I think the questions should be asked about why a GST is applied to "this service" which could be more accurately described as extortion.
If you charge a landing fee, one would logically assume that gives you the right to carry out whatever business you landed there to conduct.
It doesn't appear that fuel is even mentioned or needed.
And why would you entertain the notion of it being a good idea to address your concerns to the extortionist?
Isn't that a bit like reasoning with a bank robber instead of calling the police?
BTW. The airport was most probably paid for with taxpayers money and the "operator" who probably never put a cent into it, now sees fit to charge that same taxpayer again to use it, plus levy another fee and then add another tax.
rutan around is obviously at fault here, should have read the fine print.
Strewth!