[1.0.3] Fuel saving between flights not working flawlessly

[daemotron]

 

Don't know if I understood the RA correctly, but I thought the actual fuel that was in the tanks at the end of last flight (when unloading the B733 or X-Plane) would be stored:

Quote

 

Version 1.0.3 introduces the following fixes:

• [...]
• Some data is now saved between flights, particularly fuel and MCP settings. 

 

However, I now get strange fuel values each time I load the B733 - no longer the standard 7,500 kgs from previous versions, but also neither the fuel I had in the tanks at end of last flight, nor the fuel I loaded for last flight. It seems to be 2268 kgs for the wing tanks each and 3506 kgs for the center tank now. I played a bit with monitoring IXEG_user_prefs.txt, to narrow it down. Here's what I found:

• When loading the 737 (quick start on x-plane launch), the fuel_amt_[1,2,3] variables are overwritten with the above given values (with 1 and 3 kept in sync).
• When doing a Gizmo reboot after having loaded the aircraft, fuel variables are re-set to the value stored in the last X-Plane session (maybe the amount that's really in the tanks? don't know where it takes this info from, could be read from IXEG_user_prefs.txt before overwriting it with the defaults given above). IXEG_user_prefs.txt is updated accordingly.
• Opening one of the IXEG dialogs directly after loading the aircraft (without reboot) shows correct values, but does not write them back to IXEG_user_prefs.txt
  • NB: the PREFLIGHT menu sometimes also shows the above given values from the file, but I couldn't figure out the conditions when it does so
• When changing the fuel via PREFLIGHT menu, the fuel variables are re-set to the new values and IXEG_user_prefs.txt is updated
• When changing the fuel via GROUND SERVICE menu, the fuel variables are not changed (i. e. IXEG_user_prefs.txt is not updated)
• Shutting down the APU (as probably the last fuel consumer being turned off in a flight cycle) does not trigger an update to IXEG_user_prefs.txt
• Shutting down an engine does not trigger an update to IXEG_user_prefs.txt
• Unloading the aircraft (by closing X-Plane) does not trigger an update to IXEG_user_prefs.txt

In consequence, when re-loading the B733 next time, the IXEG_user_prefs.txt either contains the fuel set through the PREFLIGHT menu (if done so after the last loading of the aircraft) or the seemingly random values posted above (since the IXEG_user_prefs.txt file is overwritten with them on each loading and the GND SERVICE menu doesn't trigger IXEG_user_prefs.txt  to be updated).

Therefore I'd recommend to update the fuel_amt variables in IXEG_user_prefs.txt also on those events:

• PREFLIGHT MENU on close (even if fuel was not updated - say I just opened to check and was happy with the values there, then I still have 2268/3506/2268 in IXEG_user_prefs.txt and a bad surprise next time I load the aircraft)
• GND SERVICE MENU end of refuelling
• GND SERVICE MENU on close (same rationale as for PREFLIGHT MENU)
• on engine shutdown (taking the values in the tanks)
• on APU shutdown (usually the last fuel consumer being shut down on a normal flight cycle)

 

[EDIT]

P. S: I somehow forgot the scenario "open X-Plane with the B733 and close it again without doing anything" - that would again write 2268/3506/2268 into IXEG_user_prefs.txt, so bad luck on next start. Not sure how to catch this one (I'm no expert, but most probably there isn't an "on_exit" event - and for sure non for a hard CTD), so probably the best solution would be to enhance initialisation routines to write back the actually correct fuel setting into IXEG_user_prefs.txt before taking any other action.

Edited May 8, 2016 by daemotron

[Litjan]

Wow, thanks for putting all this research into this!

I think the intended behaviour for the fuel is "always start with the amount the user sets up once" - so the guy that always wants to start with 5000kgs doesn´t have to drag the sliders everytime he starts X-Plane. Setting the "current fuel on exit" would defeat that purpose...

I personally think that we might want to revert to the old "fixed" system for the fuel - and maybe tell users how to edit the value in the prefs.txt...

Jan

[daemotron]

4 hours ago, Litjan said:

I think the intended behaviour for the fuel is "always start with the amount the user sets up once" - so the guy that always wants to start with 5000kgs doesn´t have to drag the sliders everytime he starts X-Plane. Setting the "current fuel on exit" would defeat that purpose...

Hm, if that's the intended behaviour, it should work when overwriting the fuel prefs during initialisation is deactivated - then the preflight menu alone will set the prefs, and they're not changed through anything else.

[Litjan]

Right - but later on they need to be overwritten again (when fuel is being used or changed through the GROUND SERVICES menu). So it ´s not completely trivial... We see different behaviour when there is heavy loading and initialization (scenery, plugins, etc) - and no issues if load is light. It´s hard to reproduce. But we have some ideas...

Jan