Thank you for your answer. I've tried to implement this but without success yet, but maybe I'm doing it wrong. Basically what I'm trying to accomplish in my custom mission is to set a plane on my six, at my altitude exactly 500 m behind me. I got killed so often that way online that I would like to practice escape from such situation.
Right now my mission looks almost like it should be except this initial speed of 'bandit' plane that equals mine and in result it's speed of approach is 1-5 km more than mine. I would like it to be at least 50-100 km more to make it more real.