You decide the solution to a problem when you choose the person tasked to fix it. Setting the chief of personnel to sort out rostering is bound to lead to a manual solution with even more human resources, which there is no need for since the computerised rostering system has the ability of a nearly fully automated process provided you utilize all of it's features including long term requirements, analytics and crew holliday preference selection adjusted to availability.
Sometime companies that are in part highly regulated forget to adequately train the areas of the operation that is not. Internal training might in some cases be do the job, but one can't expect internal trainers to have full knowledge about all newly developed features in an outside sourced system without regular updates from the third party.