fmdc steps

[Guest pegasus60]

Hello all , Does anyone know of an easys to use guide for performing step climbs on pmdg 747 400 ? would be much appreciated if you can help .:-wave

[craig_read 43]

Hi,(you should sign your name, you'll get told off)...Step climb profiles are related to the weight of the aircraft you are flying. There are charts within the PMDG 747 manual that show you what the optimum cruise altitude is for the aircraft at a specific weight, and also charts that detail the rate of fuel burn at those weights and altitudes etc. Using both these charts you can work out a step climb profile of your own using perhaps 2,000 feet intervals.for example.. Say the aircraft weighs 800,000lbs and are cruising at FL320 (the optimum). The next step is from FL320 to FL340, the optimum cruise weight at FL340 is 760,000lbs (ish), meaning we need to burn 40,000lbs of fuel before FL340 is the optimum cruise altitude.. At the current fuel burn rate of around 28,800lbs per hour (I think that's right), it will take about 1 hour 20 minutes (40,000lbs to burn / 28,000lbs per hour burn = 1.38 hours..... which is about 80 minutes). You can then look at your route, and work out where you'll be after 80 minutes elapses from the point the aircraft weight is 800,000lbs. This will then be the point at which you initiate your step climb to FL340. Obviously this is very rough, but you get the idea.(I can't be sure of those numbers I did this quick and roughly)The FMC will do all of that itself, but I think when you draw up a plan it's not a bad idea to check your findings with what the FMC predicts. The FMC is an AID to flying, it is not the authority. When preparing to leave, you should have a route planned and noted, weather predictions, a step climb profile drawn up, known weights, your own fuel burn calculations, take off calcs, etc... If the FMC agrees with what you've calculated, then great, if not, double check your figures. But what the FMC gives you, shouldn't be too much of a surprise. I think it's always nice to go in with your paperwork, fire up the FMC and then enter all your data only to see it predicts pretty much what you had written down. You shouldn't be a million miles away, if there is some slight difference, then that's fine (50 miles here and there in profile difference, etc).Not sure if that helps....Craig

[basa 0]

>Hello all , > Does anyone know of an easys to use guide for>performing step climbs on pmdg 747 400 ? would be much>appreciated if you can help .:-wave 1.- Programming:PERF INIT page, right hand side.Step size, enter whatever you want (leave it with default ICAO 4000 ft, or enter 2000, or enter 0 if the flight is short enough).EXECute The aircraft computer will do all the calculations for you, distance and ETA will be displayed on the ND and PROG page.2.- Performing:At a certain distance before the programmed climbing point you will get a RESET MCP ALT warnig on the FMC.Select the new altitude rotating the MCP alt knob. Choose (if you haven't) how you want to get there ( VNAV, FLCH or VS ).

[Guest pegasus60]

Many thanks , Craig & Jose . Joe T