The exact identification of essential factors affecting the course of evasive manoeuvre, that has been computed to avoid a collision with moving obstacles, is necessary to ensure a safe passing by a moving obstacle. At the same time, during the evasive manoeuvre the pre-defined separation between the airplane and obstacles is required. The matter of presented work is defined as the analysis of influence of factors on execution of anti collision manoeuvre taking into account deformation of flight trajectory and changes of time histories of distance from the airplane to detected obstacles. Attention has been focused on internal interactions, resulting from the essential changes of the airplane’s behaviour. Discussion has been illustrated by selected results of computer simulations, executed for typical manoeuvres performed to avoid obstacles, while affected by adverse impacts of selected factors. The appropriate guidelines have been proposed, that should counteract these adverse effects on realisation of computed manoeuvre.