Federal Aviation Administration, DOT

Section 25.523

each of the prescribed landing conditions. However, for the drift landing
condition of Section 25.485, 100 percent of the
vertical load must be applied.
(e) Taxiing and ground handling conditions. For one and for two deflated
tires - 
(1) The applied side or drag load factor, or both factors, at the center of
gravity must be the most critical value
up to 50 percent and 40 percent, respectively, of the limit side or drag load
factors, or both factors, corresponding
to the most severe condition resulting
from consideration of the prescribed
taxiing and ground handling conditions;
(2) For the braked roll conditions of
Section 25.493 (a) and (b)(2), the drag loads on
each inflated tire may not be less than
those at each tire for the symmetrical
load distribution with no deflated tires;
(3) The vertical load factor at the
center of gravity must be 60 percent
and 50 percent, respectively, of the factor with no deflated tires, except that
it may not be less than 1g; and
(4) Pivoting need not be considered.
(f) Towing conditions. For one and for
two deflated tires, the towing load,
FTOW, must be 60 percent and 50 percent,
respectively, of the load prescribed.

spaschal on DSK3GDR082PROD with CFR

Section 25.519 Jacking and tie-down provisions.
(a) General. The airplane must be designed to withstand the limit load conditions resulting from the static
ground load conditions of paragraph (b)
of this section and, if applicable, paragraph (c) of this section at the most
critical
combinations
of
airplane
weight and center of gravity. The maximum allowable load at each jack pad
must be specified.
(b) Jacking. The airplane must have
provisions for jacking and must withstand the following limit loads when
the airplane is supported on jacks - 
(1) For jacking by the landing gear at
the maximum ramp weight of the airplane, the airplane structure must be
designed for a vertical load of 1.33
times the vertical static reaction at
each jacking point acting singly and in
combination with a horizontal load of
0.33 times the vertical static reaction
applied in any direction.

(2) For jacking by other airplane
structure at maximum approved jacking weight:
(i) The airplane structure must be designed for a vertical load of 1.33 times
the vertical reaction at each jacking
point acting singly and in combination
with a horizontal load of 0.33 times the
vertical static reaction applied in any
direction.
(ii) The jacking pads and local structure must be designed for a vertical
load of 2.0 times the vertical static reaction at each jacking point, acting
singly and in combination with a horizontal load of 0.33 times the vertical
static reaction applied in any direction.
(c) Tie-down. If tie-down points are
provided, the main tie-down points and
local structure must withstand the
limit loads resulting from a 65-knot
horizontal wind from any direction.
[Doc. No. 26129, 59 FR 22102, Apr. 28, 1994]

WATER LOADS
Section 25.521

General.

(a) Seaplanes must be designed for
the water loads developed during takeoff and landing, with the seaplane in
any attitude likely to occur in normal
operation, and at the appropriate forward and sinking velocities under the
most severe sea conditions likely to be
encountered.
(b) Unless a more rational analysis of
the water loads is made, or the standards in ANC-3 are used, SectionSection 25.523
through 25.537 apply.
(c) The requirements of this section
and SectionSection 25.523 through 25.537 apply also to
amphibians.
Section 25.523 Design weights and center of
gravity positions.
(a) Design weights. The water load requirements must be met at each operating weight up to the design landing
weight except that, for the takeoff condition prescribed in Section 25.531, the design
water takeoff weight (the maximum
weight for water taxi and takeoff run)
must be used.
(b) Center of gravity positions. The
critical centers of gravity within the
limits for which certification is requested must be considered to reach

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