Section 25.785

14 CFR Ch. I (1-1-19 Edition)

(4) The open door during flight would
not create aerodynamic interference
that could preclude safe flight and
landing.
(5) The airplane would meet the
structural design requirements with
the door open. This assessment must
include the aeroelastic stability requirements of Section 25.629, as well as the
strength requirements of subpart C of
this part.
(6) The unlatching or opening of the
door must not preclude safe flight and
landing as a result of interaction with
other systems or structures.

spaschal on DSK3GDR082PROD with CFR

[Doc. No. 2003-14193, 69 FR 24501, May 3, 2004]

Section 25.785 Seats, berths, safety belts, and
harnesses.
(a) A seat (or berth for a nonambulant person) must be provided for each
occupant who has reached his or her
second birthday.
(b) Each seat, berth, safety belt, harness, and adjacent part of the airplane
at each station designated as occupiable during takeoff and landing must
be designed so that a person making
proper use of these facilities will not
suffer serious injury in an emergency
landing as a result of the inertia forces
specified in SectionSection 25.561 and 25.562.
(c) Each seat or berth must be approved.
(d) Each occupant of a seat that
makes more than an 18-degree angle
with the vertical plane containing the
airplane centerline must be protected
from head injury by a safety belt and
an energy absorbing rest that will support the arms, shoulders, head, and
spine, or by a safety belt and shoulder
harness that will prevent the head
from contacting any injurious object.
Each occupant of any other seat must
be protected from head injury by a
safety belt and, as appropriate to the
type, location, and angle of facing of
each seat, by one or more of the following:
(1) A shoulder harness that will prevent the head from contacting any injurious object.
(2) The elimination of any injurious
object within striking radius of the
head.
(3) An energy absorbing rest that will
support the arms, shoulders, head, and
spine.

(e) Each berth must be designed so
that the forward part has a padded end
board, canvas diaphragm, or equivalent
means, that can withstand the static
load reaction of the occupant when
subjected to the forward inertia force
specified in Section 25.561. Berths must be free
from corners and protuberances likely
to cause injury to a person occupying
the berth during emergency conditions.
(f) Each seat or berth, and its supporting structure, and each safety belt
or harness and its anchorage must be
designed for an occupant weight of 170
pounds, considering the maximum load
factors, inertia forces, and reactions
among the occupant, seat, safety belt,
and harness for each relevant flight
and ground load condition (including
the emergency landing conditions prescribed in Section 25.561). In addition - 
(1) The structural analysis and testing of the seats, berths, and their supporting structures may be determined
by assuming that the critical load in
the forward, sideward, downward, upward, and rearward directions (as determined from the prescribed flight,
ground, and emergency landing conditions) acts separately or using selected
combinations of loads if the required
strength in each specified direction is
substantiated. The forward load factor
need not be applied to safety belts for
berths.
(2) Each pilot seat must be designed
for the reactions resulting from the application of the pilot forces prescribed
in Section 25.395.
(3) The inertia forces specified in
Section 25.561 must be multiplied by a factor
of 1.33 (instead of the fitting factor prescribed in Section 25.625) in determining the
strength of the attachment of each
seat to the structure and each belt or
harness to the seat or structure.
(g) Each seat at a flight deck station
must have a restraint system consisting of a combined safety belt and
shoulder harness with a single-point release that permits the flight deck occupant, when seated with the restraint
system fastened, to perform all of the
occupant-s necessary flight deck functions. There must be a means to secure
each combined restraint system when
not in use to prevent interference with
the operation of the airplane and with
rapid egress in an emergency.

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