A Line Officer is an officer (ensign, lieutenant j.g., lieutenant, lieutenant commander) from a non-command division (i.e. medical, operations, security, engineering, sciences) who wishes to be able to take command of the bridge during off-hours (Gamma-Shift) or in the event of an emergency situation when the regular command division officers are not available or dead. For example the Chief Medical Officer might wish to add Line Officer to his personnel file, and takes his Bridge Officer's Test, which enables him to sit in the captain's chair under certain circumstances. First, the officer must be trained in the use of all stations on the bridge, most especially Flight Control (Conn), Tactical, and Ops (Operations Management.) He must learn the basic functions of all departments of the shi