Detection of Sensor Detachment in Aircraft Engines Using Vibration Signals

Sensor detachment are very common in aeronautic applications wherein equipment operate under very high power and severe environmental conditions. The effect of such defects is detrimental for health monitoring which requires an accurate vibration measure and, therefore, their detection is of high practical importance. This paper investigates the effect of accelerometer faults on the measured vibrations and proposes a two-step methodology to detect their presence using the signal itself. The first step consists of a prewhitening step which has for aim to remove the deterministic part of the signal. The second designs a relevant asymmetry indicator, namely the outlier counter indicator, able to detect the presence of an attachment fault. The efficiency of the proposed methodology is demonstrated on real vibration signals acquired from an aircraft engine gearbox in healthy and faulty sensor cases.