Learning Turkish before joining THY, what level actually helps?

For foreigners considering THY. You can join with none, but here is my honest experience: A2 by the time I arrived made the crew room bearable, B1 after six months made Istanbul feel like home. Announcements are done in Turkish by Turkish crew, you do the English ones. Landlords, the crew bus, the doctor: Turkish. If you have six months before joining, do a course.