Sec. 27.729 - Retracting mechanism.
For rotorcraft with retractable landing gear, the
(a) Loads. The landing gear, retracting mechansim, wheel-well
doors, and supporting structure must be designed for --
(1) The loads occurring in any maneuvering condition with the gear
(2) The combined friction, inertia, and air loads occurring during
retraction and extension at any airspeed up to the design maximum landing
gear operating speed; and
(3) The flight loads, including those in yawed flight, occurring with
the gear extended at any airspeed up to the design maximum landing gear
(b) Landing gear lock. A positive means must be provided to keep
the gear extended.
(c) Emergency operation. When other than manual power is used to
operate the gear, emergency means must be provided for extending the gear
in the event of --
(1) Any reasonably probable failure in the normal retraction system; or
(2) The failure of any single source of hydraulic, electric, or
(d) Operation tests. The proper functioning of the retracting
mechanism must be shown by operation tests.
(e) Position indicator. There must be a means to indicate to the
pilot when the gear is secured in the extreme positions.
(f) Control. The location and operation of the retraction
control must meet the requirements of §§27.777 and 27.779.
(g) Landing gear warning. An aural or equally effective landing
gear warning device must be provided that functions continuously when the
rotorcraft is in a normal landing mode and the landing gear is not fully
extended and locked. A manual shutoff capability must be provided for the
warning device and the warning system must automatically reset when the
rotorcraft is no longer in the landing mode.