I have 3 Firebird Phantoms, one is just a parts plane now but the other two fly just fine. All 3 have had the "clasic" tail spar break problem and I've tried lots of different repair methods. The one that I'm currently using and having success with on both planes is:

1.) cut a 3" piece of 1/4 x .014 round aluminum tube. (I got a 1 foot piece at the LHS for $0.99 )
2.) shave a hole in the middle of it with a razor knife.
3.) elongate the hole toward both ends by carveing with the razor knife(trying not to widen it very much) until it's about 3/4" long.
4.) slide a coffee sturring straw through the hole and out one end.(this is for the control rods and antena to pass through and protect them from the glue.)
5.) insert the control rods and antena through the straw and out the top, and dry fit everything, test to make sure the rods move smothly... if not you may need to make the hole a bit longer so that the bend in the rods is less.
6.) use an expanding glue (I love Gorilla Glue, follow the directions) as the glue cures it expands and tightens the grip between the inner carbon tube and the outer aluminum tube.

You just can't beat the economics of this plane... $55.00 RTF... it's worth learning how to repair it. IMO

Thank you
Shawn