Greg Esres wrote:

It's unclear to me what "on the hook" for obstacle clearance means.
How can tower provide what it has no ability to provide?

Assuming no DP then as long as you climb in a normal fashion terrain
clearance is not a factor. If there is a DP, like the vector one we
have here at BIL, a minimum climb rate will be listed. I give you the
DP in the clearance and you will be issued a vector on departure.


The heading
they give you is presumed safe until departure can vector you. How
long can you fly the heading and be safe? Are there any criteria for
this?

Yes.



In his "Radar Services Terminated" article, Wally seems to indicate
that this is a gray area. He apparently only feels 100% comfortable
with a non-radar heading assignment when the area is 40:1 clear, as
indicated by the lack of an IFR departure procedure.

There are no nonradar headings. A nonradar tower or approach control
can not, by definition, vector.