Sign in to follow this  
JSACKS

744: FMC LEGS, RTE DATA wind question - Big flight

Recommended Posts

I have programmed a 6000nm flight with 17 pages of wp in the LEGS pages. I expect an average headwind of 50 knots during the flight. Do I have to enter an estimated hdg/headwind spd in every single field of the RTE DATA pages for this huge flight or can I insert an average for all 17 pages, or what options do I have?Thanks!Jonathan

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

As far as I've found, there is no average wind data entry field in the FMC. That might seem reasonable too. One important job the FMC does is to provide very precise fuel burn projections, waypoint by waypoint . . . and they are all important. An

Share this post


Link to post
Share on other sites

Just an addon to what Sam says. You have the option to enter your average wind in the first waypoint since it

Share this post


Link to post
Share on other sites

I know this will be a long post and many of you will probably disagree but....I used the excellent PS13 744 for many happy years & after changing over the the 'Queen' I have found this method almost foolproof if not '100% real-world' & very accurate; I often fly long routes (WSSS-EGLL, YSSY-KLAX, VHHH-EHAM etc).I check the current wind & wx & temp forcasts via the internet, then manualy upload this info into the FS wx menu prior to selecting my aircraft. Yes - this is a time consuming method but it means I am using a 'clean' system with less add on programmes; I have noticed that several wx add-ons and/or connection to the internet during FS9 flights can make a serious dent on my frame rates even with a fairly high-spec system like mine. My 'FS9 computer' is not currently hooked up to the internet for this reason.If you save a flight at your favourite airfield with the default FS9 Cessna loaded with the following wx data entries you will find that changing these settings takes less than 5 mins with practice.I currently enter wind data in the foll areas:1. Worldwide:Wind dir/speed at the following alts:FLs 50, 10, 150, 200, 250, 300, 320, 340, 360, 380, 400, 420,- if sig wind data exists between these FLs I will also add it to.I usually set 30 NM vis & 1 or 2 layers of cloud.Average temps at Sea Level, FLs 100, 200, 300 & 350 (ISA or actual)An average pressure setting for my route of flight.2. In an area up to 100 NM around dep/arr & altn airports:Surface Wind (incl turb/windshear if nec) up to 3000 AGL.Temp & dewpoint & QNH/QFE press settings.Clouds & visibility settings as required (based on current/forecast TAF/METAR data).I then commence a paper fuel burn calculation - using Planned Landing Weight arriving at the final fuel figure (burn + altn + contingency + res + taxi etc)I then select my dep airport & stand prior to selecting & setting up the 'Queen' - I use a CH Pedal/Yoke, Aerosoft Australia MCP & dual monitors.I upload the wind data correct for my initial flight level at the first 5-10 waypoints at that level in my flightplan route. I also place a wind data entry at the first waypoint at each step climb point & I find this gives me a very accurate fuel/ETA prediction on the Prog Page 1/3. I can always adjust the final fuel figure not forgetting to adjust wind entries as the actual step climb point will move up or down the planned route if the final fuel figure (a/c weight) goes up or down.I use the excellent TOPCAT tool for my take-off calculations.I then ensure the time (GMT/UTC & date) are correct.Once at my initial flight level I interpolate the actual wind data at the top of Prog Page 2/2 & manually enter this data in the legs page next to each waypoint at that flight level, not forgetting to monitor the actual step climb point, which may change depending on the actual fuel burn taking into account actual winds encountered.After each step climb I carry out the same process.At about 2/3 of the way through the flight ('tank to engine' is a good time) I also enter wind data in the forecast winds part of the Des Page at the following flight levels:Final Flight level.2. FLs 300 or 250, 200 & 100.I select my STAR/SID/ARR at an appropriate point at this stage -sometimes I will select the STAR at the intiial planning stage if this is appropriate - this will affect the fuel calculations, so more often than not I will select the STAR after loading my saved route - after all that is what a STAR is - a Standard Arrival Routing.Using this method I find I am almost always able to hit my fuel burn predictions/waypoint ETA predictions.I would be very interested in feedback on this issue.Hope this helpsBlue skies & happy landings!!Steve B

Share this post


Link to post
Share on other sites

I understand your general drift (!!) but I am PRECISELY interested in the fuel remaining on landing because otherwise I get INSUFFICIENT FUEL triggered during the flight. Let's just say for the sake of this exercise that I expect a wind of 270/70 the whole way over from east to west. I've got a headwind or a x-wind the whole way over.When I fly, I track the PMDG 744 with FSNavigator. FSNAvigator seems to have more accurate times than the FMC because it looks at the groundspeed of the flight. This is what I need the FMC to do in the 744 as well because there is a large discrepancy on a long flight between the calculated time to destination in the FMC as compared with "reality" (FSNavigator). If my flight takes 1 hour longer than anticipated because of wind, my reserves need to be 24,000 lbs larger or I need to load 24,000 lbs of extra fuel somewhere.This is why I asked about whether it is necessary enter the wind (albeit an "average" expected wind) for every waypoint. I am trying to simplify this part of the simulation. Surely it will give me a more accurate read on total flight time and expected fuel consumption, no? And all I am looking for is a short-cut method to do this, if such a short-cut exists in the FMC, but I don't know that.Jonathan P.S. I no longer have my FS9 PC online, so I never use real wx. It created too many problems for me in the past and I prefer my PC to be clean and free of any other apps, utilities, and a web connection. I use only the FS9 wx. engine and tweak that for personal preference.

Share this post


Link to post
Share on other sites

Dear Jonathan,I understand what you are trying to do but I fear there is no shorcut solution :-(As you are probably aware the 'INSUFICIENT FUEL' msge is linked to the RES entry you place into the Perf Page prior to departure.As others have said, the FMC seems to be the best fuel calculation tool out there.Unfortunately the PMDG 744 FMC does not accurately replicate the Waypoint Wind data entry facility as found in the real deal machine (& PS13!!). If it did you would be able to enter wind & temp data at mutiple levels which would be propagated backwards & forwards in the legs page. This would also be of assistance if you were in a wind/altitude trade off scenario.Hopefully one day this crucial element will be faithfully replicated & we will be able to upload wind & temp info like they do in the real world.I may be wrong but I think that my method does go some way to replicating this... but I may be wrong.My previous comments we just an illustration of my method, sorry if that was not the answer you were looking for.RegardsSteve B

Share this post


Link to post
Share on other sites

Here is my rule for inserting winds that i get from ASv6/FSBuild.1. Insert the W/V at the first waypoint after Top of Climb.2. Insert the W/V whenever there is a change of 30 Degrees or 10 Knots.3. Insert the Descend W/V for FL's 340/240/120/060.If you do it this way, your FMC preditions will be fairly accurate.Happy landingsPalle

Share this post


Link to post
Share on other sites

Jonathan, dont you remember that old Captn Tarmack learned us in de long gone past? always use 24.000 pounds per hour regarding the planners? its always in the ballpark, sometimes a bit more, sometimes a bit less, but he was very confident in this average figure, disregarding winds, delays etc.. and not to forget BMF's.Works all the time!Johanps: pls read again: http://www.avsim.com/pages/contrails/contrails_ott3.shtmlA LITTLE LESS CONVERSATION, AND A LITTLE MORE ACTION PLEASE

Share this post


Link to post
Share on other sites

Hey, Johan:I sure do remember the Venerable Great One O' The Skies--who among us doesn't ?! In this case, I was looking for a way to make the FMC reflect the estimated flight time and give guidance for fuel. I was just looking for "The Magic" inside the FMC to give me a scientific answer--easily. I do generally work on the basis of 24K/hr. and it's saved my bacon a lot over the years.How are ya?JS

Share this post


Link to post
Share on other sites

All fine here, all fine.I think if you use average winds, you get an average fuel burn. So it wont be exact, if you want exact figures, then you need to enter them all, or skip one or two.Its the one or the other.JohanA LITTLE LESS CONVERSATION, AND A LITTLE MORE ACTION PLEASE

Share this post


Link to post
Share on other sites

Steven BThanks for the detailed replies. We can all learn something from someone who has such an eye for detail and such a good understanding of systems - I will certainly print out all the replies - thanks!Gerry

Share this post


Link to post
Share on other sites

>Now adjust your fuel load so that the FMC>is calculating that much fuel remaining at your destination.>There are simply no flight planners that will do this as>accurately as the PMDG FMC. Hi Sam, all,I found this relatively old subject in the search function.I completely disagree with the accuracy of the FMC - it is simply wrong all the way and will only get better if you get nearer to destination.After about 1000 hours in the log with both 737 and 747 I found out that on ALL flights the FMC of the 747 showed me - especially on 3000+ nm flights - wrong fuel figures ( fuel remaining at waypoint )for at least the first half of the flight.One example out of more than 100 flights :EDDT-KSFO 5100nm ETE 10:47 based on winds from ASv6 and own flightplanning tool ( of course based on PMDG manual ) W/C MINUS 17weights in lbsZFW 533,5 - TTl Fuel 311,2 + 2,0 taxi - calc. burn 267,7 - TOGW 844,7Winds from ASv6 entered into FMC and online with ASv6.After T/O ( after entering the winds !)at 0911 z :DING DONG - INSUFFICIENT FUELFuel at DEST : 29,4 with an ETA of 20:08 ( plus 10 mins based on calculation ), this will continue for a while and will increase by 100 lbs every 100 nm.To make a long story short : Flight ended exactly on predicted ETA at 2008 with fuel remaining 51,2 !!! The fuel remaining figures were wrong until about YFB, then they came slowly back to correct figures.Also the fuel-flow figures in the FMC ( calculated by difference of fuel remaining between two waypoints divided by time ) - 460 to 350 lbs per minute - actual figures came out between 440 and 320 with decreasing inflight-weight.Another mistake in the FMC : the fuel prediction on final at KSFO ( rwy 28L ) calls for 2300 lbs fuel-burn between OM and touchdown - actual was 900 lbs !! This mistake is noticable on ALL approaches !! In the RW flying the fuel-remaining figures remain nailed on the dot unless the past sector has produced significant differences - it is a real tool to watch the performance of the flight - the PMDG FMC is not ! ( So sorry ... - because otherwise the 747 is a real great sim-A/C !)I hope that the MD11 FMC will produce better results - I have a few hours on the real MD11 ( as an observer - my son is captain on this aircraft )and since my main interest in flightsimming is flightplanning and fuel management I had a specific eye on the FMC during our flights . . .GUESS WHAT WE ARE WAITING FOR . . . ?Karl, Berlin

Share this post


Link to post
Share on other sites

Hi, Johan:I just re-read The Good Captain's link you kindly posted. Man, it's sheer poetry--and poetry in motion at that.I miss his presence on the forums very much and miss interacting the way we did over the years.Happy post-Thanskgiving and Greetings for the upcoming Xmas season.Cheers,JS

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this