Types of Landing Gear can be further divided up into

• Cantilever
• Semi cantilever
• Braced structure

Cantilever

Usually employed on the small aircraft, although in clean design it has been used in larger aircraft. It consists of shock absorber attached at its upper end to the aircraft structure and its lower and carried the wheel and the axle. These types do not generally retract and are ‘faired off’ to reduce aerodynamic drag and are satisfactory up to speed of 150 knots.

Semi Cantilever and Braced

These are similar and used commonly on aircraft with a retracting landing gear. In this design the shock absorber has a pivoted attachment at its upper end to the aircraft structure, and is braced sideways by a folding strut anchored to a point on the leg, and connected to the aircraft structure at its upper end. To effect retraction the strut can be broken by means of hydraulic jack, which also drives the leg upwards to full retraction. This jack may also be used to operate the locks which are mandatory at the up and down positions.

Maintenance

Oleo-pneumatic undercarriage should be subjected to inspections similar to those recommended for spring and rubber chord types, such as examinations for cracks or damage to mounting structure, corrosion and wear at pivot points. In addition following maintenance is necessary.

• Machined surfaces of the strut inner cylinder should be wiped free of dust or dirt at frequent intervals, to prevent damage to the lower cylinder seals. A lint free cloth, soaked in the fluid used in the strut, should be used for this purpose.
• The extension of the inner cylinder, that is the length of the visible portion of the inner cylinder, should be checked frequently against the center of gravity/loading graphs provided in the approved Maintenance Manual.
• The strut should be inspected frequently for fluid leaks. If leaks are due to faulty glands the glands may be replaced, but if they are due to a scored inner cylinder, the strut should be changed.
• Torque links, steering arms and damper attachments should be checked for security and for cracks, wear or any other damage.
• All moving parts of the undercarriage should be lubricated on assembly, and at the intervals specified in the approved Maintenance Manual.