Is jet fuel the only thing planes can run on?

Answer 1

Sometimes yes, sometimes no, sometimes maybe.

Turbine powered aircraft require jet fuel, which is chemically the same thing as diesel fuel and kerosene, but much more highly refined, and with a few additives to mitigate dangers from icing or other contaminants. There is no reason you couldn't run a jet engine on diesel fuel, just don't let the FAA catch you.

Piston-engined aircraft do not run on jet fuel. They run on whats called "av-gas" (short for aviation gasoline.) Av-gas is very similar to automotive gasoline with the exception that it is generally 100 octane and, at the present, is still leaded. (It should be noted that the FAA is currently working to phase out lead additives in avgas.) Many piston-engined aircraft can also run on automotive gasoline, although most pilots still prefer to use avgas as it is said to reduce the risk of carburetor icing, detonation and vacuum lock. Av-gas would work in your automobile, but would result in smoky smelly exhaust as well as eventual fouling of the spark plugs from carbon buildup.

In a pinch, jet-engined aircraft can be run on av-gas, with severely reduced performance and extremely reduced range. Once again, dont let the FAA (or your mechanic) catch you doing this, but it beats being stranded.

If a piston-engined aircraft is run on jet fuel however, it will result in engine failure. Generally the fuel lines will have just enough av-gas in them for taxi and takeoff and the jet fuel will hit the engine (and kill it) right after takeoff, when an engine failure is most deadly. For this reason aircraft fuel types are treated with deadly seriousness at airports and most jet fuel pumps have special nozzles which will not fit into the smaller fuel receptacle of a piston-engined aircraft.

Some aircraft manufacturers are now making diesel-powered airplanes. These are piston-engined aircraft which run on jet fuel. This is done for reasons of fuel economy as well as monetary economy as jet fuel is often cheaper than avgas. However, like any diesel, attempting to run them on gasoline (or avgas) will damage the engine and result in engine failure

Some aircraft manufacturers and airlines are experimenting with using bio-fuels. Since jet fuel is so similar to jet fuel, bio-jet fuel can be made using the same process that is used to make bio-diesel. This has only been done on a test basis, and is not yet approved for use with passenger aircraft. Hydrogen fuel cell technology is also being experimented with, but with limited results as hydrogen technology does not perform well at low temperatures.