You haven't attached anything. However, it's normal that jetways and other objects would reduce in complexity after a certain viewing distance. That's called LOD optimization, and it's a good thing, to keep the fps up.
Note that, on top of being related to actual distance, the LOD is also dependent on the zoom settings so, if you fly with too wide zoom settings, such as 0.50 or less, details will disappear sooner. The scenery is optimized to be used with a zoom setting of 0.70, which is known to be the most realistic setting.