Considering the below OFP snippet
FLIGHT NBR XXX9500 DATE 30NOV22 SCHEDULE PLAN
ACFT REG N757XX EGNX STD 00.50 ETD 00.50
ACFT TYPE B75237 TXO 00.22
SELCAL ABFF STE 00.15 ETE 00.31
SPEED CLB 250/290/78 AVGWIND 308/001 TXI 00.08 STA 01.35
CRZ CI 40 TOC TMP M06 EGSS STA 01.35 ETA 01.43
DSC 78/290/250 ROUTE EGNXEGSS-MCT DIFF +00.16
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FMC DATA ENTRY
CO RTE ORIGIN RWY SID RAMP FUEL ZFW RES CI CRZ ALT
EGNXEGSS-MCT EGNX 09 DTY4P 19.4 175.2 11.2 40 FL150
DEST RWY STAR TOC WIND TEMP CRZ DESC WIND
EGSS 04 FINMA1L 311/001 -06 ECON 280: 348/039
150: 001/016
100: 307/002
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TANKERING NOT RECOMMENDED (LOSS 652 USD / 5000 LB) .
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TC CHECK - TERRAIN CHECK COMPLETED WITH NO RESTRICTIONS
TERRAIN CLEARANCE - METHOD I TERR HGT 587 FT ISA M01C
ENGINE/WING ANTI-ICE PENALTY APPLIED METW 231000 LB
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FUEL TIME DIST WCMP PLANNED OPERATIONAL
BURN OFF 4.5 00.31 0136 T002 PTOW 193.9 MTOW 203.2
ALTN/EGPK 7.8 01.03 0331 H022 PLDW 189.4 MFW MLDW 198.0
RESERVE 3.5 00.30 PZFW 175.2 115.6 MZFW 183.8
HOLD 0.0 00.00 PYLD 55.0
10 PCT 0.4 00.03
DISP ADD 0.0 00.00
MEL/CDL 0.0
REQUIRED FUEL 16.1 02.07
TAXI 0.8 00.22
TANKER 0.0
EXTRA 2.5 00.22
TOTAL FUEL 19.4 ALTERNATE DATA
EGPK FL380 CRZ CI 0 M022.
LANDING FUEL 14.2 01.58 N55 30.9 W004 36.7
FMS RESERVE 11.2 01.33 UTAVA1S UTAVA Q75 BUZAD T420 TNT
UN57 POL UN601 RIBEL RIBEL2P
There is no minimum enroute reserve required by the flag rules of 14 CFR. In this example with 3 minutes of contingency fuel as the percentage-based enroute reserve, that is all that is required above the line for this short intra-UK flight. In your list the 30 minutes is the final reserve (just like EASA) + 10 percent, the 3 minutes. But the fuels are considered separately as at least for the 121 operator, all that %-age based contingency fuel does NOT need to be protected as FMS Reserves, which is the sum of the 30 minute final reserve, and the fuel to the alternate. In this format, HOLD is the amount of fuel I’d add over and above the reg mins to account for probable holding at EGSS, and with WX of
TEMPO 3000/3010 SCT003 OVC015
PROB40 TEMPO 3000/3009 0300 FG BKN001
You bet if this was a real OFP, I’d be adding gas in the HOLD bucket, as that’s calculated at 1500’ at hold speed. In this format, the DISP ADD fuel is for any other condition which may delay the landing of the aircraft; me not trusting the enroute weather so I may add gas, ATC radar being NOTAMMed OTS so I might add gas. We have a company requirement that if going thru Turkish airspace between SE Asia and Western Europe, to add 15 minutes of DX ADD gas as that airspace is “interesting” right now. We also use EXTRA fuel as more fuel for the crew to have to react to problems on the line.
You asked for other reasons - there is one right there - MEL/CDL. Depending on which main tank fuel boost pump was on MEL on the 757, I’ll need 3000 lbs of MEL/CDL gas for that (which is not burnable), AND a minimum takeoff fuel of either 16000 lbs, or 24400 lbs (the added fuel of which to make the 16.0 or 24.4 is burnable), but it all goes above the line.
Some of our aircraft types have a MinFOD value - I can’t plan under any circumstances to plan to land with less than X on board, and our FPS will build up to that landing fuel to meet that X value stored in the aircraft database, and all that fuel is burnable.
Some of our aircraft types also have a Minimum Zero Fuel Weight. If the actual ZFW is below the Minimum (and on some aircraft types the empty weight is below the MinFW), then we add MinFlightWeight fuel (not burnable) to build the ZFW to the minimum.
Some aircraft require Ballast fuel, also above the line, to keep the aircraft in balance, especially when flying empty (or close to it), all of which is unburnable.
