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Guest Flightle

Fuel Consumption and ILS/LOC tune problems

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Guest Flightle

To any concerned,Most likely it is due to my own fault that I am having issues in these two categories. First, planned vs. actual fuel consumption.Looking at the fuel planner we plan for:Alternate .Holding .Min Landing . FUELS in total lbs. Enroute .Taxi . =====Total Frequently, after careful planning and EXCEEDING the fuel requirements for the trip, the FMC system will report inadequate fuel while on the ground, then during the trip it will show enough fuel to land but I always consume some of my reserve allocation despite the careful planning. I include cruise winds, ISA dev, time for vectoring and decent winds into my fuel thought process. My main questions then would be: Is it an error of the FMS to tell me inadequate fuel while on the ground? What EXACTLY should constitute "Reserves" for the enterance into the FMC? ====================================================================Second, frequently during flights I have problems with the aircraft not recieving Localizers. Sometimes I get no localizer. This used to be more of a problem before my 800/900 update. I operate on the most current AIRAC always. I have extensive Mode Control Panel experience so its unlikely that I have the modes set up incorrectly. This IS a possiblity though. When I cant recieve the localizer (or entire ILS for that matter) I am forced to revert to internal FMC VNAV/LNAV of the approach without the radio nav as the primary. While reflecting on my problems I realize that I need to read the manual again to make sure I didnt miss anything. I don't believe that I have and your input is greatly appreciated!Thank You,Forest J. Lightle IV

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Forest,It sounds as if your flight planning is adequate, however, I suspect you are not entering a figure into the Reserves area of the FMC. Without an adequate reserve fuel figure entered, you will get the "insufficient Fuel" message. When planning your fuel, your resrve fiure as I understand it is normally enough fuel to make your alternate or 45 minutes of fuel. God knows this in not my area of expertise so someone should be able to provide more accurate figures.You don't say how you are attempting to tune the Loc/Ils, but it is normally tuned from the Radio panel Nav 1 (and Nav 2 if you plan an autoland). Simply dial up the frequency and set the Course selector on the MCP for Inbound Course. Regards Paul Gollnick :-cool Technical Operations/Customer Operational SupportPrecision Manuals Development Groupwww.precisionmanuals.comhttp://www.precisionmanuals.com/images/forum/devteam.jpg


Paul Gollnick

Manager Customer/Technical Support

Precision Manuals Development Group

www.precisionmanuals.com

PMDG_NGX_Dev_Team.jpg

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Guest Flightle

I alway have a reserve amount entered into the FMC. It's usually no less that 4,500 lbs. Thats nearly an hour at cruise. This is broken down to about 2500 alternate, 1000 min landing, 500 taxi, 1000 holding. Even with these numbers in there, I still tend to burn more than the fuel planner says and I still get some insufficient fuel warnings while on the ground. I have a feeling that it has to do with a spike in altitude winds that the FMC is sensing. As soon as it sees unfavorable conditions it will warn me. Any other ideas guys?Thanks!

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Forest,You may have set the RESERVE FUEL entry too high on PERF INT page during preflight. Lets say you plan a flight with 11,000 lbs of fuel on board at takeoff and the fuel burn to the destination is 5000 lbs. That mean you are planning to land with 6000 lbs. On the PERF INT page, if you enter a RESERVE FUEL of 7000 lbs, then you will get a FMC message USING RESERVE FUEL on the ground because the airplane will use 1000 lbs of reserve fuel to get to the distenation.Usually plan to land at the destination with at least 5000 lbs. If WX is not good, use 5000 lbs plus the fuel burn off to the alternate. For example, if fuel burn off to the alternate is 2300 lbs then the RESERVE FUEL entry on the PERF INT page should be 7300 lbs.Make sense?Floyd


John Floyd

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