The kinetics of fatigue crack growth in VT6 titanium alloy (α + β structure) un-der external quasi-random cyclic loading of various types with asymmetry R 0 and 0.5 was investigated. The results of fatigue crack growth and FCGR (Fatigue Crack Growth Rate) for different structural states of the alloy (globular and lamellar microstructure) are presented. It is noted that the crack growth kinetics largely depends on the type of loading amplitude sequences as well as on the alloy structure. In the globular structure, the crack grows faster than in the lamellar structure from 1.6 to 4 times depending on the loading type. It is proposed to estimate irregular loading using the parameter V. A model for estimating the crack growth duration based on the nature of the random force impact and the study of the fracture features of the investigated alloy has been developed. A comparison of calculated and experimental data is carried out, which showed a good correlation.