Petty Officer Third Class

Petty Officer Third Class is the lowest Starfleet non-commissioned officer rate. Petty Officers Third Class generally serve as relief personnel to another post, such as transporter operator. Petty Officers are specialists within a field, known as their rating. A petty officer may be addressed by their rating, such as Hospital Corpsman Third Class, or Torpedoman's Mate Third Class, as well as by the generic title of Petty Officer. A PO3 takes a fleet-wide exam for advancement to Petty Officer Second Class.