Section 29.561

14 CFR Ch. I (1-1-19 Edition)
(4) Downward - 4.0g.

EMERGENCY LANDING CONDITIONS

spaschal on DSK3GDR082PROD with CFR

Section 29.561

General.

(a) The rotorcraft, although it may
be damaged in emergency landing conditions on land or water, must be designed as prescribed in this section to
protect the occupants under those conditions.
(b) The structure must be designed to
give each occupant every reasonable
chance of escaping serious injury in a
crash landing when - 
(1) Proper use is made of seats, belts,
and other safety design provisions;
(2) The wheels are retracted (where
applicable); and
(3) Each occupant and each item of
mass inside the cabin that could injure
an occupant is restrained when subjected to the following ultimate inertial load factors relative to the surrounding structure:
(i) Upward - 4g.
(ii) Forward - 16g.
(iii) Sideward - 8g.
(iv) Downward - 20g, after the intended displacement of the seat device.
(v) Rearward - 1.5g.
(c) The supporting structure must be
designed to restrain under any ultimate inertial load factor up to those
specified in this paragraph, any item of
mass above and/or behind the crew and
passenger compartment that could injure an occupant if it came loose in an
emergency landing. Items of mass to be
considered include, but are not limited
to, rotors, transmission, and engines.
The items of mass must be restrained
for the following ultimate inertial load
factors:
(1) Upward - 1.5g.
(2) Forward - 12g.
(3) Sideward - 6g.
(4) Downward - 12g.
(5) Rearward - 1.5g.
(d) Any fuselage structure in the area
of internal fuel tanks below the passenger floor level must be designed to
resist the following ultimate inertial
factors and loads, and to protect the
fuel tanks from rupture, if rupture is
likely when those loads are applied to
that area:
(1) Upward - 1.5g.
(2) Forward - 4.0g.
(3) Sideward - 2.0g.

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29-29, 54 FR 47319, Nov. 13,
1989; Amdt. 29-38, 61 FR 10438, Mar. 13, 1996]

Section 29.562 Emergency landing dynamic
conditions.
(a) The rotorcraft, although it may
be damaged in a crash landing, must be
designed to reasonably protect each occupant when - 
(1) The occupant properly uses the
seats, safety belts, and shoulder harnesses provided in the design; and
(2) The occupant is exposed to loads
equivalent to those resulting from the
conditions prescribed in this section.
(b) Each seat type design or other
seating device approved for crew or
passenger occupancy during takeoff
and landing must successfully complete dynamic tests or be demonstrated
by rational analysis based on dynamic
tests of a similar type seat in accordance with the following criteria. The
tests must be conducted with an occupant
simulated
by
a
170-pound
anthropomorphic test dummy (ATD),
as defined by 49 CFR 572, Subpart B, or
its equivalent, sitting in the normal
upright position.
(1) A change in downward velocity of
not less than 30 feet per second when
the seat or other seating device is oriented in its nominal position with respect to the rotorcraft-s reference system, the rotorcraft-s longitudinal axis
is canted upward 60Section with respect to
the impact velocity vector, and the
rotorcraft-s lateral axis is perpendicular to a vertical plane containing
the impact velocity vector and the
rotorcraft-s longitudinal axis. Peak
floor deceleration must occur in not
more than 0.031 seconds after impact
and must reach a minimum of 30g-s.
(2) A change in forward velocity of
not less than 42 feet per second when
the seat or other seating device is oriented in its nominal position with respect to the rotorcraft-s reference system, the rotorcraft-s longitudinal axis
is yawed 10Section either right or left of the
impact velocity vector (whichever
would cause the greatest load on the
shoulder harness), the rotorcraft-s lateral axis is contained in a horizontal
plane containing the impact velocity
vector, and the rotorcraft-s vertical

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