(3) The combination of vertical and drag components considered to be acting at the main wheel axle centerline.
(b) For the tail-down landing condition for airplanes with tail wheels, the main and tail wheels are assumed to contact the ground simultaneously, in accordance with figure 3 of appendix A. Ground reaction conditions on the tail wheel are assumed to act—
(1) Vertically; and
(2) Up and aft through the axle at 45 degrees to the ground line.
(c) For the tail-down landing condition for airplanes with nose wheels, the airplane is assumed to be at an attitude corresponding to either the stalling angle or the maximum angle allowing clearance with the ground by each part of the airplane other than the main wheels, in accordance with figure 3 of appendix A, whichever is less.
[Docket No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25–91, 62 FR 40705, July 29, 1997; Amdt. 25–94, 63 FR 8848, Feb. 23, 1998]