14 CFR · Part 25

14 CFR § 25.531

Hull and main float takeoff condition.

For the wing and its attachment to the hull or main float—

(a)

The aerodynamic wing lift is assumed to be zero; and

(b)

A downward inertia load, corresponding to a load factor computed from the following formula, must be applied:

where—

n = inertia load factor;

CTO = empirical seaplane operations factor equal to 0.004;

VS1 = seaplane stalling speed (knots) at the design takeoff weight with the flaps extended in the appropriate takeoff position;

β = angle of dead rise at the main step (degrees); and

W = design water takeoff weight in pounds.

Reflects the eCFR edition current as of September 29, 2026. Retrieved from ecfr.gov on October 16, 2026.

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