14 CFR · Part 27
14 CFR § 27.505
Ski landing conditions.
If certification for ski operation is requested, the rotorcraft, with skis, must be designed to withstand the following loading conditions (where P is the maximum static weight on each ski with the rotorcraft at design maximum weight, and n is the limit load factor determined under § 27.473(b).
Up-load conditions in which—
A vertical load of Pn and a horizontal load of Pn/4 are simultaneously applied at the pedestal bearings; and
A vertical load of 1.33 P is applied at the pedestal bearings.
A side-load condition in which a side load of 0.35 Pn is applied at the pedestal bearings in a horizontal plane perpendicular to the centerline of the rotorcraft.
A torque-load condition in which a torque load of 1.33 P (in foot pounds) is applied to the ski about the vertical axis through the centerline of the pedestal bearings.
Regulations Referenced
Reflects the eCFR edition current as of September 29, 2026. Retrieved from ecfr.gov on October 16, 2026.
Primary Source