Code of Federal Regulations - Title 14

667

Federal Aviation Administration, DOT

§ 27.733

=the load factor developed, during impact,

on the mass used in the drop test (i.e.,
the acceleration

dv/dt in g’s recorded in

the drop test plus 1.0).

§ 27.727

Reserve energy absorption

drop test.

The reserve energy absorption drop

test must be conducted as follows:

(a) The drop height must be 1.5 times

that specified in § 27.725(a).

(b) Rotor lift, where considered in a

manner similar to that prescribed in
§ 27.725(b), may not exceed 1.5 times the
lift allowed under that paragraph.

this test without collapsing. Collapse
of the landing gear occurs when a
member of the nose, tail, or main gear
will not support the rotorcraft in the
proper attitude or allows the rotorcraft
structure, other than the landing gear
and external accessories, to impact the
landing surface.

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–26, 55 FR 8001, Mar. 6,
1990]

§ 27.729

Retracting mechanism.

For rotorcraft with retractable land-

ing gear, the following apply:

(a)

Loads. The landing gear, retract-

ing mechansim, wheel-well doors, and
supporting structure must be designed
for—

(1) The loads occurring in any ma-

neuvering condition with the gear re-
tracted;

(2) The combined friction, inertia,

and air loads occurring during retrac-
tion 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 extended
speed.

(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 equivalent en-
ergy.

(d)

Operation tests. The proper func-

tioning 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 posi-
tions.

(f)

Control. The location and oper-

ation 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.

[Amdt. 27–21, 49 FR 44434, Nov. 6, 1984]

§ 27.731

Wheels.

(a) Each landing gear wheel must be

approved.

(b) The maximum static load rating

of each wheel may not be less than the
corresponding static ground reaction
with—

(1) Maximum weight; and
(2) Critical center of gravity.
(c) The maximum limit load rating of

each wheel must equal or exceed the
maximum radial limit load determined
under the applicable ground load re-
quirements of this part.

§ 27.733

Tires.

(a) Each landing gear wheel must

have a tire—

(1) That is a proper fit on the rim of

the wheel; and

(2) Of the proper rating.
(b) The maximum static load rating

of each tire must equal or exceed the
static ground reaction obtained at its
wheel, assuming—

(1) The design maximum weight; and
(2) The most unfavorable center of

gravity.

able landing gear system must, at the
maximum size of the tire type expected

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