Proving Dynamic Properties in an Aerospace Application

In this paper we give an exposition to an ongoing research eeort in cooperation with aerospace industries in Sweden. We report on an application of formal veriication techniques on a landing gear system. This system consists of actuating hydromechanic and electromechanic hardware, and of controlling software components. We emphasize the need for modelling techniques and languages covering the whole spectrum from informal engineering documents, to hybrid mathematical models. In this modelling process we give as much weight to the physical environment as to the controlling software. We show the application of two veriication methods for proving safety and timeliness properties of the closed loop system; rst, using the proof system of extended duration calculus, and second by symbolic model checking.