approach, and landing

[Clem Corky 0]

Hello everyone,

Im pretty new around here and I hope my question will not sound too dumb. 

I recently had a 747 v3 and I handle it as best as I can but I have an issue with my FMC i configured it normally with my route, departure airport arrival airport runways ... but my aircraft at one stage let say I'm level FL15 at waypoint A , and need to descend level FL10 at waypoint, well my aircraft will stay stuck at level FL15 but the speeds chance lets say i'm 250 at WP A and asked for 220 at WP B it will change.

 

I dont know what I configured incorrectly.

 

If you guys have any idea dont hesitate to let me know.

 

Cheers

 

Clement.

Edited December 12, 2023 by Ray Proudfoot
As requested the full name of the poster has been removed.

[Budbud 227]

Hi Clement,

The FD will command the change of level depending on the flight level in the FMCand the altitude entered in the MCP altitude box.

Look at your FMA to check in which pitch mode you are. 

Let's imagine in your case that your are proceeding from your position to the waypoint A with an altitude constraint of FL150, then waypoint B with an altitude constraint of FL100.

So if you start with a pitch mode of VNAV PTH or VNAV SPD in your descent and 15000 on the MCP, your aircraft will level off at FL150 and the pitch mode will change to VNAV ALT. In this case, if you just enter 10000 on the MCP, then the FD will still command a level off even if the constraint of the next waypoint is FL100. To continue the descent, you have to push the altitude button of the MCP.

However, in the same situation, if you enter 10000 on the MCP before the aircraft starts levelling off, then the pitch mode with remains VNAV PTH. The FD will command a pitch to pass Waypoint A at FL150 (even level off for while if needed) then continue the descent to FL120 once waypoint A is passed.

The key here is to understand how the system works and know where you are in terms of VNAV mode to know what to expect.

[Ray Proudfoot 8,931]

@Clem Corky, I have edited your post and removed your full name. I trust that is acceptable.