What is located near the upper end of each shock strut for filling with hydraulic fluid?

The component located near the upper end of each shock strut for filling with hydraulic fluid is the fitting. This fitting serves as the connection point for introducing hydraulic fluid into the shock strut system, which is essential for maintaining the necessary pressure and functioning of the landing gear. During maintenance or inspections, hydraulic fluid may need to be added to ensure proper operation, and the fitting provides direct access for this purpose.

The fitting is specifically designed to withstand the pressures of the hydraulic system and allows for a secure connection to ensure that fluid does not leak during the filling process. Proper access to the fitting is crucial, as it enables technicians to perform necessary checks and maintenance on the hydraulic system effectively.

In contrast, an orifice valve is more often associated with controlling fluid flow or pressure within a hydraulic system, while a pressure gauge is used to monitor hydraulic system pressure but does not serve a direct purpose in filling the strut. A towing lug is a structural component used for towing the aircraft and does not have a function related to filling hydraulic fluid in the shock strut.