"Pilot mistakes are always possible no matter how good a pilot is.. "
True, but highly unlikely in this case, and let's not forget Luis, who, apart from being a nice guy was also a Mr Safety. If it was anything like that, it would rather be "the Human Factor" than "Pilot Error".
Uncommanded cyclic movements due to failed tarsyns are not impossible, neither are failed artificial horizons, and this is no reflection on the maintenance dept at Aerogulf, who are second to none, IMHO. They do an outstanding job.
Phil