At present, modeling of airborne systems of aircrafts is carried out with the use of various software complexes, both in three-dimensional formulation (computational fluid dynamics. software complexes LOGOS, ANYS CFX, Fluent, Star CCM +) and in a one-dimensional setting (SimInTech, LMS Amesim, Easy 5 etc). Simulation is usually carried out in various software complexes, for example, the environment control system can be calculated separately in SimInTech, the flight system is developed in Matlab Simulink, and the components of aircraft systems are considered using CFD codes. Sometimes, also, calculations are carried out in software complexes of its own development (for most aviation enterprises). Thus, often we need to calculate complex, branched systems, taking into account the relationship between different systems i.e. there is a need to create a single integrated model on one platform. The software complex must combine various models of systems (environment control system, fuel system, ideal gas systems, power supply system, etc.), and also allow interaction (data exchange) with the software complex of computational hydrodynamics. To solve similar problems, special software packages are used for joint hydraulic and thermal calculations that allow replacing real complex systems and structures with structural diagrams of the corresponding mathematical models. One such software package is the Russian software SimInTech. The program complex SiminTech refers to CAD systems of logicaldynamic systems described in input-output relations and has sufficient functionality for solving design and optimization tasks for given characteristics at all stages of the system life cycle. The paper considers the concept of creating a complex mathematical model of an aircraft, including the main onboard systems (environment control system. fuel system, power supply system, ideal gas system. hydraulic system, ice-protection system, chassis system). The complex model of airborne aircraft systems will allow solving not only design tasks not only at the stage of conceptual design. but also subsequent phases of the life cycle of aircraft; including simulation of failures and certification.