If it is not possible to get a departure clearance from ATC, and you absolutely must take off from an uncontrolled airport in IMC, what’s the best and safest way for you to depart?
A) Maintain at least a 500 foot per minute climb
B) Climb straight ahead and do not make any turn until in VMC conditions
C) Fly the approach in reverse
D) Don’t; walk!
Arguably, it might be choice C: Simply flying the approach in reverse would work best, because it would best guarantee obstacle clearance. Of course, somehow prior to entering into controlled airspace, you’d better let ATC know about it, and they would determine exactly what route they would want you to fly. But out in the middle of nowhere (assuming the field had an approach), this would be the best way to go. These sorts of impromptu (and even “pop up” clearances) do take a little intestinal fortitude. (Note that there are airports with approach procedures but no departure procedure.) Yes, doing this reverse approach thing is legal, even if the airport in class G underlies class E, but it could be non-habit forming…