Welcome to FT!
I don't believe you'll have much luck due to the requirement for ASIC's to be issued for anyone working in secure areas.
I did look into this back in the 90's when I was interested in sitting in Row 00 for a job, but QF and AN didn't offer anything back then.
Perhaps contact head office in Mascot and ask them for details.
Just saw this though:
http://www.careers.qantas.com.au/App...Questions.aspx
From this:
Q. Does Qantas Engineering offer work experience?
A. Unfortunately due to safety and security requirements we are unable to provide work experience opportunities in operational areas of our business.
It mentions Qantas Engineering, but the 'operational areas of our business' may be a little bit of a bad sign
Let us know if you have success though! Try TT and DJ too. Never know!