Originally Posted by
jrl767
that sounds about right; as I said, he got a VFR departure clearance to an initial altitude of 8000
from my long-ago days at Boeing Flight Test (and even longer-ago FAA ground school), I know that any flight plan at or above 18000 *has to be* IFR, but I believe pilots *can* file IFR for lower altitudes; that said, though, I have no idea of any specific language that pertains to transitioning from a VFR departure to IFR enroute
correct - you must be on an IFR clearance once you reach FL180. You can depart VFR, then pick up your IFR clearance once airborne. Pretty rare at the airlines but it is permissible if the specific Ops Specs (rules for that airline) allow it.