Fsbuild-2 Flight Planner

Hi, I have a question about the FSBuild calculation for Holding and Reserve fuel.

If I take for example the default FSBuild 737-800 (CFM) and insert :30 in the Holding and Reserve fuel I obtain different ouput values for a route.

Example: LIPZ-LIRF with 737-800
Reserve: 1681 kg - 30 minutes
Holding: 1134 kg - 30 minutes

about 547 kg of difference.

They are considered differently from FSBuild, even if they have the same time value?

I suppose FSBuild has a different mode of calculating the Holding and Reserve fuel, in spite of the value of 30 minutes is the same for Holding and Reserve fuel. Is it correct?

Thanks a lot

Fsbuild Flight Plan
FLT REL IFR AAL1944 KDTW-22L/KATL-26R MACH 80 A/C B767-300 Level-D
FUEL TIME CORR TOGWT LDGWT AVG W/C
TAXI 003420 0019 . . . . 314604 296005 M028
DEST KATL 018599 0130 . . . . ELEV. 1026 FT
** RESV 007450 0045 . . . .
ALTN 002607 0015 . . . . ALTN Kcsg DIST 72
*** HOLD 002483 0015 . . . .
EXTRA 001000 0006 . . . . ZFW 282465 PAYLOAD 085465
TTL AT TO 032139 0251 . . . . DIST 0588
REQD 035559 0310 . . . . ETD

** 45 minute reserve for the 763
In the USA, for example:
The FAA requires.
Fuel to destination + Fuel to Alternate + fuel for 45 minutes at normal cruise.


***
If you are expecting enroute hold(s) because of bad Wx:
Preflight/dispatch brief: then you add it in the HOLD box.


****
Last line of the FSbuild NavLog:
13500 lbs reserve ... this is the FMC entry for reserve fuel = cockpit warning, low fuel.

N3343.8/W8450.8 274 DSC 284015 ATL
WOTBA 005 FLCON3 274 280 266 00/01 01/25 KFTY/ 0170/... 0151/...

N3338.2/W8425.6 107 DSC 284015 ATL
KATL 021 FLCON3 107 250 264 00/04 01/30 KFTY/ 0185/... ****0135/...

For Europe check the rules and adjust the above information.

_________________
Vaughan

Thanks von (mine was a different question) and Ernie, but the values are different for the same time.

Try to make LIPZ-LIRF (but route is not important) with default 737-800 (but for the others aircraft it's the same! I tried even ATR-42) inserting:

HOLD :30
RESERVE :30

you will get different data. For 737-800 I've got:

FLT REL IFR RYR7471 LIPZ-22L/LIRF-34L MACH 78 A/C B737-800 W/ CFM56-7B26
FUEL TIME CORR TOGWT LDGWT AVG W/C
TAXI 000113 0010 . . . . 063949 061738 M016
DEST LIRF 002211 0042 . . . . ELEV. 15 FT
RESV 001681 0030 . . . .
ALTN 000882 0015 . . . . ALTN LIRA DIST 15
HOLD 001184 0030 . . . .
EXTRA 000000 0000 . . . . ZFW 057991 PAYLOAD 015000
TTL AT TO 005958 0148 . . . . DIST 0252
REQD 006072 0158 . . . . ETD

My weights are in kgs because I've changed the data in fsb_aircraft.cfg file, but in lbs the result is the same: different weights for the same time.

It's for that reason I ask about the method of calculation by FSBuild.

Edit: is the calculation probably obtained considering the altitude (for reserve fuel the standard is 30 minute at 1500 feet AGL) and meteo data from ActiveSky?

Ok Ernie this is the complete Navlog.

Before I want to tell you I have change from LBS to KGS and consequently transformed all the values in kilograms.

Here is the default 737-800 modified by me in KGS in fsb_aircraft.cfg (the strange behaviour even remain using LBS, with the same result, here you can see KGS):

[B737-800 w/ CFM56-7B26] -- (M.Brodbeck) ---
WeightUnit=KGS
OperEmptyWeight=42991
PayloadWeight=
ReserveFuel=:30
AlternateFuel=
HoldFuel=39.46/min
ExtraFuel=%5
TaxiFuel=11.34/min
ApproachFuel=
MaxTakeoffWeight=79182
MaxZeroFuelWeight=63773
MaxLandingWeight=66361
MaxFuelWeight=20820
ImageFile=ryanair.jpg
CallSign=RYR7471
PerformanceData=b738.prf
ToldData=
DefaultTOFlaps=5

Then build the flightplan using routefinder: LIPZ-LIRF airac 0904, LIPZ SID CHI5V and STAR for LIRF BOL3C, alternate LIRA, holding 30 minutes and reserve fuel 30 minutes. This is the Navlog:

FSBUILD FLIGHT PLAN
BLOCK TIMES FLIGHT TIMES FUEL

IN . . . . . ON . . . . TAKEOFF . . . .
OUT . . . . . OFF . . . . LANDING . . . .
TOTAL . . . . . TOTAL . . . . BURNOFF . . . .

FLT REL IFR RYR7471 LIPZ-04R/LIRF-16R MACH 78 A/C B737-800 W/ CFM56-7B26
FUEL TIME CORR TOGWT LDGWT AVG W/C
TAXI 000113 0010 . . . . 048780 046606 M020
DEST LIRF 002174 0043 . . . . ELEV. 15 FT
RESV 001594 0030 . . . .
ALTN 000837 0015 . . . . ALTN LIRA DIST 15
HOLD 001184 0030 . . . .
EXTRA 000000 0000 . . . . ZFW 042991 PAYLOAD 000000
TTL AT TO 005789 0150 . . . . DIST 0245
REQD 005903 0200 . . . . ETD

CLB BIAS 0.0% CRZ BIAS 0.0% DSC BIAS 0.0%
DEP BIAS 0 MIN 0 DIST 0 FUEL, ARR BIAS 0 MIN 0 FUEL

LIPZ CHI5V UY106 GITOD BOL3C LIRF/0043

M/H FL WIND ATC
TO NM AWY M/C TAS G/S ZT ACTME STA/CODE ACBO ABO REM AREM

N4532.5/E1224.0 045 CLB 158007 LIMM
D041B 003 CHI6Z 044 343 345 00/00 00/00 LIPZ/ 0000/... 0057/...

N4527.3/E1231.1 133 CLB 158007 LIMM
D119G 007 CHI6Z 133 343 337 00/01 00/01 LIPZ/ 0001/... 0056/...

N4524.0/E1239.2 116 CLB 121006 LIMM
D119N 006 CHI6Z 116 343 338 00/01 00/02 LIPV/ 0002/... 0055/...

N4504.2/E1216.8 215 CLB 155012 LIMM
CHI 114.10 026 CHI6Z 217 343 338 00/04 00/07 LIPV/ 0006/... 0050/...

N4434.2/E1215.5 179 CLB 183024 LIMM
TOC 030 UY106 179 343 320 00/05 00/13 LIPV/ 0012/... 0045/...

N4424.3/E1214.8 180 250 187025 LIMM
DITUM 020 UY106 180 471 447 00/02 00/15 LIVM/ 0013/... 0044/...

N4349.0/E1213.0 178 250 187025 LIMM
PIDEP 035 UY106 177 471 447 00/04 00/20 LIVM/ 0016/... 0041/...

N4329.8/E1212.1 180 250 190028 LIRR
RUNIM 020 UY106 180 471 444 00/02 00/23 LIPR/ 0017/... 0040/...

N4319.8/E1211.6 182 250 183027 LIRR
TAKUP 010 UY106 182 471 445 00/01 00/24 LIQB/ 0018/... 0039/...

N4303.9/E1210.8 180 250 183027 LIRR
NIKMA 016 UY106 180 471 445 00/02 00/26 LIQB/ 0019/... 0038/...

N4256.6/E1215.1 158 250 187029 LIRR
TOD 008 UY106 156 471 446 00/01 00/27 LIRZ/ 0019/... 0037/...

N4248.0/E1218.6 159 DSC 187029 LIRR
GITOD 008 UY106 156 318 306 00/01 00/29 LIRZ/ 0020/... 0037/...

N4237.1/E1202.9 221 DSC 187029 LIRR
BOL 114.40 016 DCT 224 306 284 00/03 00/32 LIRZ/ 0020/... 0037/...

N4213.4/E1208.3 169 DSC 193028 LIRR
D169X 024 BOL3C 167 306 281 00/05 00/37 LIRV/ 0021/... 0036/...

N4204.5/E1210.4 168 DSC 171028 LIRR
BOL33 009 BOL3C 168 306 279 00/01 00/39 LIRB/ 0021/... 0036/...

N4201.4/E1211.1 164 DSC 173029 LIRR
MIKSO 003 BOL3C 164 306 278 00/00 00/40 LIRB/ 0021/... 0036/...

N4148.0/E1214.3 167 DSC 164019 LIRR
LIRF 013 BOL3C 168 306 288 00/02 00/43 LIRB/ 0021/... 0036/...


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

(FPL-RYR7471=IS
-B738
-ZZZZ-LIPZ0000
-N0445250 LIPZ CHI5V UY106 GITOD BOL3C LIRF
-LIRF0043 LIRA
-)


I hope you can solve this strange behaviour , it's a mine curoisity,

Riccardo

Thanks guy! I've solved, I leave blank "holdfuel=" (I thought it was mandatory) and now this is the correct output:

FSBUILD FLIGHT PLAN
BLOCK TIMES FLIGHT TIMES FUEL

IN . . . . . ON . . . . TAKEOFF . . . .
OUT . . . . . OFF . . . . LANDING . . . .
TOTAL . . . . . TOTAL . . . . BURNOFF . . . .

FLT REL IFR RYR7471 LIPZ-04R/LIRF-16R MACH 78 A/C B737-800 W/ CFM56-7B26
FUEL TIME CORR TOGWT LDGWT AVG W/C
TAXI 000113 0010 . . . . 049304 047124 M020
DEST LIRF 002180 0043 . . . . ELEV. 15 FT
RESV 001594 0030 . . . .
ALTN 000837 0015 . . . . ALTN LIRA DIST 15
HOLD 001594 0030 . . . .
EXTRA 000107 0002 . . . . ZFW 042991 PAYLOAD 00000
TTL AT TO 006313 0200 . . . . DIST 0245
REQD 006426 0210 . . . . ETD


Great FSBuild!

A little curiosity........

for deafult 737-800 in the file fsb_aircraft.cfg when I purchased FSBuild there was:

HoldFuel=86/min (libbs)

so I convert to kgs

HoldFuel=39.46/min (libbs)

But either for libbs or kgs there was the same difference between Holding fuel and Reserve fuel, because it's a multiplication factor that involve a number, for example:

100 x 86/min = value X in libss

and

100 x 39.46/min = value X in kgs

but there will be anyway ever difference with Reserve Fuel, like told before in the first post.

That value differ anyway from reserve fuel if you don't leave it blank the parameter "HoldFuel=", either if you use libbs or kgs.

So, my curiosity, if it's correct to leave it blank, why did you assing a specific value (86/min) to it? Is it better to leave blank also the other aircrafts "HoldFuel=" field?


Thanks a lot,
Riccardo