I will try loading up at BIRK later, the last time I got CTD directly at the airport but I also remember flying in a group flight towards here and also got a CTD in the air.
I also remember somebody reporting this issue. If you search BIRK on the forums, you will find more CTD instances at the airport or in the vicinity. It seems like an open issue.
Are using the free Orbx mesh for Iceland? If yes, maybe try without but I remember having CTD with and without it.