Ok, the only question in the back of my mind is the issue of lost comms given that assigned clearance -- If I'm flying rwy hdg but lost comms before actually getting those radar vectors.
So, let's say you're told, "Fly Rwy Heading, RV FIXIE, then AF, maintain 10,000, expect FL280 10 minutes after departure."
What do you do? That seems pretty easy, once you figure out that you're NORDO though, it may be impossible to join the ODP, or you may lose it after a few RVs, so I'd probably just go direct to FIXIE at this point. That's where ATC expects me to go. If you need the ODP you're probably not goign to be assigned RVs, but you could theoretically transition to it, but if you don't have that pulled up, or you're way off it, that it could be difficult. You might have to think on your feet a little bit.
A good example of this would be someplace I used to fly. If you're in KEUG and you're departing so late that the tower is closed (which used to be a thing, maybe they're open 24 hours now, I don't know), and you want to fly up to Portland and in an ancient caravan that doesn't have GPS, you might have a route something like this (which was my afternoon route for the year I worked there)
KEUG EUG V481 CVO V495 UBG KPDX, and let's say they clear you "On departure Fly runway heading, expect radar vectors to join V481 then as filed, climb and maintain 7,000, departure frequency is seattle center on 123.45, squawk 1234"
The idea being that you fly up to Newburg, if you're VMC you can break out and fly a visual to RW3, but if not you're VMC, you're still set up to do RVs to one of the 2 ILSs to the west or the east in Portland.
Let's say, for instance, that you takeoff to the North in Eugene, and immediately lose radio communications, what does that mean you do?
well, the ODP says at 1200 then make a left turn direct the EUG VOR and climb in the hold to get above MEA before continuing on course. I would suspect, that if you did this, all hell would break lose at center, because an airplane that was "kind of pointed in the direction they were supposed to go just went crazy ivan back to the VOR."
@NovemberEcho what say you?
I'd reckon that the "best" course of action in that case would be to turn to join V481 once you realized you were NORDO, and continue the climb, but I'm out of the game.