In determining the ground loads on the tail wheel and affected supporting structures, the following apply:
(a) For the obstruction load, the limit ground reaction obtained in the tail down landing condition is assumed to act up and aft through the axle at 45 degrees. The shock absorber and tire may be assumed to be in their static positions.
(b) For the side load, a limit vertical ground reaction equal to the static load on the tail wheel, in combination with a side component of equal magnitude, is assumed. In addition--
(1) If a swivel is used, the tail wheel is assumed to be swiveled 90 degrees to the airplane longitudinal axis with the resultant ground load passing through the axle;
(2) If a lock, steering device, or shimmy damper is used, the tail wheel is also assumed to be in the trailing position with the side load acting at the ground contact point; and
(3) The shock absorber and tire are assumed to be in their static positions.
(c) If a tail wheel, bumper, or an energy absorption device is provided to show compliance with Sec. 23.925(b), the following apply:
(1) Suitable design loads must be established for the tail wheel, bumper, or energy absorption device; and
(2) The supporting structure of the tail wheel, bumper, or energy absorption device must be designed to withstand the loads established in paragraph (c)(1) of this section. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-48, 61 FR 5147, Feb. 9, 1996]