Q. Can diesel fuel be used in a jet engine?
A. Yes.
Q. Can diesel fuel be used in a jet engine-powered aircraft?
A. It depends.
For the ENGINE, the correct grades of fuel together with the alternate types of fuel (if any) that can be used, plus the time limits and mix ratio of alternate fuels, will be found in the engine maintenance manual.
However, this does NOT automatically mean that they can be used in the AIRCRAFT. For this, the correct grades of fuel together with the alternate types of fuel (if any) that can be used, plus the time limits and mix ratio of alternate fuels, will be found in the aircraft flight manual. These requirements, if different from those of the engine manufacturer, and they occasionally are, take precedence.