Petty Officer Third Class is the fourth enlisted rank in Starfleet, just above Crewman and below Petty Officer Second Class, and is the lowest form of non-commissioned officer, equivalent to a Corporal in the Marines or Senior Airman in the Starfighter Corps.
Unlike the Crewman and lower ranks, advancement to Petty Officer Third Class is not automatic given time in service, but is also contingent on performance evaluations by their superiors and rate examinations (test of specialty knowledge), except for certain technical ratings which carry automatic advancement to PO3, after successful completion of the rating's "A" school and fufillment of time in rate requirements. The advancement cycle is currently every 6 months. Only a certain number of billets (job openings for this rank) open up biannually and all Crewmen compete. The top scorers are chosen for advancement, but only in sufficient quantities to fill the billets available.
Petty Officers serve a dual role as both technical experts and as leaders. Unlike the sailors below them, there is no such thing as an "undesignated Petty Officer." Every petty officer has both a rate (rank) and rating (job, similar to an MOS in other branches). A petty officer's full title is a combination of the two. Thus, a Petty Officer Third Class who has the rating of Fire Control Techinican is called a Fire Control Technician Third Class. The term petty officer is, then, only used in abstract, the general sense, when referring to a group of petty officers of different ratings, or when the petty officer's rating is unknown.
Each rating has an official abbreviation, such as FT for Fire Control Techinican, ST for Sensor Technician, or ET for Electronics Technician. When combined with the petty officer level, this gives the short-hand for the petty officer's rank, such as FT3 for Fire Control Technician Third Class. It is common practice to refer to the petty officer by this short hand in all but the most formal correspondence (such as printing and inscription on awards). Often, the petty officer is just referred to by the short hand designation, without using the surname. Thus FT3 Shearer would just be called FT3.
- ST3 Tarah
|Enlisted ranks||Non-commissioned officer ranks||Etc||Commissioned ranks||Flag ranks|
|Federation Marine Corps||Pvt||PFC||LCpl||Cpl||Sgt||SSgt||GySgt||MSgt|
|WO||2nd Lt||1st Lt||Capt||Maj||LtCol||Col||BGen||MajGen||LtGen||Gen||GenCorps
|Klingon ground troops||Bekk2||Bekk1||Cpl||Sgt||MSgt||SgtMaj||2nd Lt||1st Lt||Capt||Maj||LtCol||Col||Brig||LtGen||Gen|
|Romulan Star Navy||UHL||(unknown)||SLt||Lt||Cent||SCdr||Cdr||Adm|
|Tal Shiar||2nd Lt||1st Lt||Capt||Maj||Col||Gen|