Does anyone know if there Is a "relationship" between programmed step climbs and the opt/max flight levels presented by the FMC? The reason I ask is as follows: I program a number of cruize levels at "init" phase and hold at each flight level by using altitude, as I think is described in the manual. However, I notice that (according to the flight plan) the FMC keeps on wanting to push the flight level higher than the flight level shown as OPT in the performance page of the FMS. Any input would be gratefully appreciated, even if it is to point out to me I have being doing it wrong all these years. Regards Stuart

The plane will want to step climb whenever the next flight level is the next optimum one. Whenever you are done with the preflight and done setting up the fmc, look at the INIT page and note the optimum altitude. Start your initial cruise altitude with that one unless you have restrictions, and set up step climbs for every 2000 feet. So if it says the optimum is 335, then start with 340 (or 330 depending on direction of flight), and type 340/360/380/400 to insert into cruise altitude on init page.

 

Now when you start flying, you can set your altitude selector to 40000 and the plane will climb to 340 and step climb automatically to fl400 if you use profile mode. It does this based on optimum, and not maximum, cruise altitudes. So when you're flying and the optimum changes to 350, it will climb to 360 until the optimum becomes 370, where it will climb to 380, and so on.

It's realistic. When I flew heavies(C-141/DC-10), We would climb to 2000 above optimum and stay there until 2000 feet below it. This keeps you in the optimum zone longer while reducing climb fuel. We would only step climb when fuel was a factor. Normally we flew our planned altitude. If heavy, we would step until reaching our planned altitude.

Thanks for taking the time to provide the answers, much appreciated. It would appear I have sort of being doing the planning right but not quite the execution. From now onwards I will make sure the first cruize level programmed is equal to the opt shown on the init page and then program remainder step climbs at 2K intervals until planned altitude. Once again many thanks. Regards Stuart