The Beginner’s Guide to Aircraft Shock Absorbers

Trailing arm suspension

When inspecting the landing gear on a typical airplane, you can expect to find shock absorbers. There are wheels, and there are shock absorbers. Shock absorbers play an important role in aircraft landing gear by allowing for smooth, safe landings. What are shock absorbers exactly, and how do they work?

What Are Shock Absorbers?

Shock absorbers are suspension systems that, as the name suggests, are designed to absorb shock. Airplanes land with an enormous amount of force. A typical 747 may weigh nearly a half-million pounds. All of that weight touching down on a runway can damage the airplane. Fortunately, 747s and many other airplanes are equipped with shock absorbers.

Shock absorbers are found in the landing gear. When an airplane lands, they will typically flex or retract while subsequently absorbing shock, The end result is a smooth landing that protects the airplane from damage and the passengers from injury.

The Different Types of Shock Absorbers

There are two primary types of shock absorbers found on airplanes: solid shock absorbers and oleo struts. Solid shock absorbers, as the name suggests, are solid. They may consist of metal rods that, when exposed to shock, will flex. Solid shock absorbers such as this are the most basic, and they are usually limited to small airplanes.

Oleo struts are a more advanced type of shock absorber. They use pressurized air or oil to absorb shock. Most oleo struts feature a cylinder. Within this cylinder is air or oil. Upon touching down on a runway, the landing force will move a piston into this cylinder, thus pressurizing the contained air or oil.

Shock Absorbers and Nitrogen-Filled Tires

In addition to shock absorbers, many airplanes feature nitrogen-filled tires. The tires on the landing gear wheels aren’t filled with air. Instead, they are filled with nitrogen gas.

Nitrogen helps to keep moisture out of the tires. There’s usually at least some moisture in plain air. Nitrogen, however, is devoid of moisture. By filling the tires with nitrogen, aerospace companies don’t have to worry about moisture contamination degrading the inner walls of the tires.

In Conclusion

Contrary to popular belief, the landing gear on most airplanes isn’t limited to wheels. Aircraft landing gear contains other components, such as shock absorbers. Shock absorbers are suspension systems that live up to their namesake by absorbing shock. Some airplanes use solid shock absorbers, whereas others use oleo struts.