Mmmm ....
AND I really think you'll find that the 'parabolic approach' isn't that at all ... but a well defined constant angle varying airspeed low(ish) rate of descent requiring minimum power changes till committing to the hover ...
Sometimes you might even have a crew member with their heads out the door checking and clearing your tail ... the communications for which will require time ... you don't want to be doing that stuff in a hurry ... THAT IS how incidents can occur ..
