I was recently doing a long haul flight from El Dorado International (airport of the capital of my country) And as I ascended with my heavy load to FL42, the autopilot started going all crazy, violently moving (while trying to align with my course). This got to such a crazy extent that my aircraft spun out of control and crashed.
I tried doing this flight again, thinking that it was pilot error, and the same thing happened, again at FL42. I was, however, able to descend to FL38 and there the problem got solved. I went to FL42 various times, and the same thing happened.
I just think it is an autopilot error because I had very relaxed 3 knots frontal wind. Also, I sadly do not have any footage of the incident.
How can I solve this? Is it because of the weight? Have you had the same problems?