So you really mean $50K ($47K Aus)after tax first year,2015
$101K-$50K=$51K nzd ($47K Aus)for your type rating bonded for 3 years to Vanz
It is not similar to salary sacrifice, there is no such thing in NZ. In australia expenses come before tax in Nz they come after.
Auckland is rather a expensive city, especially with family.