Long Range Pacific Flights

[skyymann 6]

Eric,I used a CI of 65 which gave me a M.841 cruise. Just landed at NZAA with 40K left.Scott

[Guest morvious]

3 Things though, because my Fsbuild comes with an accurate fuel number.1: Did you select "Step climb profile"? Take a look at the altitudes fsbuild says you are flying with!!2: What B747 airplane do you select in fsbuild?3: FSbuild can do some strange things with flightplans that are imported, look carefully at your flightplan in fsbuild. Sometimes it changes waypoints and fixes, so the route is longer then it actual is.And, there are easy B747-400 fuel calculators on the web, that can do the same thing as fsbuild, like people mentioned before.Cheers,---------------Stefan van Hierden>|

[Guest Vagabond78]

>1: Did you select "Step climb profile"? Take a look at the>altitudes fsbuild says you are flying with!!I have checked the option in FS Build for step climb however even if I tell FS Build to use a cruise altitude of 41000 FT it keeps giving me an inital cruise of 31000 and a final of 35000. Is this correct for a step climb? I thought that the flight plan should reflect 2000FT steps up to FL410, maybe this is my problem?>2: What B747 airplane do you select in fsbuild?PMDG 744 from the FS Build website.>3: FSbuild can do some strange things with flightplans that>are imported, look carefully at your flightplan in fsbuild.>Sometimes it changes waypoints and fixes, so the route is>longer then it actual is.Ok will check this out.>And, there are easy B747-400 fuel calculators on the web, that>can do the same thing as fsbuild, like people mentioned>before.Yeah I have these and they are coming up with similar numbers as FS Build. i.e. More than the maximum possible in the tanks. I sure wish I could get a hold of some charts that are for a lower cruise speed for the fuel calculation. I know they are out there. :)(For the reply below this)Scott, I really do believe you about being able to make the flight. I just want the numbers to make sense and also for myself to better understand the process. Intuitively I know that I would be able to make a longer flight if I did not cruise at M.86 and used a lower value such as M.80 or M.84, but I would like to be able to calculate it correctly also ... sorry I'm an engineer. :(Thanks for the help.

[Guest]

there is no such thing as a -400 to my knowledge, the different dash numbers are different engine variants, and the 438 is the ER variant

[Guest Vagabond78]

>there is no such thing as a -400 to my knowledge, the different dash numbers are different engine variants, and the 438 is the ER variantAhh I see, so do you know what variant the GE model is that comes with the Queen?

[Guest Soulman]

>>there is no such thing as a -400 to my knowledge, the>different dash numbers are different engine variants, and the>438 is the ER variantYou will find the '4' is obviously the variant, in this case a '400' series. The '38' significance is it's affiliation to Qantas. It does not suggest that it is an ER model. Qantas have both B747-438's and the more recently acquired B747-438/ER.You will notice Qantas also have the following aircraft with a '38' designation:B767-338/ERB737-838A quick search of airliners.net will show you this. Think of it as an airline specific code - it comes from Boeing.Check Singapore for example - they have '12'. B747-412, B777-312, B777-212/ER.I hope this helps.

[Guest Boeing747-430]

ya, for boeing, the dash number is airline specific, UAL has 22, DL has 32. i think i read somewhere that for airbus the dash number is engine specific.adam

[Guest Vagabond78]

Ok, I thought you were crazy at first ;) because I saw on airliners.net that Cathay Pacific was operating a -412 but then I saw it was purchased from Singapore Airlines. It looks like the acutal Cathay Pacific designation is -467. So is it safe to assume that besides the fact that PMDG is simulating the GE engines and Cathay is using RR engines that the performances are almost identical? i.e. These are not ER's I see on airliners.net that the GE's are more fuel efficient than the RR's.

[Qavion 19]

QANTAS has always had problems with this route and have been limited to the amount of cargo/pax they can carry (especially on the even longer YMML/KLAX/YMML run).This is why the ER was introduced into the passenger fleet. The ER has an auxilliary fuel tank in the forward cargo area. Cockpit shots of these aircraft will show additional switches on the overhead fuel panel for using fuel in the Aux tank. The EICAS fuel synoptic has also been modified. http://members.ozemail.com.au/~b744er/744e...ferOnGround.jpgThere are also many many other modifications to the ER version.Having an Aux tank doesn't make 100% sense to me though... the fuel tank takes up space which would otherwise have been used for cargo. Either way you lose some cargo carrying capability (volume, if not weight).the -438 designation is just a company thing...not an aircraft type. 38 = Qantas, 36=British Airways, etc...I found it quite amusing when someone recently posted a message on the old forum saying that he was 99% sure that an ER version did not exist (after having worked on them for a few years) :( Cheers.Q>

[Qavion 19]

"there is no such thing as a -400 to my knowledge, the different dash numbers are different engine variants, and the 438 is the ER variant"Almost all of Qantas' 747-400's are -438's. The -438ER is the extended range type. The fact that it has GE engines is co-incidental. All Qantas Boeings have -x38 designations (apart from those aircraft acquired (second hand) from other airlines, such as the RR-powered 767-336's... formerly owned by British Airways). Again, this is co-incidence that they have different engines to the other 767's... which had GE's and P&W engines. -x38 simply means it's a QF aircraft. 38 is a Boeing customer number.But, hey, what would I know... I've only been working on QF aircraft for the last 30 years :(Cheers.Q.P.S. (Edit) BTW, don't believe anything you see written on the side of airplanes... Our ER's have "747-400ER" written on the fuselage just to confuse the issue.

[Guest Vagabond78]

Hi Q,Just for my own understanding, Qantas did not fly this route with a full load of passengers prior to the ER or are the still not able to take a full load of passengers?Also have you ever seen the alternate fuel planning chart that I have spoken of above? If so can you describe it to me a little please?Thanks for all the help.

[Qavion 19]

"Qantas did not fly this route with a full load of passengers prior to the ER or are the still not able to take a full load of passengers?"They, of course, tried to offload cargo before passengers, but I seem to recall that there may have been occasions when they had to offload pax, too in certain circumstances.It usually depends on weather conditions... and it is always more critical in one direction than the other. The ER has improved the situation, but unexpected winds and maintenance problems can still cause hiccups.E.g. if the TCAS system failed, you wouldn't be able to operate FANS routes, so you wouldn't be able to choose the best route (to take advantage of the best winds).Sorry, I haven't seen the charts (not quite in my line of work).Cheers.Q>

[Guest Vagabond78]

Thanks Q, as usual a very informative post. What is your line of work with Qantas if you don't mind my asking?Also maybe the Queen's designers could add a little to this thread as far as the other charts are concerned, or long range fuel planning in general. :)Cheers,Erichttp://www.precisionmanuals.com/images/forum/747400.jpg

[Guest morvious]

>>1: Did you select "Step climb profile"? Take a look at the>>altitudes fsbuild says you are flying with!!>>I have checked the option in FS Build for step climb however>even if I tell FS Build to use a cruise altitude of 41000 FT>it keeps giving me an inital cruise of 31000 and a final of>35000. Is this correct for a step climb? I thought that the>flight plan should reflect 2000FT steps up to FL410, maybe>this is my problem?>You can enter FL410, but when FSbuild thinks you are to heavy for FL410, it will automaticly calculate what FL you can reach on that route.(When you hit the build button in fsbuild, you will see it wil start calculating at FL410, then FL390 etc etc)There is also an option in FSbuild to get RVSM levels (you can select it somewhere below the stepclimb option). So instead of steps of 4000, it will give you 2000, maybe FL370 or even FL390 can be reached then to safe some extra fuel!

[michal 44]

I just may add - although it had already been stated before that for long haul flights knowledge of winds and finding wind-optimal routes is of critical importance, specially when you are flying in the westerly direction. I once visited an Oakland Center and was shown a special station devoted to advising pilots/airlines on wind-optimal routes across Pacific. I was completly blown away how winds could affect preferred trajectories. I could see on a big screen how winds could make a flight follow a path that was almost 25 deg (!) further south than its more typical route. Typically during winter months the problem is more critical since jetstreams are stronger then.Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://www.hifisim.com/images/asv_beta_member.jpg