Study of the Impact of Prolonged Operation on Residual Deformations in the Airframe Structure of an Aircraft

ABSTRACT Purpose The study aims to quantitatively assess the accumulation of residual deformations in the aircraft airframe during long-term operation, using the An-24 regional aircraft as a representative case. Methods Levelling data obtained during maintenance were statistically processed using regression and correlation analysis. Polynomial trend models were combined with probability distribution parameters (mean, standard deviation, skewness) to describe geometric deviations of wing control sections across different intervals of flight hours, service life, and landings. Results The analysis revealed that 25–32% of wing geometry variations are explained by accumulated flight hours, while the remaining deviations result from other operational factors such as hard landings, turbulence, and maintenance practices. Residual deformations manifested as systematic changes in wing incidence and dihedral angles, with probability estimates showing a nonlinear increase in the risk of exceeding permissible limits. Practical implications The findings improve monitoring of structural geometry through systematic levelling, enhance the reliability of residual life prediction, and support the development of preventive maintenance strategies aimed at ensuring long-term airworthiness and flight safety.