I know it's not Africa, but look at this - Aer Lingus
31 May 2006 Aer Lingus to leave oneworld -------------------------------------------------------------------------------- AER Lingus has announced its intention to leave the oneworld alliance, but retain bilaterial links with some of oneworld’s member airlines. In a statement, oneworld says Aer Lingus’ strategy has changed fundamentally sinced it joined the alliance six years ago and is no longer convergent with oneworld’s. Oneworld adds that while oneworld’s target market is the multi-sector, premium, frequent international traveller, Aer Lingus has repositioned itself as a low-cost carrier.

Apparently EI were not gaining any significant benefits from the alliance. Also with JL, RJ and MA joining oneworld in early 2007 all oneworld members would have to have forked out US$2 million on a systems upgrade, which EI saw as an unjustifiable expense apparently. Still holding out for a DUB-CPT service sometime soon, maybe when their new A330s arrive....