I suspect that the real problem is the board and that the CASA board either a) don't know how to recognise a good CEO or b) a good one won't work with them.
If I were Warren Truss, I'd look at AMSA which causes no grief and generally seems pretty competent and compare it with CASA which is frequently in the press for stuff ups and is generally a major drama. I'd be looking to replicate the good bits of AMSA in CASA.
Consider the two boards:
CASA: 4 directors + CEO. Chairman: career public servant. Background in foreign affairs / public policy. Board members: ex Boeing CEO & 2 lawyers.
AMSA: 8 directors + CEO. Chairman: Business qualified with a career managing ports. Board members: 1 x shipping, 1 x fishing, 1 x lawyer, 1 x investment banking, 1 x Dept Transport policy public servant, 1 x retired sea captain, 1 x fisherman.
Overall, CASA is characterised by lawyers & public servants whereas AMSA is characterised by a diverse range of industry expertise.
Is it any surprise that CASA's main activity is rewriting regulations & prosecuting people?