 15). At 100 kt groundspeed: 100² ÷ 11.3 ≈ 885 ft AGL. Add terrain elevation for the MSL altitude to fly.
Because it depends on groundspeed squared, and wind changes your groundspeed around each pylon — highest downwind, lowest upwind. You continuously descend into the upwind side and climb on the downwind side to stay on the pivotal altitude.
The pylon appearing to move ahead means you are above the pivotal altitude for your current groundspeed — descend. If the pylon drifts behind the line, you are below pivotal altitude — climb. It ties back to the wind: groundspeed builds on the downwind side, raising the pivotal altitude, so you find yourself below it, the pylon starts slipping behind the line, and you climb.
No — only groundspeed. Bank angle determines how far from the pylon you fly (steeper bank, closer pylon), and indicated airspeed matters only through the groundspeed it produces with the wind. That's what makes the maneuver such a good test of wind awareness.
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