Aircraft Servicing Air/Nitrogen, Oil And Fluids

In 1954, a hydro-pneumatic suspension system was introduced, using the same principles as the gas-compressed nitrogen fluid, but not only a motor-driven pump, but also a pressurized hydraulic fluid. The technology was further refined, and the Oleo strut alone was one of the first universal constructions to be used in aircraft. It used air pressure and hydraulic fluid to create a spring effect.

    

The purpose of oil and hydraulic fluid in an oleo strut is to dampen the effect of the gas in the spring in order to slow the speed at which the strut absorbs the landing shock, thereby slowing down the recoil after impact and minimizing the chance of a recursion on landing. To achieve this, the strut is equipped with an aperture that divides the lower fluid-carrying part of the strut into two chambers. In various designs and configurations, a strut can hold hydraulic fluid at the bottom of the section and a strut that compresses air and nitrogen at the top. The gas at the top of the struts acts like a spring and performs the same function as a steel spring, but instead of a simple spring type, the lower and upper types are equipped with high pressure seals to prevent liquid and gas from escaping, and with variable displacement chambers containing hydraulic fluid (bottom) and compressed air / nitrogen (top) that compresses and extends the strut.

    

Each strut contains compressed air or nitrogen at the top and hydraulic fluid at the bottom. The cavity between strut and piston is filled with gas (nitrogen, air or light aircraft oil) and the hydraulic fluid is divided into two chambers that communicate via small openings each other. When the strut is filled, the liquid on the strut has air, nitrogen and compressed air from the strut booster.

    

During maintenance, the strut can be dried with compressed air or nitrogen at the recommended pressure. Dispose of the canisters and tank sections and drain the hoses as needed to collect the old hydraulic fluid before pressing off the strut during maintenance.

    

When servicing an aircraft, you should consult the specific maintenance manual of the aircraft to determine the right type of service equipment and procedures. Hydraulic service and oil dispensers allow you to maintain and refill the oil in the hydraulic system with clean, uncontaminated fluid. These include hydraulic testing equipment and aircraft oil filters.

    

The inspection and maintenance of aircraft fluids is an important maintenance function. In order to maintain flight safety and extend the life of your aircraft, hydraulic maintenance and oil equipment is critical. Hydraulic units, also known as hydraulic mules, provide hydraulic pressure to operate aircraft systems during maintenance.

    

When servicing tires and struts with high-pressure nitrogen, technicians should exercise caution. When transporting jet aircraft for use, nitrogen is needed on the struts to dissipate much of the heat from landing and fueling hydraulic fluids produced when oxygen is on the struts. During maintenance and filtration, large quantities of fluid can be lost from the system, as the air is flushed out of the system when checking for leaks.

    

The most common type found in most aircraft is hydraulic oil in an air cylinder known as an oleo strut. The air oil in the strut is called shock absorber and must maintain the correct amount of air oil.

    

An oleo strut is a pneumatic, air-oiled hydraulic shock absorber used in the landing gear of most large and many smaller aircraft. Oleo struts are among the most reliable aircraft components used in aircraft landing gear that can withstand enormous loads and simpler designs.

    

The final blow of the bleeding process, with which the Cessna nose brace was filled with hydraulic fluid, is shown below, where the fluid in the hose comes from a solid stream of air. When the strut is low, the hydraulic fluid fills with air pressure and tends to stay in place. For example, when an aircraft lands, the pressure on the shock absorber increases to support the weight of the aircraft, which holds gas and hydraulic fluid together so that unreleased gas is absorbed by fluid.

    

Granville's Aircraft Hydraulic Strut Sealant is an FAA-approved product that is a mixture of hydraulic fluids added to the struts during the maintenance process. Different types of struts are used for shock absorption in aircraft. Aircraft dampers and shock absorbers use hydraulic cylinders to prevent rapid movement of the aircraft's main landing gear.

    

Provision of portable equipment for the maintenance of an aircraft's shock absorbers and landing gear assemblies, irrespective of weight of the aircraft, wheel configuration and whether they consist of a chamber containing hydraulic fluid, gas fluid or communication with each other. Key tools you need on the runway are air compressors, generators, hydraulic fluids, engine oil systems, and high and low pressure nitrogen systems. Air carts are used to generate a low pressure (below 50 psi) and a high airflow, which is used to start the engines, to heat and cool the aircraft from the ground using on-board systems.

    

The Malabar 8774C 3-cylinder Nitrogen Hydraulic Support Trolley reduces maintenance time for aircraft landing gear. The 250 Portable Maintenance Trolley (automated in the first version), shown in Figures 10a and 10b, is equipped with integrated service equipment to pump gas into the aircraft landing gear shock absorbers (102 degrees Celsius), refill the hydraulic fluid and inject the gas into the landing gear shock absorbers. It carries a pressure vessel (N 2 251), a gas delivery system (203) and a control system (205) to control the maintenance process. A person is stationed at the control valve of the service equipment, and when a person is at the station, they can observe the pressure of the aircraft systems.

    

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