As they're going quite far and taking all that time with all their procedures, the aircraft is still climbing, correct?
Good one
Seriously the obstacles depicted on the departure charts,MSA in the 25 NM,would be sufficient info for the initial runway heading.
If your crews continue on tbe heading for more than 25 NM,it is that they are indeed rather slow and most importantly forgetting
to navigate,lost situational awareness...
...unless they do have supplementary obstacles charts and their heading is in the direction of their intended destination
