Optimal flight evel - without FMS

[pawel-d 2]

Hi,Just starting my adventure with this bird. Fantastic aircraft from PMDG.I did some first flights, still learning.My question is about debriefing - how can I calculate optimal Flight Level for particular loud?I assume trip long enough so that we are not limited by short distance.I know I can see it on CDU after Weight Init, but I think it's more realistic to put it to flight plan before we get into cockpit. I always do it for other a/c.I thought it was function of gross weight, but when I started to play with different combinations of fuel and pax loads, I don't get "stright" results from FMS, so probably CG matters, or maybe some other factors should be taken into account.Any advise about it?Edit: sorry, mistake in topic, it should be Flight level.Sorry also for my english and other mistakes.--------------------Pawel Dragan

[Paul_Smith 92]

For the 747, you could look at the Cruise and Fuel planning document, page 9 which gives a table of optimum and maximum by weight. Unfortunatly, these figures were not published for the MD11.

[mbucholski 9]

It kinda comes with experience. Wyczucie.

[fumap 0]

You can do it by watching the performances tables that are missing in the PMDG MD-11...I was lucky to have some friends working on real MD11 in Malpensa, LIMC...;)Cheers,

[Paul_Smith 92]

You could also make your own table by setting up the FMC with different weights and recording the results. I havn't tried it yet but you might even be able to use step climbs to work out the burn through times.

[docjp 0]

Pawel,Maybe this will help?http://www.boeing.com/commercial/airports/acaps/md11sec3.pdfOtherwise I could recommend TopCat!Jan Peter

[fumap 0]

Pawel,Maybe this will help?http://www.boeing.co...ps/md11sec3.pdfOtherwise I could recommend TopCat!Jan Peter

This is a very intresting document that talks about Airport Planning about the MD-11The pages here are some of the document i'm speaking about.Unfortunatly, the MD11 performances tables are a secret document for an unknown reason.I recommand TOPCAT and maybe i suggest to go to the nearest airport served by an MD11 service, and talks to any pilot that walk around the terminal.Sometimes, that way gives me very nice opportunity, and a lot of helps. Some pilots are very friendly with FS/aviation enthusiasts...Cheers,

[pawel-d 2]

Thanks to everyone for interest and some ideas.I do use Tomcat, but I don't think it can calculate optimum flight level for cruise.I also don't have any airport around with MD-11 (I have EPGD a few miles from here, but md-11 don't come to us very often).What I'm gonna do is play more with load manager and FMS. I'll try to make tables of optimum flight level depending from fuel load for three passangers loads (those standard ones: 1/3, 2/3 and full). I'll see if it makes any sense then.I'll shere results with you.Regards,Pawel Dragan

[brian747 5]

I do use Tomcat, but I don't think it can calculate optimum flight level for cruise.

Hi Pawel!TOPCAT really is your friend. :( Although if you're talking "optimum", then IMHO there are two considerations that you may also wish to bear in mind — the first of which is straightforward, whilst the second..... isn't.1. The higher, the better (for fuel economy). Unless your TOC and your TOD get *too* close together, of course..... :( 2. It seems that you're inevitably going to be in RVSM airspace (FL290 - FL410) — in which case you really ought to take into account which country's airspace (or countries' airspaces) you'll be flying through. Just in case this is new to you, here's a very brief and condensed sketch of what I'm talking about (with apologies if you're already well aware of it).

Although most airspace uses westbound = even (i.e. FL 300, 320 ... 400) and eastbound = odd (i.e. FL290, 310 ... 410) rules, some countries (France, Spain, Switzerland, and others) use northbound = even and southbound = odd. However, in Italy this applies to

everything above 3000 ft.

— whilst in New Zealand they use their own version of northbound and southbound rules such that Northbound is Odd and Southbound is Even. :( And then you have the countries like China, Russia, and others that use metric units for their flight levels.....

So in a long international or transcontinental flight in your MD-11, it's quite possible that you will need to adjust your cruise level as you cross airspace boundaries to take those rules into account. It may seem like a lot to have to think about during your flight planning, but if you want to take your simulation seriously then you really need to do so to achieve "as real as it gets". B) Look, no one said it was going to be easy, right? B) Have fun,Brian

[pawel-d 2]

Brian,I think we are on the same page when talking about "as real as it gets". I'm aware of RVSM rules and take them into account during planning my flights.I wanted to have some reference about optimal (or maybe word "optimum" should be used ..?) and max flight levels depending on GW - to be able better choose FL when FL change is required by RVSM rules, to be able to calculate step climbs for longer flights, and to be sure not to make flight plan above limits.Anyway, I spent some time with FMS and produced some chart that I think can be helpfull. Please find it attached.It should be used only as rought reference (maybe some more factors, like for ex. CG, can affect the numbers), but yesterday I menaged to plan 2000nm flight with step climb, and all worked fine - I was able to plan and then perform my step climb at correct point.Pawel

[Paul_Smith 92]

Very nice!

[Guest dlrk]

Thanks!

[Guest cfgarrod]

I flew the MD11 for a European carrier, so all weights were in Kgs.We used the following 'rules of thumb':Max FL: 590-GW (GW = gross weight in Kgs)Optimum FL: 560-GWInitial cruising level:GW Max Opt Step280 330 300 310/290250 350 330 340/320230 370 350 360/340Chris G Switzerland