In this paper precision of the system controlling delivery by a helicopter of a water capsule designed for extinguishing large scale fires is analysed. The analysis was performed using a numerical method of distribution propagation (the Monte Carlo method) supplemented with results of application of the uncertainty propagation method. In addition, the optimum conditions for the airdrop are determined to ensure achieving the maximum area covered by the water capsule with simultaneous preserving the precision level necessary for efficient fire extinguishing.

Three methods of estimating radii of spray droplets are discussed and results of their practical application in the case of explosively produced water spray are reported. Parameters of model radii distributions are fitted using the least squares method. Finally, the data obtained for a number of tests are used for estimating fraction of explosion energy used for pulverization of water in the process of explosive production of water-spray.