(a) Each closed cabin must have at least one adequate and easily
accessible external door.
(b) Each external door must be located, and appropriate operating
procedures must be established, to ensure that persons using the door will
not be endangered by the rotors, propellers, engine intakes, and exhausts
when the operating procedures are used.
(c) There must be means for locking crew and external passenger doors
and for preventing their opening in flight inadvertently or as a result of
mechanical failure. It must be possible to open external doors from inside
and outside the cabin with the rotorcraft on the ground even though
persons may be crowded against the door on the inside of the rotorcraft.
The means of opening must be simple and obvious and so arranged and marked
that it can be readily located and operated.
(d) There must be reasonable provisions to prevent the jamming of any
external doors in a minor crash as a result of fuselage deformation under
the following ultimate inertial forces except for cargo or service doors
not suitable for use as an exit in an emergency:
(1) Upward -- 1.5g.
(2) Forward -- 4.0g.
(3) Sideward -- 2.0g.
(4) Downward -- 4.0g.
(e) There must be means for direct visual inspection of the locking
mechanism by crewmembers to determine whether the external doors
(including passenger, crew, service, and cargo doors) are fully locked.
There must be visual means to signal to appropriate crewmembers when
normally used external doors are closed and fully locked.
(f) For outward opening external doors usable for entrance or egress,
there must be an auxiliary safety latching device to prevent the door from
opening when the primary latching mechanism fails. If the door does not
meet the requirements of paragraph (c) of this section with this device in
place, suitable operating procedures must be established to prevent the
use of the device during takeoff and landing.
(g) If an integral stair is installed in a passenger entry door that is
qualified as a passenger emergency exit, the stair must be designed so
that under the following conditions the effectiveness of passenger
emergency egress will not be impaired:
(1) The door, integral stair, and operating mechanism have been
subjected to the inertial forces specified in paragraph (d) of this
section, acting separately relative to the surrounding structure.
(2) The rotorcraft is in the normal ground attitude and in each of the
attitudes corresponding to collapse of one or more legs, or primary
members, as applicable, of the landing gear.
(h) Nonjettisonable doors used as ditching emergency exits must have
means to enable them to be secured in the open position and remain secure
for emergency egress in sea state conditions prescribed for ditching.