Appointment of a patrolman to the Police Department is for a probationary period of one (1) year from the date of appointment. The probationary period of Sergeants, Lieutenants and Captains is six (6) months from the date of appointment. Continuation in the service is dependent upon the conduct of the appointee and his fitness to perform his duties. At the termination of the probationary period, if the conduct or capacity of the probationer has not been satisfactory, he shall be notified in writing that he will not receive absolute appointment, and his services shall be terminated by the Police Chief without a trial. The probationary period may be extended.