A method of sealing system design as part of the secondary air system for aircraft engines is proposed in this paper. It allows for the computation of the seal leakage flow rate, depending on the thermal state of the rotor and stator, and combines accounts of pressure loss, heat transfer, stress, and deformation conditions using the ther-mal-fluid-structural coupling method. As calculation examples were chosen for the HPC aft hub sealing system in the secondary air system of the NK-93 engine, the wall temperatures of the high-pressure system components predicted by the simulation are compared to those retrieved from a thermal model of the real engine, and the results are discussed with different radial clearances of the HPC aft hub seal influencing the leakage performance and flow direction of other neighbor seals in HPT.