My viggen also crash to the desktop.
When I finish flying the instant action in the Persian Gulf - Beachhead Interdiction - Rocket (if I remember the mission name correctly), every time when I land the Viggen, the game just crashes to the desktop. And I have my DCS beta repaired yesterday as this happened to me previously (I think is another instant action in the Persian Gulf).
and attaching the DCS log here.
Before the repair, I have encountered multiple crashes to desktop when I use Khasab Airport to create some simple flight plan in mission editor and just crashed to the desktop during loading couple of times in succession. dcs.zip