Due to the growing awareness of ecological threats, more and more attention is paid to the emission problem of undesirable substances into the atmosphere, the source of which is transport and energy. The impact of these factors on the environment can be reduced by using alternative fuels, which are non-fossil fuels, or by modifying these fuels to ensure lower emissions. One of the methods for reducing emissions from engines is the use of water fuel emulsion as fuel, which has a particularly positive effect on the emission of nitrogen oxides at high loads of drive and power units. An important issue affecting the possibility of using this fuel type is the impact of their use on the elements of the units in contact with fuel containing water and, optionally, an emulsifier. This paper presents inspection results of the hot section of a miniature gas turbine powered by Jet-A1 aviation fuel with the emulsifier addition. On the basis of these observations, the components of emulsion fuels were determined, which are the cause of the characteristic deposits occurring on the hot sections of the units after using emulsion fuels.