Hello all,

Please help me out. Below is the flight plan (courtesy of PFPX V2) I will be referencing.

N0510F320 OPAMO6 VAGPU Q8 AGELA B466 BBB/N0509F310 A347 ISRIS/N0506F330 A347 APANO/N0509F320 G208 KE B210 NH J115 KALAT N636          PAMTU/N0497F340 B411 MSD G775 ORPAB B450 MARAL/N0487F360 M23 BISNA B491 MKL B494 OLGIN M991 NIROV L984 DONAD L602 SOPGA T170          LATBA/N0428F220 T170 GAPLA T178 KERAX KER25S

I highlighted two positions where enroute descent is to be performed. My question is, how do I enter these enroute descents in th FMC? If it's a step climb, I know I enter data such as 330S for example. But if it's an enroute descent then what format should I use? Or should I simply choose not to enter it at all?

Any help is appreciated.

Edited February 12, 20197 yr by kityatyi

Simple - just insert the lower cruising altitude in the MCP ALT window and push the Altitude selector so that it then becomes the new active cruise altitude without creating a modification and the aircraft will descend in VNAV mode. However, when the aircraft is within 50nms of the T/D position, or if the MCP altitude is set below the highest descent altitude constraint in the VNAV descent profile, then selecting an altitude below the current cruising altitude and pushing the MCP altitude selector will activate the DES NOW function.

Thanks, done, all good!

Turn off Optimize FL in PFPX plan it has some false step climbs. IRL atc if you need an odd level gives you up or down depending on traffic - David Lee

19 minutes ago, Boeing or not going said:

Turn off Optimize FL in PFPX plan it has some false step climbs. IRL atc if you need an odd level gives you up or down depending on traffic - David Lee

David,

Do you remember where this option is in PFPX?

Not a false step climb/descent but related to the direction of flight on the airways and optimum cruise level.

The despatcher can easily adjust this using the Speed/Altitude/Holding functions on the advanced planning screen to ensure an upward direction.

 

For proper fuel and time planning do not wait to just enter the new altitude in the MCP if the step size is set to "0".  A step is a step whether it's a climb or a descent.  So if you initial cruise is set to FL330 but you are going to buck a crazy headwind at that altitude and PFPX has determine a step descent is needed for optimum fuel burn them just enter 310S at whatever fix is needed. I'd you fail Todo so you might get misleading Insufficient Fuel messages.  The fix in all this is either program all your steps both climb and descent or leave the step size in ICAO/RVSM or some other programming you prefer.  The is all predicated on you loading enroute winds also I should add.

4 hours ago, Olympic260 said:

David,

Do you remember where this option is in PFPX?

- David Lee

25 minutes ago, Boeing or not going said:

- David Lee

Thx 🙂