Stay on Course: Easy Ground Speed Checks En Route

Here’s how to quickly and accurately determine ground speed during flight without sacrificing heading or altitude.

Meg Godlewski

Wednesday, September 17, 2025 at 10:00 AM ET

Verified

Edited By:

Travis Tingle

A mechanical E6-B can help you do ground speed check in flight. [Courtesy: Meg Godlewski]

Key Takeaways:

To efficiently perform ground speed checks in flight without losing course or altitude, ensure the aircraft is trimmed for level flight and keep the E6-B's wind dot set from your pre-flight calculations.
During flight, if the actual time for a leg differs from your estimate, adjust the E6-B's B scale to align the actual time with the distance covered, then read the new ground speed at the index and leave it set for subsequent leg calculations.
Consistent ground practice with your E6-B, both mechanical and digital, is essential to build the speed and accuracy required for quick calculations with minimal in-flight distraction.

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Question: How can I do a ground speed check without going off course and altitude? I do the math on the ground to determine my ground speed using the mechanical E6-B. But when I do a ground speed check at altitude during the flight, it takes me so long that the aircraft drifts off heading and altitude. I am a student pilot flying a Cessna 172P that doesn’t have an autopilot. I tried using one of those calculator E6-Bs, and it didn’t help.

Answer: Are you trimming the aircraft for level flight once you are in cruise? That’s step one. Step two is making sure you don’t make more work for yourself by erasing the wind dot on the mechanical E6-B after you have completed your calculations on the ground.