Perhaps the Pilot is very attached to the Film the hunt for red October...
Because During the Cold War this was an usual manoeuvre used by Russian submarine Captains to clear the baffles of the submarine. The manoeuvre was called Crazy Ivan.
Joking apart. If we are getting close to get a "traffic jam" at EDDV they use these manoeuvres:
Sometimes the northern A/C do a nearly perfect Omega, which is very close to your 360 turn.
One question: Did the captain the cycle at the same altitude or was he descending?
