CS 25.499 Nose-wheel yaw and steering

(a)A vertical load factor of 1·0 at the aeroplane centre of gravity, and a side component at the nose wheel ground contact equal to 0·8 of the vertical ground reaction at that point are assumed.

(b)With the aeroplane assumed to be in static equilibrium with the loads resulting from the use of brakes on one side of the main landing gear, the nose gear, its attaching structure, and the fuselage structure forward of the centre of gravity must be designed for the following loads:

(1)A vertical load factor at the centre of gravity of 1·0.

(2)A forward acting load at the aeroplane centre of gravity of 0·8 times the vertical load on one main gear.

(3)Side and vertical loads at the ground contact point on the nose gear that are required for static equilibrium.

(4)A side load factor at the aeroplane centre of gravity of zero.

(c)If the loads prescribed in sub-paragraph (b) of this paragraph result in a nose gear side load higher than 0·8 times the vertical nose gear load, the design nose gear side load may be limited to 0·8 times the vertical load, with unbalanced yawing moments assumed to be resisted by aeroplane inertia forces.

(d)For other than the nose gear, its attaching structure, and the forward fuselage structure the loading conditions are those prescribed in sub-paragraph (b) of this paragraph, except that –

(1)A lower drag reaction may be used if an effective drag force of 0·8 times the vertical reaction cannot be reached under any likely loading condition; and

(2)The forward acting load at the centre of gravity need not exceed the maximum drag reaction on one main gear, determined in accordance with CS 25.493(b).

(e)With the aeroplane at design ramp weight, and the nose gear in any steerable position, the combined application of full normal steering torque and vertical force equal to 1·33 times the maximum static reaction on the nose gear must be considered in designing the nose gear, its attaching structure and the forward fuselage structure.