Master Chief Petty Officer
From Starbase 900 Wiki
Master Chief Petty Officer is the ninth, and highest, enlisted rate (paygrade E-9) in Starfleet, just above Senior Chief Petty Officer. Master Chief Petty Officers are addressed as "Master Chief (last name)". They constitute the top 1% of the enlisted members of the maritime forces. Promotion to this rank carries requirements of time in service, superior evaluation scores, and selection by a board of master chiefs. Similarly, Senior Chief Petty Officers and Chief Petty Officers are chosen by selection boards. This rank can be abbreviated using MCPO.
This rank is equivalent to the Starfleet Marine rank of Sergeant Major.
Master Chief Petty Officers are generally considered to be the technical experts in their fields. They serve in commands of all sizes. Many Master Chiefs choose to enter the Command Master Chief Petty Officer program. If selected, a Master Chief receives additional leadership training and is assigned to a command as the Command Master Chief (CMC). The Command Master Chief is the senior enlisted person at a command and as such works as a liaison between the commanding officer and the enlisted ranks, serving as the senior enlisted leader. In this capacity, the CMC assists the commanding officer in issues of quality of life, discipline, training, and morale. If posted on a Starfleet vessel, the CMC is called the Chief Of the Boat or "COB".