L2: Landing Gear Systems

Converted into heat energy

True shock absorption occurs when the shock energy of landing impact is ____, as in a shock strut landing gear.

Shock Struts

_____ are self-contained hydraulic units that support an aircraft while on the ground and protect the structure during landing. They must be inspected and serviced regularly to ensure proper operation.

Pneumatic/hydraulic

A typical ____ shock strut uses compressed air or nitrogen combined with hydraulic fluid to absorb and dissipate shock loads. (Often referred as air/oil or oleo strut)

Telescoping cylinders or tubes

Shock strut is constructed of two ____ that are closed on the external ends

Upper Cylinder

Fixed to the aircraft and does not move

Lower Cylinder

called the piston and is free to slide in and out of the upper cylinder.

ORIFICE

located between the two cylinders provides a passage for the fluid from the bottom chamber to enter the top cylinder chamber when the strut is compressed.

Fluid Flow

____ during shock strut operation is controlled by the taper of the metering pin in the shock strut orifice

Valve fitting assembly

The upper cylinder of a shock strut typically contains a ____

Near the top of the cylinder

Valve fitting assembly is located at ____. The valve provides a means of filling the strut with hydraulic fluid and inflating it with air or nitrogen as specified by the manufacturer

Bleeding Shock Strut

Shock struts contain an instruction plate that gives directions for filling the strut with fluid and for inflating the strut.

Filler inlet and air valve assembly

Hydraulic fluid

The instruction plate is usually attached near ____. It specifies the correct type of ____ to use in the strut and the pressure to which the strut should be inflated.

3,000

2,000

The AN6287-1 valve in Figure A has a valve core assembly and is rated to ____ pounds per square inch (psi). However, the core itself is only rated to ____ psi. The MS28889-1 valve in Figure B. has no valve core.

Torque Links or Torque Arms

To keep the piston and wheels aligned, most shock struts are equipped with ____. Retains the piston in the end of the upper cylinder when the strut is extended, such as after takeoff.