FMC Fuel Planning

[deltafan 1]

Hello. Just a question about the 747 FMC. On the Estimated fuel at arrival section of the VNAV cruise page, my estimated fuel keeps on getting lower and lower even though I have the AP engaged in VNAV and LNAV modes and keep cruising at the optimum altitudes and speeds. Why is this?

[Mats_J 2]

Ron,Could be any number of things. My first thought was that you are flying in a headwind you didn't tell the FMC about before take-off?...The FMC is just a computer. The more detailed information you put in before takeoff, the more accurate calculations you will get.When you takeoff the FMC has already made the flight and will use those figures for your turn.Hope it helps,

[deltafan 1]

I can't seem to figure out how to program headwinds into the FMC before the flight. Some help?

[Check_Airman 3]

Wind data is not fully modelled. Go to the RTE data page, enter the wind in the format ddd/sss (direction and speed) where the "W" prompt exists.

[mburkhard 23]

>I can't seem to figure out how to program headwinds into the>FMC before the flight. Some help?Ron,I think Mats' information is somewhat misleading for you. Now first things first: To enter wind data into your flightplan you have to select the "RTE DATA" part of your waypoints via the LEGS page.For that just switch to the LEGS page and look for the prompt on the R LSK 6 for RTE DATA. Note that you can not see that prompt while the ND is in PLAN mode.Then there you can put in the wind information you got from your Real Weather programme.If you have time put that in before departure. However on a long haul flight you might skip that for your climb phase, the reason being that you might have dozens if not close to a hundred waypoints to feed with wind. This is why also in the real world many pilots wait with that task until a later stage of the climb. The system won't have a problem with that. However your ETA's might not be accurate until you have completed those inputs.Hope this helps!Regards,Markus

[Captain2000 0]

(EDIT: Foiund the answer I was asking about. Thanks!)

[Guest Ray51]

you have two opinions for imputing winds. The most accurate is to got to the legs page and use route data to imput the winds at each waypoint, you can enter data for one or any number of waypoints you choose.A second and less accurate but faster way is to imput the average wind direction and speed in rsk2 of the PERF INIT page.This will assume the wind direction and speed imput for all waypoints that do not have an entry in the route data page.Ray

[Flightsummer 0]

I tried to put the winds forecast into the FMC as depicted: LEGS/RTE DATA/DDD/SSS/R5 and got the message "INVALID ENTRY"... Any help, please?

[Guest Andalouse]

:-newbie where can you find the enroute winds? And not with activesky or something else? I mean in a freeware program/webpage? Does that exist? I'm looking for that for quit some time.I had a flight from VHHH to OMAA and it took me an hour longer to get there because of a headwind. Also the fuel was luckely loaded to much....Thus in that area i'm new and i was wondering is there something out there for winds @ higher altitudes?greetingsNick

[Flightsummer 0]

Hi Nick,I use ActiveSky and there you can get the wind velocities and directions according to different flight levels and positions. But my question was how to get them into the FMS...

[Guest Andalouse]

But you first need them to enter them into the fmc :-)Nick

[mburkhard 23]

>where can you find the enroute winds? And not with>activesky or something else? I mean in a freeware>program/webpage? Does that exist? I'm looking for that for>quit some time.Nick,Well the wind charts are available for free at the following link:ftp://weather.noaa.gov/fax/Amaster_index.htmlHowever those charts are not really for typing in the winds into your FMC. For that you need a more precise information on what the winds are at what waypoint and with what speed on which flight level. I'm not aware of a freeware programme that delivers you that information along your route. You might want to go ActiveSky there, it's as real as it gets, you'll get the same weather briefing as real pilots do!Regards,Markus

[Guest Andalouse]

Matkus,thx for the response. Then i have to buy me activesky! (I like the program but it is antother, payware, addon. I want to save some money but i'm so addicted!!!!! :-) )I thought there was no other option. So i have to buy activesky, i don't want to be up there without any fuel!GreetingsNick

[jordanal 70]

Speaking of winds, in FSBuild2, is there a way to export the wind-info when I build a plan and export it to FS and PMDG? Am I missing an export setting in FSBuild2?I didn't know about the weather for each leg entry in the FMC but I'm already getting that data in FSBuild2 from ASv6 while generating a flight-plan. In other words, for each leg in FSBuild2 I see the weather in the last two columns but how do I succesfully export it within the plan so the PMDG FMC will automaticlaly import it for each leg. I certainly don't want to type in all that info by hand in the FMC for long-hauls if I already have the tools to automate the job.v/r,Al

[mburkhard 23]

>FSBuild2 I see the weather in the last two columns but how do>I succesfully export it within the plan so the PMDG FMC will>automaticlaly import it for each leg. I certainly don't want>to type in all that info by hand in the FMC for long-haulsAl,what you are looking for is not possible. FSBuild exports you the route so you can load it via the Company Route function within the FMC (that first step is as real as it gets, most of the time).Now automating wind information input is another story. The situation today is that still most of the airlines use the good old print-out from Dispatch/Meteo which then the pilots have to put in whenever they find time. There are newer systems available to automate that very task by using ACARS. However ACARS can be very expensive and the aircraft needs to be fitted with that function as well. So as I said many airlines still don't have that function in use, which makes putting in the wind by hand as real as it gets...The airline I'm most familiar with (Swiss International Air Lines) still requires manual wind input on their fleet including long haul A332 and A343. And of course it had to be done manually on the MD-11 back then...Regards,Markus