Maximum Crz Alt

[RDG41 1]

I'm just wondering if there is a way to calculate the Max CRZ altitude or a program that will do it for me instead of letting the FMC figure it out, then tell me it's set too high. This is in regards to the 747 for FSX.Sometimes I reset it to the FMC's requested level, then it will tell me this is too high and I have to reset it again.Thanks for the help.

[cshark172 20]

RTFM -- The manuals have charts with Maximum/Optimum Cruise levels for different Gross Weights.KyleFS box: Q6600 (@ 3.24 GHz), ASUS P5E3 Premium, 4 GB OCZ Platinum DDR3 (Cas 6-6-6-18-2T @ 1440 MHz), BFG 8800GTX 768, Soundblaster XFi Fatality, WD 300 GB 10000 rpm VelociRaptor (FSX), WD 150 GB 1000 rpm Raptor (FS9), Samsung Spinpoint F1 750 GB (OS/Apps), Silverstone TJ09 case, PC Power & Cooling Silencer 750 PSU, Vista Ultimate 64WideClient1: An old P4 with 1 GB ramWideClient2: Compaq Presario Laptophttp://www.precisionmanuals.com/images/forum/747400.jpg

[RDG41 1]

I've RTFM but still seem to get this popping up once in a while.

[craig_read 43]

When you say it tells you.. what exactly do you mean? ... You're getting a message saying "UNABLE NEXT ALT" ? Something like that? The FMC should calculate your step climb profile accurately every time, you can look in the progress pages and VNAV pages to determine when your next step should be, and also you can set the increment manually..Could you clarify what exactly is happening here? Should be able to help you out then..CheersCraig

[RDG41 1]

Hi Craig,What I mean is, when I set the crz altitude by the suggested altitude for my weight, I sometimes get a message ( sometimes not till I'm off and climbing) that the Max cruise altitude that I have set is not achievable. When I reset it to just below what it is suggesting, it will sometimes come back and say this is not achievable. Usually once I reset it a second time, it's ok. It doesn't happen all the time. I haven't tried to use the step climb yet as I usually don't have the time to sit there and watch it climb so I usually set the MCP for my set crz Alt which seems to work for me most of the time.

[BAW9DV 2]

Hi,Probably the best way to actually see if your selected cruise level is "achiveable" is to complete the FMC programming first. Make sure you go right through to the V-Speeds page and select each V-speed and the trim angle to confirm them all.Ensure you have completed the required entires in the VNAV page, entering all the required information to allow the FMc to do its work - then go to page 2 of the VNAV page. It should show you the OPT LVL or the achievable level for the weight that you have. Lastly, go to the PROG page to check details there (it will give you an idea of your next step climb - again, assuming that you have set the appropriate mode of climb - ICAO/4000 feet for non-RVSM airspace or 2000 for RVSM airspace)In the FS9 version, I have found that often setting a level about 2000 feet lower than the OPT LVL shown on the FMC VNAV page 2, works better in the simulation. Not sure about FSX, but for me this avoids getting too close to the "barber pole" as you get higher. Also, if you use real weather (ActiveSky X for example), there may be better winds at a lower level which might influence your choice of cruise.Take care,Lee

[RDG41 1]

Hi Lee,Thanks for the in depth response. You clarified some things and brought my attention to some things I overlooked.