Depends is it a B200 or a B300 Kingair.
The B300 Catpass Kingair will carry 2 pilots and 12 passengers, it would very cosy in the NT heat.
Pearl operate their Kingairs two crew on mining charters, and I suppose if the client wants two pilots that is what you supply.
Scarenorth had a contract at once stage in C402 that was to be flown two crew.