for 0 [LESS THAN EQUAL TO]s [LESS THAN EQUAL TO]2H
where-
s = distance penetrated into the gust (feet);
Uds = the design gust velocity in equivalent airspeed specified in paragraph (a)(4) of this section; and
H = the gust gradient which is the distance (feet) parallel to the airplane's flight path for the gust to reach its peak velocity.
where-
Uref = the reference gust velocity in equivalent airspeed defined in paragraph (a)(5) of this section.
Fg = the flight profile alleviation factor defined in paragraph (a)(6) of this section.
Zmo = Maximum operating altitude defined in § 25.1527 (feet).
= PL-1g± UAA
Where-
PL = limit load;
PL-1g = steady 1g load for the condition;
A = ratio of root-mean-square incremental load for the condition to root-mean-square turbulence velocity; and
U[SIGMA] = limit turbulence intensity in true airspeed, specified in paragraph (b)(3) of this section.
Where-
H(©) = the frequency response function, determined by dynamic analysis, that relates the loads in the aircraft structure to the atmospheric turbulence; and
[PHI](©) = normalized power spectral density of atmospheric turbulence given by-
Where-
© = reduced frequency, radians per foot; and
L = scale of turbulence = 2,500 ft.
U[SIGMA] = U[SIGMA]ref Fg
Where-
U[SIGMA]ref is the reference turbulence intensity that varies linearly with altitude from 90 fps (TAS) at sea level to 79 fps (TAS) at 24,000 feet and is then constant at 79 fps (TAS) up to the altitude of 60,000 feet.
Fg is the flight profile alleviation factor defined in paragraph (a)(6) of this section;
AU[SIGMA] of the same load quantity in a linear approximated model.
Where-
PL = limit load;
PL-1g = steady 1g load for the condition;
LV = peak incremental response load due to a vertical gust according to § 25.341(a) ; and
LL = peak incremental response load due to a lateral gust according to § 25.341(a) .
14 C.F.R. §25.341