There was a certain instructor on the Bucc OCU at Honington (1971) who introduced all new navs to the loop in a Buccaneer on their FAM 1 sortie - so he must have done it more than once and survived!
It went like this:
Pilot: Right Foldie, I'm now going to show you a loop in a Buccaneer!
Baby Nav (thinking catch question this): A loop is not cleared in the Release to Service! (thinking gotcha - ya can't catch me).
Pilot: Shut up, hold on, give me the heights and speeds on the way up AND on the way down!
I recall we entered at 5000ft and bottomed about 2000ft - the rest was a complete blur but I passed the sortie and subsequently, the course!
Foldie