Hydraulic fluid and the systems that govern it in aircraft are key to ensuring flight safety. The EU-funded project 'Smart maintenance of aviation hydraulic fluid using an onboard monitoring and reconditioning system' (Superskysense) worked on developing a powerful automated maintenance system for aviation hydraulic fluids. It proposed an autonomous onboard system to monitor and manipulate hydraulic fluid as needed, prolonging its life and avoiding damage due to fluid degradation. Generally hydraulic fluid suffers from unpredictable behaviour so it must be tested regularly. However, testing is considered difficult and costly. It is therefore typically tested less than once a year, which leaves plenty of time for issues to develop. The new system would reduce downtime, decrease environmental impact, minimise costs and increase safety of hydraulic systems. With this in mind, the project team designed an intelligent multisensory onboard system to monitor and evaluate hydraulic fluid. It also looked at specific ways to combat fluid degradation and extend its usefulness indefinitely. Superskysense produced three prototypes to undergo different kinds of tests including vibration testing and endurance/fatigue testing. The system passed the vibration test successfully, having withstood the 5,000 pressure cycles and electronic cycles it was exposed to. It also passed the fatigue and endurance tests successfully, noting some minor issues which could be optimised. Functional fatigue testing was performed at different temperatures and was also considered successful, except for the electrical capacitance and reconditioning tests which were inconclusive. Success of the tests and slight modifications needed take the aviation research community one step closer to manufacturing a superior hydraulics maintenance system. Once exploited, this technology will bring with it lower maintenance costs and safer skies.