As Principal Flute you would take day to day responsibility for leading the section, play the leading role in the recruitment of new players and select those who are engaged as extras.

The Orchestra’s contract guarantees a minimum of 430 sessions or calls in a year. A session will be not more than 3 hours and often less (e.g. a concert which are normally 2 hours). This is also the maximum that you will be required to undertake without your agreement and additional pay. There are checks and balances in place to prevent overwork such as a maximum number of sessions in a day (2), a week (12) and a free day structure which equates to 2 days a week free plus statutory holidays etc. Up to 10% of sessions may be taken off, without pay, by agreement with the Concerts Director. The Orchestra break for 5 weeks paid holiday in the summer, usually in one period. 

See further details at the link below.