Federal Aviation Administration, DOT

Section 27.305

(1) Section25 degrees from trim at a speed of
15 knots less than the speed for minimum rate of descent varying linearly
to Section10 degrees from trim at VNE;
(2) The steady state sideslip angles
established by Section 27.351;
(3) A sideslip angle selected by the
applicant, which corresponds to a
sideforce of at least 0.1g; or
(4) The sideslip angle attained by
maximum directional control input.
(b) Sufficient cues must accompany
the sideslip to alert the pilot when the
aircraft is approaching the sideslip
limits.
(c) During the maneuver specified in
paragraph (a) of this section, the sideslip angle versus directional control
position curve may have a negative
slope within a small range of angles
around trim, provided the desired heading can be maintained without exceptional piloting skill or alertness.
[Amdt. 27-44, 73 FR 11000, Feb. 29, 2008]

GROUND AND WATER HANDLING
CHARACTERISTICS
Section 27.231

General.

The rotorcraft must have satisfactory ground and water handling characteristics, including freedom from uncontrollable tendencies in any condition expected in operation.
Section 27.235

Taxiing condition.

The rotorcraft must be designed to
withstand the loads that would occur
when the rotorcraft is taxied over the
roughest ground that may reasonably
be expected in normal operation.
Section 27.239

Spray characteristics.

If certification for water operation is
requested, no spray characteristics
during taxiing, takeoff, or landing may
obscure the vision of the pilot or damage the rotors, propellers, or other
parts of the rotorcraft.

spaschal on DSK3GDR082PROD with CFR

Section 27.241

Ground resonance.

The rotorcraft may have no dangerous tendency to oscillate on the
ground with the rotor turning.

MISCELLANEOUS FLIGHT REQUIREMENTS
Section 27.251

Vibration.

Each part of the rotorcraft must be
free from excessive vibration under
each appropriate speed and power condition.

Subpart C - Strength Requirements
GENERAL
Section 27.301

Loads.

(a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service)
and ultimate loads (limit loads multiplied by prescribed factors of safety).
Unless otherwise provided, prescribed
loads are limit loads.
(b) Unless otherwise provided, the
specified air, ground, and water loads
must be placed in equilibrium with inertia forces, considering each item of
mass in the rotorcraft. These loads
must be distributed to closely approximate or conservatively represent actual conditions.
(c) If deflections under load would
significantly change the distribution of
external or internal loads, this redistribution must be taken into account.
Section 27.303

Factor of safety.

Unless otherwise provided, a factor of
safety of 1.5 must be used. This factor
applies to external and inertia loads
unless its application to the resulting
internal stresses is more conservative.
Section 27.305

Strength and deformation.

(a) The structure must be able to
support limit loads without detrimental or permanent deformation. At
any load up to limit loads, the deformation may not interfere with safe operation.
(b) The structure must be able to
support ultimate loads without failure.
This must be shown by - 
(1) Applying ultimate loads to the
structure in a static test for at least
three seconds; or
(2) Dynamic tests simulating actual
load application.

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