In an approved FTO the CFIs role is defined in App1a to JAR-FCL 1.055
CHIEF FLYING INSTRUCTOR (CFI)
15 The CFI shall be responsible for the supervision of flight and synthetic flight instructors and for the standardisation of all flight instruction and synthetic flight instruction. The CFI shall:
(a) hold the highest professional pilot licence related to the flying training courses conducted;
(b) hold the rating(s) related to the flying training courses conducted;
(c) hold a flight instructor rating for at least one of the types of aeroplane used on the course; and
(d) have completed 1 000 hours pilot-in-command flight time of which a minimum of 500 hours shall be on flying instructional duties related to the flying courses conducted of which 200 hours may be instrument ground time.
however in a non approved Facility or Flying Club there is no definition of a CFI so it can be whatever the management or holder wish to make it