PUB - Identification of wear progression due to variating operation modes of small high dynamic piston pumps used in frontline flight control application


Modern aircraft like the A380 use electro-hydrostatic actuators (EHAs) as backup in their flight control system. The future goal is to solely rely on EHAs for frontline flight control and thereby replacing the classic centralized system. However, as of now, the life expectancies of EHAs do not meet the requirements for frontline application. Difficult operation conditions result in wear in tribological contacts of the high dynamic axial piston pump. In this paper, an endurance test rig for analysing the impact of different operation modes as well as first results of long-term endurance test are presented. Lastly, the results are discussed and a conclusion is drawn.



Authors: Merkel,Amos; Duensing, Yannick; Schmitz, Katharina

To achieve the goal of a more electric aircraft current research investigates the substitution of the conventional control system with electro-hydrostatic actuators (EHA). The conventional, valve actuated pressure-constant hydraulic system consists of a centralized architecture, presenting high robustness and dynamic properties. While it meets all safety requirements, it bears some major disadvantages:

· Voluminous and heavy components

· Noisy operation

· Inefficiency

· Multiple installation of all components to achieve redundancy

· Necessity of highly skilled maintenance personal

Additionally, but not solely attributed to the flight control system, a flame-inhibiting, highly hazardous hydraulic fluid is used to lower the risk of explosion. This increases costs but more importantly increases the risk of physical harm of the maintenance personal. The inefficiency mainly results from the use of a pressure-constant hydraulic system, whose durability is proven ideal for the use in aviation, yet, the constant need to uphold significant power reserves in case of emergency like turbulences result in high idle power consumption