Consensus is this was a cold soak acceptance flight for an airplane just before customer delivery. Figuring fuel and maintenance costs at the fixed hourly rate just for an operator this flight was between $28,000 and $30,000
Sure wish I had $50,000,000+ laying around for a new G550.
A Gulfstream V (Five) is known simply as a G-5 or G-V.
flightaware link 
