Hi all. Not sure if this should be posted here, but since my question is in regard to two different acft I thought I might start a single thread here instead of two threads in different subforums.So I´m kind of obssessive compulsive (aren´t we all) when it comes to nailing a flight plan close to real world ops and I´m a little curious about certain fuel figures. Does anyone know what the average rw airline uses for minimum landing fuel in the 737NG family and 747-400s? I know PMDG´s 747 manual states that this figure is usually 11,000 kg for international flights and 8600 kgs for domestic ones. Is this close to the real deal?I recall reading somewhere that the minimum landing fuel for the 737NG fmaily shoud be somewhere around 1900kg but then I read elsewhere that it should be roughly half that figure - 900 kg (maybe someone mistook kgs for lbs). Anyway which is it? (I´m sure it has to be above 500 kg because otherwise you start getting problems with your hydraulics)And finally I would like to know if minimum landing fuel and reserve fuel mean the same thing? I suspect not. From my understanding reserve fuel is a law requirement which will be 10% of trip fuel or 45 minutes of holding at 1500 ft AFE at altn dest. Minimum landing fuel is what would be left in the tanks after you fly to destination, miss an approach, hold, fly to alternate, use your reserve fuel after getting there and finally land?Thanks for the clarifications

I can answer your question with numbers for the 737:The "Reserve" is the amount of fuel planned for at the destination. Usually it is minimum landing fuel, plus alternate fuel, and contingency. It can be reduced to minimum landing fuel if the dispatcher and PIC concur. Minimum landing fuel is the amount of fuel required by regulations at landing. It is 45 minutes for US domestic flights. That works out to about 1900kg in the 737. If that doesn't answer your question, I'll clarify it more.

In addition to the above if you want an added consideration on some flights there is the procedure known as tankering. If either the primary destination does not have the proper fuel for the next leg or the cost is much higher than let us say the departure airport, if the figures work out for maximum TO weight and landing weight the aircraft might carry enough reserve for the second leg or return trip. In the case of higher fuel expense then it becomes passenger count vs. fuel costs for maximum round trip revenue.

Thank you both to Joseph and Rom for the prompt replies. I just don´t understand how a flight could be dispatched with reserves being the same as minimum ldg fuel even with the pic´s accordance. Because for that to happen, then they would be assuming there´s no need for fuel to fly to the alternate and need for contigency fuel?I have seen flights dispatched with little or no contimgency fuel because they were expecting good wx, no holdings and to be cleared for the filed FL. However I have never seen a flight dispatched with no fuel for altn... and I thought it was actually reuiqred by law for flights to carry fuel for alternate destination. Can you please clarify Joseph? Once again thank you.

Yeah, filing for an alternate is only required if the if the weather conditions require it. See part 91 of the FARs. The JARs may differ slightly, but I doubt it is by much.

Sec. 91.167 — Fuel requirements for flight in IFR conditions. (a) No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to— (1) Complete the flight to the first airport of intended landing; (2) Except as provided in paragraph ( b ) of this section, fly from that airport to the alternate airport; and (3) Fly after that for 45 minutes at normal cruising speed or, for helicopters, fly after that for 30 minutes at normal cruising speed. ( b ) Paragraph (a)(2) of this section does not apply if: (1) Part 97 of this chapter prescribes a standard instrument approach procedure to, or a special instrument approach procedure has been issued by the Administrator to the operator for, the first airport of intended landing; and (2) Appropriate weather reports or weather forecasts, or a combination of them, indicate the following: (i) For aircraft other than helicopters. For at least 1 hour before and for 1 hour after the estimated time of arrival, the ceiling will be at least 2,000 feet above the airport elevation and the visibility will be at least 3 statute miles. (ii) For helicopters. At the estimated time of arrival and for 1 hour after the estimated time of arrival, the ceiling will be at least 1,000 feet above the airport elevation, or at least 400 feet above the lowest applicable approach minima, whichever is higher, and the visibility will be at least 2 statute miles.

Because carrying the extra fuel burns more fuel, airlines are motivated to have their aircraft land with the minimum possible. I have missed connections because a CRJ wasn't loaded with contingency fuel, and couldn't deviate around weather enroute. There was a news piece a few months ago that detailed how many "minimum fuel advisories" were being reported by airliners.

Hi, I read somewhere that the landing fuel minimum for the 747 is Short Haul 8tons, Long Haul 10 tons. For the 737 somewhere between 4 and 6 tons. richard welsh

Yeah, filing for an alternate is only required if the if the weather conditions require it. See part 91 of the FARs.

Well, airlines do not fly according to Part 91, they fly according to FAR 121 and they fall under more stringent rules. If the weather is predicted to be quite good they still have to carry reserves for so called 'technical alternate' - for example their destination airport can become unusable because of some accident, etc. For example I recall Virgin Atlantic flying 747 to San Francisco had normally as its technical alternate airport in Oakland, just across the bay. Also internal rules within the airline may require them to carry some extra fuel - apart of any regulatory demands. On top of that a captain on a given flight may ask for more fuel - he is always allowed to do that.

On top of that a captain on a given flight may ask for more fuel - he is always allowed to do that.

I've heard, from one of my professors back at Embry Riddle Aero. University (Who at one point worked for National Airlines), that one of the pilots there would always add additional fuel for the route because National would always have them running near minimums - apparently he added fuel so many times someone politely told him to stop and deal with the low fuel weight, or get canned [fired]. :( Of course that's all just gossip - nevertheless, interesting story.

Well, airlines do not fly according to Part 91, they fly according to FAR 121 and they fall under more stringent rules. If the weather is predicted to be quite good they still have to carry reserves for so called 'technical alternate'

Check part 121.639 and part 121.619. 121.639 states "( b ) Thereafter, to fly to and land at the most distant alternate airport (where required) for the airport to which dispatched;"Part 121.619 specifies that an alternate is only required for aircraft on IFR flightplans if for the 2 hour block surrounding arrival time the weather is forecast to be less than 3 SM visibility and/or have the cloud ceiling less than 2000 ft AGL.

Also internal rules within the airline may require them to carry some extra fuel - apart of any regulatory demands.

Very true. I know for a fact that SWA caries 35 minutes of additional fuel.

On top of that a captain on a given flight may ask for more fuel - he is always allowed to do that.

Also very true. Captains do this all the time to allow for contingencies enrotue or their own personal gut feeling about what the weather will do at the destination. The captain can also have the dispatcher specify an alternate in the flightplan, even if it isn't required.

Hi Folks,I'm not an expert like many of you but I had heard that some B744's flying long haul on such as the Kangaroo route (about 14.5 hrs SIN to LON) seem to allowed to have a reducing reserve amount that means they carry less fuel than if they had to plan 45 min res plus 10% plus alternate fuel. As I understand it, as they passed an enroute diversion point, they effectively refiled their flight plan to take into account their current position which altered their fuel requirements. This I believe caused some problems with a major Asian airline as they had a couple of B744's almost run out of fuel taxiing to the arrival gate. Something similar to the above allowed QANTAS to do L.A. to Melbourne in their B744's before they got their B744ER's as they actually flight planned to go to Sydney, then if the winds and fuel allowed they "diverted" to Melbourne. This was actually a schedulled flight where they operated like this for a long time.To me it seems like the airlines can do sort of what they like .... until it goes wrong!CheersGreg

As fas as I know, according to ICAO regulations, you need 5% contingency fuel which may be reduced to 3% if you file enroute alternates. 5% contingency fuel is 5% of your planned trip fuel. Also, if I recall it correctly, according to ICAO minimum landing fuel is 45min for (turbo)props and 30min for jets. So typical planning I use for Tu-154M (now at hand).2 hrs flight = 2* 5300kg/h* = 10600kg5% contingency = 0,05*10600kg = 530kgalternate 30min = 2650kgholding 30min = 2650kgminimum 30min = 2650kgThat makes estimated landing fuel about 8,5 metric tons.*during cruise fuel burn is approx 1600kg/h for each engine at about FL350 and mach 0.85. Then you need to add something for take-off and climb, but you don't use much during descent. So I'm still decreasing this number since I always have more fuel left as estimated. Also, I will try planning with 6000kg for the first hour, then 4800/hr. Need to test a bit with this, since I only do accurate fuel plans since a few months. Before I just guessed a bit.Dion Mollert

All very good answers.Part 121 specifies certain fuel loads, each for different operations. In the US, that falls to DOMESTIC and FLAG (International). Each has a different fuel requirement.Another thing that needs to be considered, is each operator's "Operation Specifications, or OpSpecs for short. This is ultimately what drives them.Typically (my Part121 knowledge is a little rusty since getting my Dispatchers Certificate back in 2007), you have this for minimum. (FAA PT 121.639)1. Enough fuel to get to destination.2. Enough fuel to continue to the furthest alternate (if more than 1 is required, you can have multiple filed).3. Enough to fly for 45 minutes with 1 engine inoperative in calm winds.Don't quote me on FLAG ops, but they are something like this (FAA Pt 121.645):1. Enough fuel to get to destination.2. Enough fuel for 10% of the time it took to get to destination (example: 5hrs, so 30 mins fuel).3. Enough fuel to continue to the furthest alternate (if more than 1 is required, you can have multiple filed).4. Enough to fly for 30 minutes at a 1500ft HAA altitude of the alternate (destination if not ALT required).And of course, the Captain/Dispatcher may add fuel. These columns can be:Taxi fuel: when I fueled UAL 737's, they always took 500lbs extra at KBIL, for the 4 minute taxi. Could be as much as 2000 lbs at KJFK or the like.Contingency fuel: basically extra fuel, that dispatcher decides should be added (example: thunderstorms are around, anticipate the need to maneuver, 1 hr added).Extra fuel: Any extra you want added.In the end, the Captain can always add more, but based on my experience...airlines don't like this. Mainly because, it costs more money to tanker extra fuel.Now, that said, while fueling on nice days you could see:CRJ's landing with as little as 3000 lbs737's landing with as little as 8000 lbsA300's landing with as little as 13000lbsWhen I rode jumpseat on an A330 recently, for a 5 1/2 flight, we landed with 11200lbs.Or, you could screw up like Lufthansa did once when I was fueling. On a flight from EDDF-KDEN, they landed with a fuel emergency at KBIL, and only had something stupid like 4000 lbs of fuel. The ATC guys told us they didn't have enough to do a go around.I know this is jumbled, but I hope it helps :(.