Once I went into Blue Hell, I noticed that my plane was spinning out of control. Very out of control. Slowed down, started to pull down at an attempt to stop spinning. Succeeded, and explored Blue Hell. Eventually left by simply pulling up and going back through the way I came.
I got to blue hell by ejecting from my plane just before it hit the ground in the mountains, I spawned in a drop container and used a boat to sail around before leaving by going through a "wall", (baisicly the ground of the map) near the sea.