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Method to determine internal leakage of aircraft's hydraulic servo

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Original languageEnglish
Title of host publication12th World Congress on Engineering Asset Management & 13th International Conference on Vibration Engineering and Technology of Machinery
Subtitle of host publication(WCEAM 2017) 2-4, August 2017, Brisbane, Australia.
EditorsJ. Mathew, C. W. Lim, L. Ma, D. Sands, M. E. Cholette, P. Borghesani
Number of pages7
ISBN (Electronic)978-3-319-95711-1
Publication statusPublished - 2018
Publication typeA4 Article in a conference publication
EventWorld Congress on Engineering Asset Management -
Duration: 1 Jan 1900 → …

Publication series

NameLecture Notes in Mechanical Engineering
ISSN (Electronic)2195-4356


ConferenceWorld Congress on Engineering Asset Management
Period1/01/00 → …


This paper addresses a method to determine possible internal hydraulic leak of airplane control servo. Internal hydraulic leakage is difficult to perceive due the leak doesn’t have any visible evidence outside the control servo. Leaking happens past the hydraulic piston or through faulty control valves. Such leaking can have serious consequences due servo’s decreased capacity and force especially situations where all the aerodynamic force of control surface is needed to maintain the ability to control the airplane. This kind of hidden failure can advance unobserved because decreased capacity of the servo can be enough to keep the airplane in control during normal flight conditions. However, in heavy flight manoeuvres such as aerobatics, the decreased rate of control surface’s angular velocity can lead to in-flight loss of control.
One relevant problem is how to find out when inner leakage is so severe, that it endangers safety of the airplane. To solve this kind of problem, a detailed quantitative model has been built. This model utilizes recorded in-flight process data and aircraft’s aerodynamical characteristics to determine condition of the control servo.


  • airplane, hydraulic control servo, hydraulic cylinder, inner leakage

Publication forum classification

Field of science, Statistics Finland