Hi Mike,

I'm a bit confused by the double "a" marking in your pack but it is basically an old 4-cell 110mAh NiCd pack.

These are available many places. Balsa Products sells one here but the dimensions are not listed so you may want to call them.

Additionally, Batteries America sells these packs for another source.

Today, most of the NiCd packs can be replaced by NiMH packs to double the flight duration using a similar size and weight pack.

One example is the 170mAh NiMH pack seen here.

You may also want to try a local hobby shop (LHS) to show them your pack for replacement.

Good luck!