FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 9. Aircraft Systems and Components | 1. Inspection and Maintenance of Landing Gear | 9-8. Floats and Skis
AC 43.13-1B CHG 1
9/27/01
Amphibious aircraft have floats or a hull for
operating on water and retractable wheels for
land operation.
a. Skis are used for operating on snow
and ice. The skis may be made of wood,
metal, or composite materials. There are three
basic styles of skis. A conventional ski, shown
in figure 9-1, replaces the wheel on the axle.
The shock cord is used to hold the toe of the
ski up when landing. The safety cable and
check cable prevent the ski from pivoting
through too great an angle during flight.
b. The wheel ski is designed to mount on
the aircraft along with the tire. The ski has a
portion cut out that allows the tire to extend
slightly below the ski, so that the aircraft can
be operated from conventional runways with
the wheels or from snow or ice surfaces using
the ski. This arrangement has a small wheel
mounted on the heel of the ski, so that it does
not drag on conventional runways.
c. In retractable wheel-ski arrangements,
the ski is mounted on a common axle with the
wheel. In this arrangement, the ski can be ex-
tended below the level of the wheel for landing
on snow or ice. The ski can be retracted above
the bottom of the wheel for operations from
conventional runways. A hydraulic system is
commonly used for the retraction-system op-
eration.
FIGURE 9-1. A typical ski installation.
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