Markoz wrote on Jan 15^th, 2019 at 1:18am:

If you finished a flight, the fuel remaining at the end of your previous flight would be all you have for your next flight. Even loading a different 757 III model will not reset the fuel, so you need to redo the fuel after completing a flight. I'm not sure if, by what you are saying, you think that changing/resetting a panel state will reset the fuel. It doesn't. It only resets the panel state. If none of therse is the case, I have no idea why it tumbled out of the sky. This has never happened to me. I have stalled after takeoff though, but that was because of pilot (me) error!

Let me clarify. It was not a flight carrying on from a flight just ended. It was a fresh flight that loads the default 'engines running, ready to fly mode.

All I did was shut the engines down power up by the EP and then run a normal flight except without going through all the CDU set up rigmarole just for fun on a very short flight.

I did not need any LNAV or VNAV because I already had a map to follow whatever Heading I chose.

And everything was running fine, except when climbing to around 20000ft, all of a sudden the engines cut out and the aircraft just plummeted out of the sky.