This paper focuses on the development of the concept of an active wireless sensor network (WSN) as a basis for improving the checkability of high-risk facilities in post-accident monitoring. The use of a drone system as WSN nodes provides a mobility network, the advantages of which are analyzed from the standpoint of improving the controllability and observability of the object in difficult post-accident conditions. The possibilities of renewing the resources of the mobile WSN, quick adaptation to the realities of training and reconfiguration as factors of ensuring high checkability of post-emergency objects are investigated. An analogy is drawn in the rating of checkability for digital circuits in critical systems and post-accident checkability of increased risk objects. The possibilities of active WSN, provided by its mobility, are analyzed.