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6 hours ago, scandinavian13 said:

There's some background logic to the guarded switches too. They're guarded for a reason, though I can't recall off the top of my head at the moment.

John or Alex will no doubt put more flesh on the bones, but the short reason is that crossfeeds 2 and 3 are managed by the Fuel System Management Cards (FMSC). They automatically open/close depending on the flap position and whether or not the CWT is feeding.

Hence 'on' (buttons pushed in) is not really 'on' as far as crossfeeds 2 and 3 are concerned -- rather it is, really, an 'automatic' position.

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I get the FUEL IMBALANCE >FUEL TANK/ENGINE warning, seemingly when I have taken off on a short leg with low % fuel on board.  The message appeared after about 1 hour flying.

In this flight I took off with about 30% fuel on a short 2.5 hour leg.  Yet, as can be seen in the screen shot, the fuel appears to be perfectly balanced.

https://www.dropbox.com/s/6mlsjzg3lchl4fv/FuelWarning.jpg?dl=0

I do not seem to get this problem when on long haul flights, departing with nearly full tanks.

Any suggestions?

 

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8 minutes ago, ozzieblr said:

Any suggestions?

Yes - manage the fuel correctly! 

FUEL TANK>ENG appears when the level in main 2 or 3 is below 1 or 4. This is the case in your screenshot.

Likewise, I forget the threshold for an IMBALANCE message but it is almost certainly referring to the 3.3 tonnes difference between the outer and inner wing tanks.

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7 minutes ago, ozzieblr said:

I get the FUEL IMBALANCE >FUEL TANK/ENGINE warning, seemingly when I have taken off on a short leg with low % fuel on board.  The message appeared after about 1 hour flying.

In this flight I took off with about 30% fuel on a short 2.5 hour leg.  Yet, as can be seen in the screen shot, the fuel appears to be perfectly balanced.

https://www.dropbox.com/s/6mlsjzg3lchl4fv/FuelWarning.jpg?dl=0

I do not seem to get this problem when on long haul flights, departing with nearly full tanks.

Any suggestions?

 

It's not balanced. There are 3,300 pounds more fuel in tanks 1 and 4 than there in tanks 2 and 3. A ""balanced" state and exists when the contents of all four wing tanks are identical. It's OK to have more fuel in the inboard tanks than the outboard, but not the other way around.

 

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Thanks for your info guys ... I used the standard PMDG fuel loading in the FS ACTIONS / FUEL menu, and when loaded, the fuel is balanced as you suggested.  I guess I need to learn the fuel management system better, as it is quite different from the craft I have been flying!

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If you have less than about 54 tonnes of fuel on board at the start of the flight, the fuel levels in each tank will be equal and you will therefore need to go tank to engine immediately. 

The usual method is to turn ALL fuel pumps and crossfeeds ON at the appropriate moment during the before start procedure and wait to see whether FUEL TANK> ENG is displayed (you may need to clear off the other EICAS messages first).

If not, carry on. If it is displayed, you will need to go tank to engine immediately, ie turn off the OVRD pumps in tanks 2 and 3 and close crossfeeds 1 and 4. This will ensure that fuel is burnt evenly from all four tanks during the flight. 

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Sorry for digging this thread out. :blink:

I noticed that the PMDG 747-400 QoTS II might be a little bit too strict with the FUEL TANK/ENG conditions.

On one of my last flights I configured the plane for the Tank-to-engine configuration as soon as I noticed that the amount in all tanks was equal (I didn't wait for the EICAS message). Although the conditions were met, I got the usual crossfeed and O/J pump messages.

I had to wait until the FUEL TANK/ENG message popped up before I was able to turn off the O/J pumps and crossfeed valves. According to the manuals, it should be possible to configure the fuel system with some tolerance (the amount of fuel in the tanks doesnt have to be exactly equal).

Another small items I observed:
During preflight (when on the ground and all entries have been made in the FMC) and  the INIT/REF key is pressed, the TAKEOFF REF page should be displayed. In the PMDG 747-400 QoTS II, the INIT menu is called instead. This is not correct, as far as I know. The PMDG 777 correctly displays the TAKEOFF REF page.

The EICAS message "> TCAS OFF" should not be displayed on the ground when the transponder is in standby or off in many cases, there was a long discussion on the Aerowinx Forum some time ago (there was a software update by Boeing and it only appears in the air after the takeoff inhibition ends). 

Best regards,
Dirk

 

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4 hours ago, schepma said:

might be a little bit too strict

According to...?

4 hours ago, schepma said:

According to the manuals, it should be possible to configure the fuel system with some tolerance

...yet no manual reference for me to look up.

According to...?

...and what is the tolerance you're alluding to?

4 hours ago, schepma said:

During preflight (when on the ground and all entries have been made in the FMC) and  the INIT/REF key is pressed, the TAKEOFF REF page should be displayed. In the PMDG 747-400 QoTS II, the INIT menu is called instead. This is not correct, as far as I know. The PMDG 777 correctly displays the TAKEOFF REF page.

According to...?

4 hours ago, schepma said:

The EICAS message "> TCAS OFF" should not be displayed on the ground when the transponder is in standby or off in many cases, there was a long discussion on the Aerowinx Forum some time ago (there was a software update by Boeing and it only appears in the air after the takeoff inhibition ends). 

...again...according to...?

Sounds a lot like you're making a lot of your own assumptions about how all of this works without knowing the specifics.

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Posted (edited)

Kyle,

I just pointed out a few items which confused me.

Regarding the TANK/ENG configuration:

The AOM states ‚equal to or less‘. So if I see on the FUEL synoptic page that I have 13.2 in Tank 1 and 13.2 in Tank 2 and configure the pumps accordingly, the EICAS messages indicating a wrong crossfeed configuration should not be displayed, correct? 

Regarding the FMC:

It took me a while to dig it out, please have a look at page 2.2-1 in the Bulfer‘s FMC GUIDE. The flow chart clearly states:

ON THE GROUND, PRE-FLT complete -> TAKEOFF REF page

Regarding the TCAS message:

As I said, I was referring to a discussion among specialists (who really know the plane in great detail) on the Aerowinx forum. I‘ll mail the relevant thread to you if you want.

It was not my intention to criticise your excellent product, I just want to help to polish it. ;-)

Best regards,

Dirk 

 

Edited by schepma

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32 minutes ago, schepma said:

The AOM states ‚equal to or less‘. So if I see on the FUEL synoptic page that I have 13.2 in Tank 1 and 13.2 in Tank 2 and configure the pumps accordingly, the EICAS messages indicating a wrong crossfeed configuration should not be displayed, correct? 

Bear in mind there is some rounding going on on the FUEL synoptic page. I don't know to what extent or how accurately the figures are transmitted to generate the EICAS message, but I would suspect this to be the issue. 

I am fairly certain standard practice is to wait for the >FUEL TANK/ENG EICAS to appear before reconfiguring the tanks in any event. To turn it the other way round: if the conditions for >FUEL TANK/ENG to display are not met (because it has not displayed) then by definition >X-FEED CONFIG must display if you turn off the overrides and close crossfeeds 1 & 4, no? It must be one or the other.

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When I complete the preflight entries in the CDU, select any other key and then select INIT/REF, I get the TAKEOFF REF page as indicated in the Bulfer book. Am I misunderstanding the poster's comment? 

 

Jim Erwin

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Jim,

You are right ... during preflight you get the TAKEOFF REF page until all entries have been made on this page.

However, once you made all the entries on this page and you press the INIT/REF key again, it should be displayed again (similar to the APPROACH REF page in flight). But instead, you‘ll see the main menu of the INIT pages.

In the PMDG 777, it is correctly simulated.

 

 

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On ‎4‎/‎5‎/‎2018 at 7:01 PM, schepma said:

I just want to help to polish it. ;-)

This assumes there's something to polish, which is why I pushed back.

I'm all for making our stuff better, but I cannot simply say "yes, you're right, let me go bring this back to the dev team to fix immediately" without first confirming you have ground to stand on.

This is an extreme example, but if someone showed up in the forum claiming that the flight deck should actually be purple, I'm going to ask for references and not simply run back to the team and say "hey, this random guy in the forum said the flight deck should be Barney Purple - please stop what you're doing to look into it!"

We have a Tech Team for each product we make, comprised of people who either fly or maintain the aircraft modeled. I know things can slip by them, but keep that in mind. This isn't just a bunch of coders who have never been in the plane (many of us have, one of us is typed at the very least). Regardless - again - I encourage you to let us know when you think something should be fixed, but do keep in mind that we need you to provide your references. To me, it is an expected formality (almost a responsibility, honestly) to show up and provide those up front.

On ‎4‎/‎5‎/‎2018 at 7:01 PM, schepma said:

The AOM states ‚equal to or less‘. So if I see on the FUEL synoptic page that I have 13.2 in Tank 1 and 13.2 in Tank 2 and configure the pumps accordingly, the EICAS messages indicating a wrong crossfeed configuration should not be displayed, correct? 

Your understanding is incorrect. See Simon's post.

On ‎4‎/‎5‎/‎2018 at 7:01 PM, schepma said:

It took me a while to dig it out, please have a look at page 2.2-1 in the Bulfer‘s FMC GUIDE. The flow chart clearly states:

ON THE GROUND, PRE-FLT complete -> TAKEOFF REF page

This is a pre-flight guide, and not a technical spec. Moreover, it is a 3rd party document that is not aircraft-specific that does not clearly state that this is an expected behavior. It's also behind a paywall (forewarning: do not post links to this material that has been posted in a public place for free access given that it is a paid document).

On ‎4‎/‎5‎/‎2018 at 7:01 PM, schepma said:

As I said, I was referring to a discussion among specialists (who really know the plane in great detail) on the Aerowinx forum. I‘ll mail the relevant thread to you if you want.

Forums are forums. There are a few things incorrect about some of the leading 747 sims out there. As much faith in our product as I have, I'm not going to point to it as a reference point for another sim. Point to the real plane.

The "who really know the plane in great detail" reminds me of the movie The Right Stuff, and I'll stand behind the line:
"No. No, it was not, Senator. Our Germans are better than their Germans..."

 

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On 09/04/2018 at 10:53 PM, scandinavian13 said:

This is an extreme example, but if someone showed up in the forum claiming that the flight deck should actually be purple, I'm going to ask for references and not simply run back to the team and say "hey, this random guy in the forum said the flight deck should be Barney Purple - please stop what you're doing to look into it!"

Kyle has a good point, but, if the team is not so busy... Someone on the Aerowinx forum said (about two years ago) that an FCOM had the following text:

Chapter 15
Alerts inhibited during take-off
EICAS advisory message TCAS OFF - inhibited on ground until 400ft RA.

Alerts inhibited during landing
EICAS advisory message TCAS OFF - inhibited from 400ft RA until go-around at 400ft RA.

A British Airways 744 pilot responded and said that he didn't get a TCAS OFF message in his company sim. Another 744 pilot (Atlas) commented that he had never seen the message on the ground. I also found a mention of it in an old Boeing Service Letter (circa 1998):

IDS software Update:

>TCAS OFF (Level C) Revised logic to inhibit the message if radio altitude is less than 400 feet.

It would be far easier for one of your real (current) pilots to check this than for me to look through hundreds of pages of Service notes. Also, if your pilot is from an independent airline, it would add a 5th reference.

Note that I have manuals which say the TCAS OFF message does appear on the ground, but they are well out of date. I also have a really old photo showing the TCAS OFF message on the ground during Standby Power only. This may either be because the photo was really old (pre-service bulletin) or because the relevant radio altimeters were not powered.

The comments on the Aerowinx forum were temporarily "muddied" because some of the manuals didn't specify if it was a takeoff inhibit or if the inhibit was in force at all times below 400feet. The big sim tests seemed to prove that it wasn't just a takeoff inhibit.

The EICAS message >TCAS OFF is not to be confused with the one on the ND (which does appear on the ground)..

Cheers

JHW

 

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Regarding the >FUEL TANK/ENG message. There is a 120 second timer applied to the message, so, in theory, the message should not appear until the inboard tanks are a few hundred kilos below the equal quantity point.

For PMDG: refer to System Schematic Manual  28-41-02 Page 101 sheet 3.

Perhaps the active pilots on the beta team can confirm this. i.e. the manuals agree with the real aircraft.

This delay should take care of fuel sloshing around in the tanks affecting the fuel quantities and regenerating the X FEED CONFIG message, although there is also a 120 second timer on the X FEED CONFIG message in certain circumstances (logic also in the SSMs)


Cheers

JHW

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