FAA Federal Aviation Regulations (FARS, 14 CFR)

Under braked roll conditions with the shock absorbers in their static positions --

(a) The limit vertical load must be based on a load factor of at least --

(1) 1.33, for the attitude specified in §27.479(a)(1); and

(2) 1.0 for the attitude specified in §27.479(a)(2); and

(b) The structure must be designed to withstand at the ground contact point of each wheel with brakes, a drag load at least the lesser of --

(1) The vertical load multiplied by a coefficient of friction of 0.8; and

(2) The maximum value based on limiting brake torque.