When an Gear gets removed after unit killed is it ready?

When a unit with attached gear is killed, the gear detaches and remains at the base. According to the established rulings, the gear returns to your base ready.

As stated in the FAQ:

"When the equipped unit dies, the equipment returns to your base ready, so you can pay the equip cost again to re-equip it."

This is consistent with the general rule that gear enters and exists at the base in a ready state unless otherwise specified (Rule 147.1).