Analysis of Operating Loads on an Aircraft’s Vertical Stabilizer on the Basis of Recorded Data

Abstract

Structural health monitoring of aircraft is a necessary topic especially with aging fleets. In general, it means tracking the structural integrity and keeping the risk of not detecting hazardous cracks low. Traditionally fatigue analyses from collected data have been carried out in a flight-by-flight basis. However, simultaneous good-quality recordings of most relevant flight parameters with calculated fatigue damage synchronized with recordings enable a more thorough analysis. Using an adequate collection of time stamped flight parameter signals, this paper aims at analysing mileage sequences of loads on the horizontal stabilizer.
In order to ensure the safety of the supporting structure, software for detecting flight loads exceeding limits has been developed. The aim of this study was to analyse the completed data from flight recorder KAM-500. The task was to approximate passes of horizontal stabilizer’s loads by using a set of parameters recorded by the flight data recorder TESTER-U3t. For each of the analyses all available collections stored in the archives were used. Several measuring points on both left and right horizontal stabilizer of aircraft were considered.
The aim of this study was to determine the number of load cycles without knowing the distributions of load passes on the horizontal stabilizer. The algorithm is designed to detect the cycles in which the flight loads were significantly exceeding limits. Cycles with lower values were found to be insignificant in the context of further strength analysis of horizontal stabilizer. The effectiveness of the algorithm’s detection based on calculation is estimated to be 90-95 %.