Apartment Balcony Safety

Hi there -
What would be the best way to protect my Kitty at a 3rd floor apartment? I am moving to LA, and would love to give her the opportunity to enjoy the balcony, but also need to make sure she is safe... Especially because I will be traveling often for my job, and I want to make sure she is safe with me or the the Sitter (My very good friend will move in every time I travel)... Any Ideas? Does Purr.... fect fence work on hard floor, or can only be installed on the grass?

Thanks!

Im not sure how to enclose it, but I would not let her out there, unless it was enclosed. Cats have fallen/jumped before from something as innocent as going after a bird.

The Mgr may not let you enclose it.
There are so many cats that fall and die from balconys so i would not let her out there.
Some apartments do not allow anything to be modified.