JAR 25.785 Seats, berths, safety belts and
harnesses
(a) A seat (or berth for a non ambulant
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 aeroplane at each station
designated as occupiable during take-off 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 JAR 25.561 and
JAR 25.562.
(c) Each seat or berth must be approved.
(d) Each occupant of a seat (see ACJ
25.785(d)) that makes more than an 18-degree
angle with the vertical plane containing the
aeroplane centreline 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 JAR 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 JAR 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 JAR 25.395.
(3) For the determination of the
strength of the local attachments (see ACJ
25.561(c)) of –
(i) Each seat to the structure; and
(ii) Each belt or harness to the
seat or structure;
a multiplication factor of 1·33 instead of the
fitting factor as defined in JAR 25.625 should be
used for the inertia forces specified in JAR
25.561. (For the lateral forces according to JAR
25.561(b)(3) 1·33 times 3·0 g should be used.)
(g) Each crew member seat at a flight-deck
station must have a shoulder harness. These seats
must meet the strength requirements of sub-paragraph
(f) of this paragraph, except that where
a seat forms part of the load path, the safety belt
or shoulder harness attachments need only be
proved to be not less strong than the actual
strength of the seat. (See ACJ 25.785 (g).)
(h) Each seat located in the passenger
compartment and designated for use during take-
off and landing by a cabin crew member required
by the National Operating Rules must be –
(1) Near a required floor level
emergency exit, except that another location is
acceptable if the emergency egress of
passengers would be enhanced with that
location. A cabin crew member seat must be
located adjacent to each Type A emergency
exit. Other cabin crew member seats must
be evenly distributed among the required floor
level emergency exits to the extent feasible.
(2) To the extent possible, without
compromising proximity to a required floor
level emergency exit, located to provide a
direct view of the cabin area for which the
cabin crew member is responsible.
(3) Positioned so that the seat will not
interfere with the use of a passageway or exit
when the seat is not in use.
(4) Located to minimise the probability
that occupants would suffer injury by being
struck by items dislodged from service areas,
stowage compartments, or service equipment.
(5) Either forward or rearward facing
with an energy absorbing rest that is designed
to support the arms, shoulders, head and spine.
(6) Equipped with a restraint system
consisting of a combined safety belt and
shoulder harness unit with a single point
release. There must be means to secure each
restraint system when not in use to prevent
interference with rapid egress in an emergency.
(i) Each safety belt must be equipped with a
metal to metal latching device.
(j) If the seat backs do not provide a firm
handhold, there must be a handgrip or rail along
each aisle to enable persons to steady themselves
while using the aisles in moderately rough air.
(k) Each projecting object that would injure
persons seated or moving about the aeroplane in
normal flight must be padded.
(l) Each forward observer’s seat required by
the operating rules must be shown to be suitable
for use in conducting the necessary en-route
inspections.
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