Grades PK-12. 4.1.1: A school is comprised of a team of certificated professionals working toward the educational excellence of all students who attend the school. The principal, with the input of the bargaining unit members assigned to the school, determines the needs of the school. The principal shall determine the schedule and make necessary assignments of schedules and supervision duties which will ensure the safety of students attending the school. The duty day of all bargaining unit members shall include as much time as is necessary to fulfill professional duties to facilitate the educational program. Duties shall be assigned on an equitable basis. For grades PK-5, assignable duties include supervision of students during recess and during student drop-off and pick-up times. A regular classroom teacher in grades six (6) to twelve (12) shall be assigned supervision duty only as provided in section 4.2.