AMC 22.443 Vertical tail surfaces

CAA ORS9 Decision No. 1

Gust loads

For sailplanes where the horizontal tail is supported by the vertical tail, the tail surfaces and their supporting structure including the rear portion of the fuselage should be designed to withstand the prescribed loadings on the vertical tail and the rolling moment induced by the horizontal tail acting in the same direction.

For T-tails in the absence of a more rational analysis, the rolling moment induced by gust load may be computed as follows:

where:

Mr = induced rolling moment horizontal tail (Nm)

b_v = span of vertical tail, measured from the bottom of the fuselage

This formula is only valid for vertical tail aspect ratios between 1 and 1.8 (with span and area measured from the bottom of the fuselage) and horizontal tail with no dihedral and aspect ratio 6 or less. For configurations in excess of these limits more detailed rational analysis will be required.