Master chief petty officer of Starfleet

The Master Chief Petty Officer of Starfleet, abbreviated MCPOS, was the tenth enlisted rank and the highest non-commissioned officer rank in Starfleet.

Role
The MCPOS was appointed by the Commander-in-Chief of the Federation Starfleet to serve as a spokesperson to Starfleet Command on issues affecting enlisted personnel, and advise Command, the Commander, Starfleet, and the Chief of Starfleet Personnel.

The MCPOS was selected from the corps of master chief petty officers. Upon leaving the position they reverted to their previous grade.

History
In 2399 Miles O'Brien, former Chief of Operations for Deep Space 9, was appointed MCPOS by Fleet Admiral Sitak. His successor as C-in-C Starfleet, William T. Riker, retained him upon taking office in 2404.

Background
The rank of Master Chief Petty Officer of Starfleet is based on the.