Density Altitude Ground Effect Knot 
Plane and Pilot
JULY 1, 2025
A witness reported that they saw the airplane lift off from the runway and remain in ground effect until it crossed the departure end of the runway. The calculated density altitude was 4,790 feet. About 10 minutes later, the airplane was less than 100 feet above ground level, with a ground speed of about 61 knots.
Flight Training Central
SEPTEMBER 9, 2024
What is ground effect? What effect does high density altitude have on aircraft performance? What is the headwind component for a landing on Runway 18 if the tower reports the wind as 215° at 30 knots? Ground effect is most likely to result in which problem? It increases takeoff performance.
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Air Facts
SEPTEMBER 9, 2024
An incomplete summary description of FASF is whether the airplane made it out of ground effect. That phenomenon is best named Failure to Achieve Sustained Flight (FASF). This is more theoretical than practical for visual AOA, but can affect some proposals such as a general aviation stick shaker. No math required.
Chess In the Air
JUNE 24, 2022
This is consistent with Rick’s report, which referenced 9 knots of wind. At this point his ground speed was 81 kts, which – in still air – would reflect a normal pattern speed of approx. 65 kts IAS given the high density altitude. He may have expected an easy and uneventful landing.
Plane and Pilot
OCTOBER 3, 2024
We routinely taxi at 1200 rpm due to the low spray…[we] can cruise at 10 knots” in displacement mode, something a Goose can’t do. Early on a speed restriction of 130 knots was applied as a flutter issue. This was resolved on the kit version and led to cruising at 50% power and 120 knots, which proved to be the Gweduck’s sweet spot.
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