Airglas, Inc.
Manual # LH4000-GA8-105
5 | P a g e
MANUAL REVISION (B) December 12, 2018
THIS MANUAL INCLUDES INFORMATION PROPRIETARY TO
Airglas, Inc.
AND SHALL NOT BE USED TO MANUFACTURE OR REPRODUCE ANY PART OR
ASSEMBLY WITHOUT THE PRIOR WRITTEN PERMISSION OF
Airglas, Inc.
1.0 Introduction & Description
Introduction: Since 1955
Airglas, Inc.
has designed and manufactured composite skis that
dramatically increase the usefulness of the aircraft by allowing it to operate on snow or frozen
surfaces. The installation of the LH4000-GA8 hydraulic wheel ski kit allows the GA8 series of aircraft
to operate on paved or hard surfaces, and snow. With the ski retracted the tires protrude allowing
normal ground operations. When desired, the skis are extended by a hydraulic cylinder on each ski
and an electric/hydraulic pump to provide operating pressure. The ski is pushed down as a sliding
door closes the opening in the ski and causes the tire to ride up on top of the door. The door closes
off the wheel opening, thus creating the performance characteristics of a “straight ski”. The simplicity
of this design allows for a low maintenance high performance ski kit. This is a design that Airglas,
Inc. started in 2004, using the LH4000 installation on Cessna 180/185 aircraft.
Description: The LH4000-GA8 ski installation consists of essentially 3 systems;
1. The Mechanical System –This includes the ski with all attaching hardware (interface to the
gear leg) and the rigging components.
2. The Hydraulic System –This includes hydraulic lines (both onboard and external), hydraulic
actuating cylinders (on the skis), all the hydraulic fittings on the skis, and the hydraulic pumps.
3. The Electrical System –This includes pressure switches, a circuit breaker, wiring, control
switches and indicator lights (the electric pumps are covered under the hydraulic system).
Instructions for installation of this kit are detailed within this manual.
2.0 Control and Operation Information:
The doors for the skis are actuated by electric/hydraulic pumps located in the fuselage aft of
the baggage compartment. The main skis are actuated by one pump and the nose ski by
another pump. Each electric/hydraulic pump is controlled via a 3 position toggle switch and
indicator lights that are located on the instrument panel.
1. When the switch is lifted up, the cylinder will extend and slide the door under the tire. While
the switch is held up a yellow indicator light will illuminate (“IN TRANSIT TO SKIS”) showing
the ski position has been selected and the pump is energized. When the pump pressure
reaches 500 psi, a green light (“SKIS LOCKED DOWN”) will illuminate and stay on to confirm
adequate pressure for deployment of the skis has been reached. The switch is released, the IN
TRANSIT TO SKIS light will extinguish, but the SKIS LOCKED DOWN light will remain lit as
long as the pressure remains above 350 psi. Visual confirmation of the ski position is required
of the operator to confirm ski position.
2. When the switch is pressed down, the door will retract and expose the tire. While the switch is
held down a yellow indicator light (“IN TRANSIT TO WHEELS”) will illuminate showing the
wheel position has been selected and the pump is energized. When the pump pressure
