[Octocat]

Cool. Simple modification, to add a random delay before failure:

    public override void OnAircraftTookOff(int missionNumber, string shortName, AiAircraft aircraft)
    {
        if (m_random.Next(1, 200 + 1) != 67)   // 0.5% chance of takeoff failure
        {            
           Timeout(m_random.Next(1, 60), ()=>  DoDamage(aircraft));
        }
    }

Also, in dynamic campaign, the chance of failure may depend on the aircraft aging, and damages in previous missions.