Warrant Officer 1st Class is the first warrant officer rank, below Warrant Officer 2nd Class. Like other warrant officers, these individuals started out as enlisted personnel, and now serve as specialized commissioned officers highly trained in one area (like engineering). Unlike regular commissioned officer who underwent training at Starfleet Academy, warrant officers gained their rank through years of service and obtained their authority through warrant from the President of the United Federation of Planets. Chief Warrant Officers are capable of serving in any junior or senior officer post except Commanding Officer or Executive Officer.