Problem with fuel loading overshooting Instructor Page Preselect value

[Will]

Hello all, I am away from home so I can't upload the situ in question, but I can describe the behavior and I'm hoping you can tell me were to look to locate the problem.

The problem is that the automatic fuel loading goes to the PREVIOUS value entered into the "Preselect" field on Instructor > Situation > Service, not the CURRENT value.

Here's how it happens. In the fuel Preselect window, I can enter a desired fuel quantity, say 200,000 lbs, and hit start. Instead of 200,000 lbs though, the Preselect number on the EICAS fuel synoptic shows the max quantity possible, and the fuel robot overshoots the 200,000 on the Instructor Page and tops off the tanks so that the quantity equals the EICAS Preselect value, not the Instructor page Preselect value. Then, if I manually set the fuel quantity back down to 50,000 lbs and put 150,000 lbs into the fuel Preselect window on the Instructor Page and hit Start, now the fuel synoptic on the EICAS shows the previously requested 200,000 lbs and that's what the robot fills the tanks to, overshooting the 150,000 lbs currently on the Instructor Page. If I repeat the previous steps, lowering the fuel quantity back to 50,000 lbs, and then putting a new value, say 300,000 lbs into the Instructor Page Preselect window and hitting Start, now the EICAS shows 150,000 lbs and that's where the fuel loading stops.

So you see, the fuel robot always follows the fuel synoptic on the EICAS, but the fuel synoptic on the EICAS is not the CURRENT value on the Instructor Page, but the PREVIOUSLY entered value. The EICAS Preselect value always lags one step behind what's currently entered on the Instructor Page.

I'm guessing this is because my situ is corrupted, because I don't see this behavior when I load the Basic 001 situ. (In Basic 001, it works as advertised; the Instructor Page Preselect and the EICAS fuel synoptic Preselect always agree.)

I know I can create new derivative situs from Basic 001 and thus "fix" the problem, but I'm also curious about what the underlying cause is here, and, if I'm correct that my situ is corrupted, then where along the way that happened.

As I said, I can't upload the actual situ until Tuesday when I get back home, but if there's a hint as to where I should start looking, maybe I won't have to upload it at all.

Thanks.

[Hardy Heinlin]

Hello Will,

didn't you mention this some years ago, and we were unable to reproduce this effect?

I guess you got it from a very old alpha test situ. Just use a situ that was saved with an official PSX version.


Regards,

|-|ardy

[Will]

Correct, I did mention this a few years ago, but I couldn't find the old post on the forum to update it.

I'm only posting about it again now because after all this time, only now did I finally find a way to reliably reproduce the issue. (I don't start many flights from that old Cold & Dark situ.)

If it's an artifact of an older iteration of PSX, then no point in troubleshooting.

[Will]

Hardy, here is a situ that reproduces the problem. I took your thoughts about it being an old situ from the alpha testing into consideration, but the linked situ was derived this morning from Basic 000 - Cold and dark cockpit.

To see the issue, go to Instructor > Situation > Service. You'll see the Preselect value defaults to 359413 lbs. Change that to 100000 lbs and hit Start.

Now look at the EICAS fuel synoptic. The displayed preselect value is 359.4... and indeed, that's how much fuel will be uploaded if you let the fuel truck do its thing.

https://www.dropbox.com/s/83pwe3gp75rxub9/Fuel%20Overrun.situ?dl=0

(Please let me know if there are any troubles with the link.)

[Hardy Heinlin]

My robot stops at 100000. At that point my EICAS ist at ca. 96000. The EICAS value keeps rising and after some minutes it reaches 100000 and stops.

That's easy to explain.

It's not a bug; it happens in real life as well.

What you see on the EICAS is the value from the totalizer fuel system. This value rises more slowly than the true quantity; the system incorporates an artificial "inertia" to avoid prompt fluctuations of the sensed fuel level data when the aircraft is changing its attitude or speed. It takes several minutes until the displayed value is equal to the true quantity.

There is a button on the Instructor: "Reset lag". That skips the delay.


Regards,

|-|ardy

[Will]

I'm not talking about the Total Fuel display, I'm talking about the Preselect display. The total fuel lags, yes, and can be reset, but the Preselect display shows how much the fuel truck is going to deliver, right?

Looking at the Instructor > Situation > Service, you'll see that you can put 100000 into Preselect, and hit Start, but the EICAS Preselect displays not 100.0, but 359.4. Then after all the fuel is delivered, the aircraft now has 359,413 lbs on board, not the 100,000 lbs requested from the fuel truck.

You can verify this by watching the fuel load increase on the Instructor page.

[Hardy Heinlin]

I start your situ.
On the Instructor I preselect 100000 and start.
My lower EICAS indicates TOTAL FUEL 38.0 and PRESELECT 100.0
At 100000 the robot stops correctly as expected.
My lower EICAS indicates TOTAL FUEL ca. 96.0 and keeps rising.
After some minutes my lower EICAS indicates TOTAL FUEL 100.0 and stops rising.

[Will]

I start my situ.
On the Instructor I preselect 100000 and start.
My lower EICAS indicates TOTAL FUEL 38.0 and PRESELECT 359.4
At 100000 the robot does not stop correctly as expected.

I have no idea how this could be a local problem (to my machine), but apparently it somehow is. I can make a screenshot for you later... the Instructor Page shows a Preselect of 100000, while the EICAS shows a preselect of 359.4. And the robot always follows what is in the EICAS, and ignores the instructor page Preselect.

It happens every time with this situ.

[Avi]

It works ok on my side.

Will, try to press Tab before you start fueling.

Cheers,

[Hardy Heinlin]

My lower EICAS indicates TOTAL FUEL 38.0 and PRESELECT 359.4

1. When this happens, what's in your Aerowinx/Logs/errors.txt?

2. What does your EICAS TOTAL FUEL and PRESELECT indicate before you enter 100000?

3. What does your EICAS TOTAL FUEL and PRESELECT indicate before you click "Start"?

[Will]

I have to say, I'm embarrassed by this; it was user error on my part.

Avi was quite correct. I was typing in the requested fuel amount and then hitting "Start" without hitting Tab or Return while the quantity field had the focus. I've made sure to hit Tab or Return before starting the upload, and now everything is running fine.