Sec. 25.473 - Landing load conditions and
(a) For the landing conditions specified
in §25.479 to §25.485 the airplane is assumed to contact the ground --
(1) In the attitudes defined in §25.479
(2) With a limit descent velocity of 10
fps at the design landing weight (the maximum weight for landing
conditions at maximum descent velocity); and
(3) With a limit descent velocity of 6
fps at the design take-off weight (the maximum weight for landing
conditions at a reduced descent velocity).
(4) The prescribed descent velocities
may be modified if it is shown that the airplane has design features that
make it impossible to develop these velocities.
(b) Airplane lift, not exceeding
airplane weight, may be assumed unless the presence of systems or
procedures significantly affects the lift.
(c) The method of analysis of airplane
and landing gear loads must take into account at least the following
(1) Landing gear dynamic
(2) Spin-up and springback.
(3) Rigid body response.
(4) Structural dynamic response of the
airframe, if significant.
(d) The landing gear dynamic
characteristics must be validated by tests as defined in §25.723(a).
(e) The coefficient of friction between
the tires and the ground may be established by considering the effects of
skidding velocity and tire pressure. However, this coefficient of friction
need not be more than 0.8.
[Amdt. 25-91, 62 FR 40705, July 29, 1997; Amdt.
25-91, 62 FR 45481, Aug. 27, 1997; Amdt 25-103, 66 FR 27394, May 16, 2001]