PMDG777 Fuel Quantity Decrease during cruise

[Robinnn 13]

Hey,

 

I have this problem too! Not on every flight but maybe on 1 out of 10 flights,

 

-I use PFPX for planning.

-I use ASN for the weather

 

Today I had this problem again.

 

The route was from Amsterdam (EHAM) to Cairo (HECA), 1800nm. ZFW: 228000kg, Fuel: 36500kg, B77W. Calculated by PFPX

I cheated a bit on this flight because during cruise I added fuel :rolleyes:

In total I added about 50.000kg fuel. If I didn't do that, I would have crashed above Austria.

 

So no, this is not a problem with my planning, system, PFPX, or ASN. But something else.

I do not know what causes this problem. As I just mentioned, it only happens in like 10% of my flights.

 

So to the person who started this topic, It may work on this flight, but I can assure you, it will happen again

[downscc 1,327]

 

 

in total I added about 50.000kg fuel.

 

Don't you think that it's odd that the amount you added was much greater than the total planned?

 

I just ran a quick comparison EHAMHECA with 77W and came up with about 89,774lbs (40,800 kg) for that trip so we've in the same ballpark with PFPX.  To have added another 50,000 kg (110,000 lbs) means something was very odd... I cannot even imagine how you could have more than doubled your fuel consumption.

 

Didn't you notice anything odd, like nearly doubled fuel rate during cruise?  Please try to take a few notes and add additional information to add meaning to your findings.

 

Yes, I am skeptical because if there was a bug like this in the 777 it would have generated hundreds of posts, rather than one, and we could reproduce it.  Without additional information there's no way to try to identify a problem with the 777.

[Mike777 163]

 

 

The route was from Amsterdam (EHAM) to Cairo (HECA), 1800nm. ZFW: 228000kg, Fuel: 36500kg, B77W. Calculated by PFPX

I cheated a bit on this flight because during cruise I added fuel :rolleyes:

In total I added about 50.000kg fuel. If I didn't do that, I would have crashed above Austria.

 

Hi, Robin,

 

By any chance, do you have flap controls working through FSUIPC?  I believe there is a problem with such a configuration in which the flaps appear to be fully retracted but the sim sees them as extended.  This would of course cause excess fuel consumption, but it should also cause speed and climb problems.

 

Just a thought.

 

Mike

[codechris 9]

He wrote 50.000 not 50,000 so I'm guessing that's where you're misunderstand came from downscc

 

I have had this issue before, although with the NGX and not the 777. I note that now I under the winds in the legs page, I don't. I also give myself more taxi fuel then the default. At what point do you turn on the APU Robinnn ? I've seen so many videos where this comes on very early, but it doesn't, unless you don't have a GPU at that airport (which doesn't exist in the sim world, but depends on what you are doing personally)

[downscc 1,327]

 

 

He wrote 50.000 not 50,000 so I'm guessing that's where you're misunderstand came from downscc

 

Hopefully, but it depends on his culture. Many places use periods instead of commas for separators and commas instead of periods for decimal.

 

Yes, if the total added was only 50 kg then I'd say there's a windage problem.  With PFPX, you have to make sure ASN is selected and active because it's not a default selection.

[Mike777 163]

 

 

He wrote 50.000 not 50,000 so I'm guessing that's where you're misunderstand came from downscc

 

I think that "50.000" is the European way of writing "50,000".  Anyway, perhaps Robin can clear this up.

 

Mike

[codechris 9]

No that's very true, English man currently living in France so I know the . , difference. However. European countries do not write . so the fact there was a . indicates he meant 50.000 and not 50,000 (which could mean 50.000 but we're back to the . anyway). Although, it could also be a typo

 

But yes, most European countries write with a , however England doesn't

[pcubine 143]

In total I added about 50.000kg fuel

Is this fifty kilograms or fifty thousand kilograms?

[skelsey 765]

I'm sure the OP will enlighten us, but realistically given that 50kg is an almost entirely insignificant amount of fuel on a 777 and it would be extremely unusual to write 50 to three decimal places, I'm betting he means fifty thousand kilos/50 tonnes.

[codechris 9]

You're probably right Skelsey. Even still, it still remains that both values are either far too small or far too big to be understandable :S

[skelsey 765]

Agreed: but 50kg, I suspect, would barely display on the totaliser, let alone make a difference between running out of fuel over Austria and making it to Cairo. So 50 tonnes is the only sensible answer.

 

It's also not clear how much was left on arrival: saying "I added 50 tonnes" does not in itself imply usage of all of that 50 tonnes.

 

Were 50 tonnes added, or was fuel added until the totaliser read 50 tonnes? Where in the flight deck are you reading your fuel figures from? How much was left on arrival? Does the 777 have a PROG page 2 with calculated vs totaliser fuel?

 

I believe the 77W burns c.8000kg/hr. 1600nm = ~4hrs of flight, therefore I would anticipate fuel requirements to be in the region of 32 tonnes plus reserves etc, so the initial calculated figure of 36.5 tonnes seems reasonable albeit on the low end of what I would expect.

 

How long did the flight take? Were you able to compare totaliser figures to the PFPX calculated fuel remaining figures at each waypoint? Did you notice what the SAT/TAT was at cruise level?

 

Something is not right, and the discrepancy is too large to be related to wind alone. However, it's a case of trying to figure out what the circumstances are that have lead to this abnormally high fuel burn. What did you do the same on this flight as on other flights where you experienced this problem?

[scandinavian13 5,192]

Right, but he also wrote that if he hadn't added fuel, he would've crashed over Austria. To me, this sounds like a gross calculation/loading error. Since I tested it prior to release through now, I've yet to run into a fuel situation, particularly like this.

 

Please post your numbers for comparison, otherwise, this one should be put to bed.

[Robinnn 13]

Wow, many respons after 1 day of working , glad to see people are trying to help.

 

-To start this post: I mean 50000kg (50 tonnes), not 50kg.

-I do not use FSUIPC to calibrate my controlls.

-I am also very skeptical about this because it is a very strange issue.

-I do not use the APU for a really long time. Maybe for about 15 minuts.

 

So I try to explain this a little bit better. If it happens again, I will record it. (Hopefully before saturday because then my holiday will start)

 

• I created my own panelstate: Engines off, APU on. (Every time after an update I delete the old panelstate and create a new one)
• At the gate I fill in my FMC, use PFPX for planning and ASN for the weather, including winds report in the FMC.
• When that is finnished I check my PROG page: At destination 8.6 (8600kg) left. Perfect!
• During taxi (which is looooooooong at Amsterdam) the fuel at destination reduces a little bit, which is normal.
• During climb it even decreases further, back to 5.0 at destination. At this point it got my attention. 
• During cruise it goes further down, even to the point that there isn't even fuel left at destination.
• So I check all the systems (and look from the outside :o) to be sure my gear is up, flaps are up, no fuel jettison or something else.
• Then I go to the page in the FMC where you can set the amount of fuel you want (FS ACTIONS - FUEL)

I don't know if you ever looked at this page during cruise but you see your fuel quantity slowly decreasing with about 3kg to 5kg per second.

But at my FMC it looks like this: 30000 - 29995 - 29991 - 29895 - 29890 - 29885 - 29880 - 29800.

You see where it goed wrong? No I did not make a typo. You can imagine that after a few hours of flying the damage is much bigger!

 

I also understand it is hard to imagine that this happens. As only 2 people reported about this. So the next time it happens I will record it.

 

Why I never reported this issue before? 

Too lazy maybe? Or because it only happens in 10% of my flights it wasn't really a big deal to me. And I thought I was the only one. But when I saw this topic I just had to respons because I wasn't alone anymore .

 

 

Regards,

Robin

Before I forget, here was the flightplan from AMS to CAI. The flighttime was the same as in the flightplan.

 

KLM FLIGHTPLAN - IFR  KLM553  PH-BVN  EHAM-HECA 

--------------------------------------------------------------------------------

ALL WEIGHTS IN KILOGRAMS (KG)                                    STD 09JUN/1505Z

--------------------------------------------------------------------------------

OFP 1 - PREPARED 09JUN/1454Z BY ROBIN CORNELISSEN  

 

KL553/KLM553        PH-BVN/B777-3ER GE                    ROUTE:        (MANUAL)

 

DEP: EHAM/AMS 36L   ELEV    -9 M    COST INDEX: 50        TTL G/C DIST:  1781 NM

ARR: HECA/CAI 05R   ELEV   136 M    INIT ALT:   FL107M    TTL F/P DIST:  1799 NM

                                    FUEL BIAS:  100.0%    TTL AIR DIST:  1779 NM

                                                          AVG WIND CMP: TL005 KT

ALT: HEPS/PSD 28    ELEV     8 M    108 NM

--------------------------------------------------------------------------------

CONFIG      DOW  PAX   CARGO   TOTAL   ULOAD LIM             ZFW     TOW     LDW

STANDARD 167829  404   21367   60359    9494 ZFW     MAX  237682  351534  251290

                                                     PLN  228188  264100  235857

                                                     ACT  ......  ......  ......

 

               FUEL    CORR    ENDUR

TRIP          28243  ........  03:51 

CONT 5%        1412  ........  00:13

ALTN HEPS      2985  ........  00:21

FINAL RESV     3272  ........  00:30

MIN T/O       35912  ........  04:55       .....................................

EXTRA             0  ........  00:00       CAPTAINS SIGNATURE  (....)

TAXI            340  ........  00:10       

RELEASE       36252  ........  05:05       I ACCEPT THIS OFP AND I AM FAMILIAR

                                           WITH THE PLANNED ROUTE AND AERODROMES

 

FUEL TANK CAP 147850 KG / MAX EXTRA FUEL 15433 KG LIM BY LDW

TRIP CORR FOR 3000 KG TOW INCR: +288 KG / 3000 KG TOW DECR: -288 KG

2000 FT LOWER:  +600 KG / EET 03:52  CLB: 250/310/84  DES: 84/310/250

 

EHAM/AMS   STD 15:05   ETD 15:05  ACT OFBL .....    EST T/O 15:15  ACT T/O .....

HECA/CAI   STA 19:35   ETA 19:16  ACT ONBL .....    EST LDG 19:06  ACT LDG .....

                                  TTL BLCK .....                   TTL FLT .....

 

ATC ROUTE: N0481F350 DCT EDUPO UZ738 MISGO UZ741 GMH UL603 DINKU UM867 NIPEL DCT

           NEMEK DCT AKIKA UN132 MAVAR/N0478F370 UN132 KUMBI DCT

 

 

ALTERNATE PLANNING

--------------------------------------------------------------------------------

ALTN/RWY DIST ALT/FL   COMP  TIME   FUEL   DIFF  ROUTE

HEPS/28   108 FL046M  TL015 00:21   2985      -  CVO V602 PSD

HEAX/04   114 FL049M  HD015 00:23   3281   +296  CVO A1 NOZ

HEBA/32   132 FL055M  HD019 00:25   3603   +618  CVO A1 NOZ

HEAR/34   153 FL064M  TL031 00:26   3681   +696  CVO V602 ISMLH V606 ARH

 

 

--------------------------------------------------------------------------------

AWY      WAYPOINT   MT    ALT  WND/VEL   TAS  DIST  FUEL REM / USED   LEG   ACC

         NAME             TMP     FREQ    GS   REM  POSITION          ETO / ATO

--------------------------------------------------------------------------------

         EHAM/36L         -9M                           35.9 /   0.3            

         SCHIPHOL                             1799  N5219.7 E00442.5 ...../.....

 

DCT      EDUPO     116   *CLB                   50      32.4 /   3.8   10  00:10

                                              1749  N5158.5 E00550.2 ...../.....

 

UZ738    NAPRO     130   *CLB                   11      32.1 /   4.2   01  00:11

-EDVV                                         1738  N5151.4 E00603.5 ...../.....

 

UZ738    DEPAD     131   *CLB                    8      31.8 /   4.4   01  00:12

                                              1730  N5146.1 E00613.2 ...../.....

 

UZ738    AMOSU     131   *CLB                   12      31.5 /   4.8   02  00:14

                                              1719  N5138.3 E00627.3 ...../.....

 

         *TOC      131 FL107M  227/021   481    14      31.1 /   5.2   01  00:15

                          -47            483  1704  N5128.7 E00644.7 ...../.....

 

UZ738    MISGO     131 FL107M  227/032   481     7      31.0 /   5.3   01  00:16

                          -48            482  1698  N5124.3 E00652.6 ...../.....

 

UZ741    GMH       109 FL107M  228/051   481    41      30.4 /   5.9   05  00:21

         GERMINGHAUSEN    -49   115.40   500  1657  N5110.2 E00753.5 ...../.....

 

UL603    TESGA     146 FL107M  230/057   481    52      29.6 /   6.7   07  00:28

-EDGG                     -52            470  1605  N5026.7 E00837.1 ...../.....

 

UL603    ESATI     135 FL107M  232/052   481    32      29.1 /   7.1   04  00:32

                          -53            483  1574  N5003.8 E00911.4 ...../.....

 

UL603    DETEV     135 FL107M  233/047   481    20      28.8 /   7.4   02  00:34

                          -53            483  1554  N4949.4 E00932.5 ...../.....

 

UL603    DINKU     135 FL107M  238/037   481    48      28.1 /   8.2   06  00:40

-EDUU                     -53            485  1506  N4914.2 E01023.0 ...../.....

 

UM867    XERUM     147 FL107M  243/033   480    30      27.6 /   8.6   04  00:44

                          -54            481  1476  N4848.7 E01046.1 ...../.....

 

UM867    BURAM     132 FL107M  245/031   481    10      27.5 /   8.8   01  00:45

                          -54            491  1466  N4841.7 E01056.9 ...../.....

 

UM867    WLD       132 FL107M  246/030   481    10      27.4 /   8.9   01  00:46

         WALDA            -54   112.80   491  1456  N4834.8 E01107.8 ...../.....

 

UM867    BAVAX     129 FL107M  250/025   481    29      26.9 /   9.3   04  00:50

                          -54            492  1427  N4815.8 E01140.5 ...../.....

 

UM867    MUN       129 FL107M  251/024   481     7      26.8 /   9.4   01  00:51

         MUNICH           -54   112.30   492  1419  N4810.8 E01149.0 ...../.....

 

UM867    VAVOR     135 FL107M  256/020   481    20      26.5 /   9.7   02  00:53

                          -54            490  1399  N4756.0 E01209.3 ...../.....

 

UM867    LOMRO     143 FL107M  262/017   480    15      26.3 /   9.9   02  00:55

                          -54            487  1385  N4744.0 E01221.5 ...../.....

 

UM867    NOKDA     135 FL107M  327/008   480    71      25.3 /  11.0   09  01:04

-LOVV                     -54            490  1314  N4651.3 E01330.5 ...../.....

 

UM867    REKTI     133 FL107M  357/009   480    23      24.9 /  11.3   02  01:06

                          -54            489  1291  N4635.1 E01353.8 ...../.....

 

UM867    NIPEL     133 FL107M  005/010   480     8      24.8 /  11.4   01  01:07

-LJLA                     -54            488  1283  N4629.4 E01402.0 ...../.....

 

DCT      NEMEK     133 FL107M  050/009   480    76      23.7 /  12.6   10  01:17

-LDZO                     -54            479  1207  N4534.5 E01517.9 ...../.....

 

DCT      AKIKA     130 FL107M  168/006   480   261      19.8 /  16.4   33  01:50

-LAAA                     -54            474   946  N4232.1 E01936.2 ...../.....

 

UN132    MAVAR     138 FL107M  124/001   480    66      18.8 /  17.4   08  01:58

-LWSS                     -54            476   880  N4140.2 E02031.8 ...../.....

 

UN132    BITLA     138 FL113M  345/002   478    61      17.8 /  18.4   08  02:06

-LGGG                     -55            479   819  N4052.5 E02121.5 ...../.....

 

UN132    ABLON     141 FL113M  265/018   478   196      15.0 /  21.2   24  02:30

                          -53            486   623  N3810.2 E02344.1 ...../.....

 

UN132    KEA       140 FL113M  261/027   478    45      14.4 /  21.9   06  02:36

                          -52   115.00   489   577  N3733.4 E02417.9 ...../.....

 

UN132    TUXEM     131 FL113M  259/035   478    54      13.6 /  22.6   06  02:42

                          -51            496   524  N3655.2 E02504.9 ...../.....

 

UN132    MADEX     132 FL113M  258/038   478    22      13.3 /  22.9   03  02:45

                          -51            496   502  N3639.2 E02523.9 ...../.....

 

UN132    KUPIS     132 FL113M  257/042   478    35      12.9 /  23.4   04  02:49

                          -50            499   467  N3614.3 E02553.9 ...../.....

 

UN132    NIBOX     132 FL113M  253/050   478    74      11.9 /  24.4   09  02:58

                          -49            499   393  N3520.6 E02656.4 ...../.....

 

UN132    LIAKI     133 FL113M  252/052   478    18      11.6 /  24.6   02  03:00

                          -48            499   375  N3507.7 E02711.1 ...../.....

 

UN132    LAPSO     133 FL113M  252/053   478     6      11.5 /  24.7   01  03:01

                          -48            499   369  N3503.1 E02716.3 ...../.....

 

UN132    KUMBI     133 FL113M  245/066   478   109      10.1 /  26.2   13  03:14

-HECC                     -46            495   260  N3342.8 E02845.0 ...../.....

 

         *TOD      144 FL113M  245/066   478   124       8.3 /  27.9   16  03:30

                          -46            475   136  N3157.1 E03003.0 ...../.....

 

DCT      HECA/05R  143   136M                  136       7.7 /  28.6   21  03:51

         CAIRO INTL                                 N3005.8 E03125.1 ...../.....

 

--------------------------------------------------------------------------------

 

 

 

WIND INFORMATION - OBS 09/JUN 06:00

--------------------------------------------------------------------------------

(CLIMB)             MISGO               ESATI               XERUM             

FL106M 224/008 -46  FL119M 222/013 -49  FL119M 229/035 -55  FL119M 238/027 -58

FL085M 229/019 -41  FL113M 226/022 -48  FL113M 231/044 -54  FL113M 241/030 -56

FL064M 234/009 -29  FL107M 227/033 -48  FL107M 232/053 -53  FL107M 244/033 -54

FL042M 038/001 -13  FL101M 228/042 -47  FL101M 232/057 -50  FL101M 243/034 -50

FL021M 053/011  -1  FL094M 229/051 -45  FL094M 231/055 -46  FL094M 239/033 -45

 

LOMRO               REKTI               AKIKA               BITLA             

FL119M 252/013 -59  FL119M 334/007 -59  FL119M 041/002 -56  FL125M 274/005 -54

FL113M 257/015 -57  FL113M 347/008 -57  FL113M 143/003 -55  FL119M 292/003 -55

FL107M 263/017 -54  FL107M 357/010 -54  FL107M 169/007 -54  FL113M 346/002 -55

FL101M 261/018 -50  FL101M 006/009 -50  FL101M 172/008 -51  FL107M 032/004 -54

FL094M 251/017 -45  FL094M 021/007 -45  FL094M 170/005 -46  FL101M 031/006 -51

 

ABLON               TUXEM               NIBOX               KUMBI             

FL125M 257/023 -52  FL125M 254/038 -52  FL125M 249/053 -51  FL125M 244/072 -51

FL119M 259/023 -52  FL119M 256/039 -51  FL119M 251/054 -49  FL119M 244/070 -48

FL113M 266/018 -52  FL113M 259/035 -51  FL113M 254/051 -48  FL113M 246/067 -46

FL107M 283/013 -52  FL107M 263/030 -50  FL107M 257/047 -47  FL107M 249/062 -45

FL101M 304/010 -50  FL101M 269/025 -48  FL101M 260/042 -45  FL101M 251/059 -43

 

(DESCENT)         

FL112M 241/078 -45  

FL090M 244/060 -36  

FL067M 245/044 -19  

FL045M 246/038  -3  

FL022M 264/018 +12

 

--------------------------------------------------------------------------------

END FLIGHTPLAN 00131  KLM553   PH-BVN   EHAM-HECA   09JUN2015

 

 

 

(FPL-KLM553-IS

-B77W/H-SDE1FGHIJ1RWXYZ/LB1

-EHAM1505

-N0481F350 DCT EDUPO UZ738 MISGO UZ741 GMH UL603 DINKU UM867 NIPEL DCT NEMEK

 DCT AKIKA UN132 MAVAR/N0478F370 UN132 KUMBI DCT

-HECA0351 HEPS

-PBN/A1B1C1D1L1O1S1 NAV/RNVD1E2A1 DOF/150609 REG/PHBVN

 EET/EDVV0011 EDUU0022 LOVV0056 LJLA0108 LDZO0117 LQSB0121 LYBA0143 LAAA0150

 LWSS0158 LGGG0206 HECC0314 RVR/75 OPR/KLM PER/D

-E/0455)

[codechris 9]

Just to make sure, the 777 is differently showing you everything in KG's isn't it, and not LB's? So you are entering, what you think is 36252KG but actually it's i
36252 LB's?

 

Although, that doesn't explain why the figure keeps dropping. Do you also load the flight plan in to ASN so it knows the route you're flying? Again, even if you didn't, that wouldn't cause this.

 

As someone stated, you had to add another 50,000 KG of fuel in flight, when in EHAM you only put in 36252KB, so I'm really struggling to see how in effect you would need to have around 90,000 KG for that flight.

 

What speed are you cruising at? And just to double check, how is the MCP setup? What is enabled and displaying?

[Robinnn 13]

Hello Chris,

 

• Yes, everything is in KG. PFPX, P3D, the airplane. Everything  (much more easy than LBS)
• Flight is loaded in ASN (Or else the winds in the FMC won't work.)
• Speed is normal, MCP is normal. Everything is normal.
• Cruising speed is ECON (CI from PFPX used)
• LNAV and VNAV on.

I am experienced in this aircraft so I do know what I'm doing. I do exactly the same thing every flight. But only on 10% of the flights, it goes wrong.

By the way.

 

Curently I'm cruising with KLM B77W from Singapore to Bali. And now everything works just fine. I haven't done anything different then yesterday.