Tail rotor cannot be repaired
There is no option to repair tail rotor. As of now for UH-1Y you can only repair following parts:
And Missiles seems to be out of place, repairing it doesn't repair anything.
Updated by Sa-Matra about 3 years ago
Screenshot, Scrap Metal in inventory:
Updated by kalelele about 3 years ago
You need rotor assembly kit to repair tail rotor.
Pretty hard to find though.