ORIGINAL: tschuy
The thing to realize is that you still will have some gas in the propane bottle while your flying your jet. A potential problem and fuel source for a fire as stated in the owners manual that came with my engine..
FYI, JetCats can be set to purge the remaining propane/butane gas after start and before flight, so you fly around empty if you want, not sure if any other turbines do that or not.