Ensure that you have the latest version of the applicable airport, which contains compatibility fixes. This is recommended for all Orbx airports starting with EG... (except EGJA-Alderney, which is not within TrueEarth GB coverage area). Particularly if you have TrueEarth GB South installed, where most Orbx addon airports are located:
Open Orbx Central, Go to My Products, and select each airport individually. Click Verify files.