I cannot believe that an operator as large as Skippers runs without a roster?!?!?!?!?! Even the shyster twits I worked for up north managed a roster (introduced after inumerable cockups with pilot duty). Even without any assisting software, it is not rocket science. As you say Stick pusher, a fair amount of mining charter in fact follows a pattern that can be allowed for. I don't know if Skippers have this complication, but we had pilots flying multiple types, however with a bit of thinking (ie model the problem), all the eventualities could be catered for. That is, no servicable aircraft was unable to be crewed on a given day, thus no ad hoc charter had to be turned away. Pilots knew what days they had off and this improved morale quite a bit. The owner/managers however couldn't understand how it worked and believed somehow that the pilots would work less!!! (same number of pilots as pre roster).
That Skippers apparently can't even attain that level of organisational competence seems strange. I mean with DHC8s and EMB120s along with M23s and C441s their maintenance scheduling would have to be fairly organised and efficient one would think or it would all come undone in a short space of time.
