The warp field is most efficient in the tilted position, but for the purposes of routine checks and maintenance, you really wouldn't want the entire working environment in a tilted position. It's most logical to leave Voyager's nacelles down while not at warp so the floors and surfaces are level.
I think this 'logic' deserves to be added to the Variable Geometry Pylon page, yeah?
- I think the nacelles were left down when not at warp as a matter of course; while it might be convenient for maintenance, I'm not sure we should go as far as to say that was a design consideration. I think the primary design consideration for them was to address the reasoning for the Warp Speed Limit described in "Force of Nature". 31dot (talk) 22:21, January 8, 2013 (UTC)