HOW TO ACTIVATE MISSION - FLOATING BASE ATTACK?

[Guest Alexchamp]

Hello.

As I understand, mission Floating Attack base is activated/beginning since shotdown UFO SUB. Only here this mission is activated only in 50% cases approximately. Activating of mission Floating Attack of base it is possible to look in the file of Missions.dat or with help transmission resolver in game. If a mission was activated after shotdown UFO SUB, the survey ship will arrive exactly in 50 hours after shotdown/

Only not every succesful shotdown activates this mission. what can it depend? And that can influence on activating this mission?

why does it take place not always?