I must be missing something. Issue takes place when I manually enter the ZFW (using a PFPX FP)into the payload page. If I don't touch it, the ZFW will remain stagnant as expected. As soon I manually enter in a weight (in this case 479.1) the displayed ZFW will jump to 486+ (not what I entered) and continue to climb by itself. 5 minutes later it was at 495 and climbing. If I attempt to re enter the desired weight again, it ignores it and whatever weight it had climbed to will remain and continue to climb. I also noticed if I select any of the preload amounts such as empty or max load, it will do the same.

This only took place in the -400 RR so far, I didn't have this issue while testing the -400F.

 

As expected, with a continuously climbing ZFW, my FMC preflight ZFW will change so my Vspeeds are never accurate for more than a few seconds.

 

What am I missing? This of course has never been an issue with the NGX or 777, but I understand the 747 is a different animal.

 

 

What am I missing? This of course has never been an issue with the NGX or 777, but I understand the 747 is a different animal.

 

I've heard this reported in various different add-ons, and also default aircraft.

 

What other add-ons are you using while this is happening?

This sounds like some other program is adding weight to your plane, I vaguely remember someone had this issue and it turned out to be some program they were using which added weight to simulate ice accretion.

Are you using FSCaptain by any chance? This addon simulates ice build up

I've got GSX installed but I haven't used it with the 747.

ASN, doubt it would have that effect. Maybe icing effect? It was snowing while on the ramp in DEN which is my test airport (flightbeam). But I've never seen that before. It was clear while testing the -400F come to think of it.

 

PFPX, but I only use it for initial planning then close it before loading FSX.

 

Other than that, just ORBX and various other sceneries.

This only took place in the -400 RR so far, I didn't have this issue while testing the -400F.

Does this occur using PMDG House livery or a specific airline livery.

I was in the British Airways-400 RR. The UPS-400F did not have the issue.

 

Shot in the dark, could the ASN icing effects option cause this?

 

 

Shot in the dark, could the ASN icing effects option cause this?

 

Try running without ASN, or turn the effects off temporarily and check to see if the issue persists.

Ok, heading to work. I'll give it a try tonight. Thanks all.

was in the British Airways-400 RR. The UPS-400F did not have the issue.

I am flying the NGX right now so I can't get at the 744 liveries to see what type of ice protection option has been selected. In the FMC PMDG>SetUp>Airplane>Equipment page 18 Line 2 there are two options. One for manual and one for automatic. Maybe the two planes are setup differently. If you are going to use KDEN for tests with ASN furnishing the weather I would make sure the auto option is selected.

 

I would try Kyle Rodgers suggestion first. Then when using ASN I would try the auto option. Let us know how it turns out.

So loaded the same aircraft at the same gate with both ASN running and off. No issues. Only difference is the weather, it's currently overcast with no snow/rain. I wonder if a simple computer restart solved the problem.

Update:

I had ASN add rain into the mix and my ZFW immediately began to raise again at the rate of 100 lbs every 10 seconds. Once I put ASN back into LIVE mode (no rain, just dry and cold), my ZFW actually slowly dropped back to my original ZFW at the same rate.

I think I figured it out. My test station (KDEN) was experiencing freezing rain yesterday. I didn't realize that's what was falling and assumed it was rain and snow. ASN did exactly what it was supposed to do and injected accurate weather in the form of freezing rain. The PMDG 747 did exactly what any airplane does and began to collect weight in the form of ice. Having had to clean a few aircraft after an ice storm, I can testify that it really screws things up. This is why flight ops are prohibited in most freezing rain conditions.

 

Well done PMDG. Wow, you guys thought of everything! My 747 was in prohibited flight conditions, and responded exactly the way it should be increasing its zero fuel weight.

 

The PIC (me) failed to identify this.

 

To test these results, I had ASN introduced freezing rain conditions, and normal rain or snow. The ZFW would rise with the freezing rain, and slowly drop back to the original ZFW once back to normal rain was introduced.

 

 

Well done PMDG. Wow, you guys thought of everything! My 747 was in prohibited flight conditions, and responded exactly the way it should be increasing its zero fuel weight.

 

As much as I'd like to take credit for this on behalf of the team, I don't think it's us doing it. It's either ASN or the sim itself.

Dude, you totally could have taken credit for that and I wouldn't have questioned it!