Oakape has it, it is indeed the 737 they operate there, I was working there for about 2 years. The approaches just aren't friendly to them without having the RNP like AirVan and AirNZ have at their disposal, lots of turn backs, well more than I'd probably consider average anywho. Have heard they are going to get approval for it soon though as it's costing them a lot of money obviously in delays and diversions!