Aircraft landing gear is one of the essential systems of an aircraft. It plays an important role in supporting the aircraft's weight while it is on the ground, facilitating movement along the runway, and absorbing the shocks generated when the wheels make contact with the runway during landing. Designing this system requires a careful balance between strength, durability, and weight, while ensuring its ability to withstand different loads during takeoff, landing, and ground operations. The landing gear consists of several interconnected components, including wheels, tires, structural struts, shock absorption systems, and brakes. These components are manufactured from materials capable of withstanding repeated mechanical stresses, such as aluminum alloys, titanium alloys, and high-strength steel, while minimizing the overall weight of the aircraft. The selection of materials and the design of individual components directly affect the system's efficiency, service life, and resistance to mechanical fatigue. Shock absorption is one of the most important functions of aircraft landing gear, as the aircraft experiences forces when its vertical velocity changes rapidly upon contact with the runway. To reduce the impact of these forces, many aircraft use shock-absorbing struts that operate with oil and compressed gas. During landing, the piston moves inside the cylinder, compressing the gas and forcing the oil through carefully designed orifices. This process gradually absorbs the energy generated during landing and reduces the transmission of impact forces to the aircraft structure and passengers. In addition to shock absorption, load distribution plays a fundamental role in protecting the aircraft from excessive stresses. The positions of the wheels and supporting struts are designed to distribute the aircraft's weight and landing forces across specific attachment points in the structure. This design also accounts for the differences in loads carried by the main landing gear and the nose or tail landing gear, depending on the aircraft configuration. Proper load distribution helps reduce stress concentrations at attachment points and minimizes the possibility of deformation or cracks caused by repeated loading. Operating conditions, such as aircraft weight, landing speed, vertical descent rate, and runway surface condition, also influence the loads experienced by the landing gear. Therefore, engineering calculations and practical tests are conducted to evaluate the system's response under different conditions, including normal landings and landings involving higher loads within approved design limits. Computer simulations and structural tests are used to verify that the components can withstand the expected forces and comply with aviation safety requirements. Regular maintenance remains essential for ensuring the reliability of the landing gear. Maintenance procedures include inspecting hydraulic shock struts, checking for fluid leaks, examining the condition of tires, wheels, and brakes, and inspecting structural components for cracks, corrosion, or signs of fatigue. Early detection of defects helps reduce the risk of failures and improve operational safety. Aircraft landing gear is more than a collection of wheels and supporting struts; it is an integrated system that combines materials science, mechanics, hydraulics, and stress analysis. Continuous improvements in its design, materials, and testing techniques help aircraft land more safely, reduce the loads acting on their structures, and enhance operational efficiency and flight reliability. Lecturer Assistant Al-Buraq Haider Mohsen