CS 22.425  Gust loads

CAA ORS9 Decision No. 1

In the absence of a more rational analysis, the horizontal tail loads must be computed as follows: 

where: 

P   = horizontal tail load (N) 

P_o  =  horizontal tail balancing load acting on the horizontal tail before the appearance of the gust (N)  ρ_o   =  density of air at sea-level (kg/m³)  S_t    =  area of horizontal tail (m²) 

a_h  =  slope of horizontal tail lift curve per radian  U   =  gust speed (m/s)  kH =  gust factor. In the absence of a rational analysis the same value may be taken as for the wing. 

V   =  speed of flight (m/s)

=  rate of change of downwash angle with wing angle of attack