FMC waypoint speeds reduced as we progress.

[RynardtSpies 1]

HI,

 

I am currently flying from EGLL to OBBI and since departing I've had to battle an issue where the next 1 or 2 (sometimes more) waypoints have their speeds set to 170kts in the FMC. I am le currently at FL350 and have set the MCP speed to .83mach. If I leave it on FMC speed, the aircraft slows down to the slowest possible safe speed, just above stall as the FMC sets the speed to 170kts.

 

Now, this happens as the flights progresses. For example, in the FMC I can see that my waypoints currently are:

 

BOREP 170/FL369

BAMAS 170/FL381

KEPOM .828/FL390

 

Now, when the aircraft reaches BOREP, KEPOM will be altered to read 170/390.

 

I have read the introduction manual and have been through the FCTM and FCOM 1&2.

 

If it helps, I'm flying with a cost index of 72.

 

Any ideas?

 

Rynardt

[downscc 1,327]

170 happens to be the speed that the FMS sets at the runway. Maybe a screen shot would help, actually sounds like you have a configuration problem (flaps).

[RynardtSpies 1]

This is strange, cause flaps is up...

[scandinavian13 5,192]

 

 

Any ideas?

 

Did you import this flight plan from somewhere?

[RynardtSpies 1]

Hi,

 

Yes imported from VROUTE. This has not been an issue on any of my previous flights, but it did actually cross my mind whilst troubleshooting.

[MTN1289 31]

When ever I get strangeness like this, I just manually fix the issue. Just go to your LEGS page and type .828/, then execute. 

[RynardtSpies 1]

 

 

When ever I get strangeness like this, I just manually fix the issue. Just go to your LEGS page and type .828/, then execute. 

 

Tried that, I just get "INVALID ENTRY".

 

I have recorded a video of my issue, uploading it now.

 

It probably is the flight plan import that has caused the issue.

[scandinavian13 5,192]

 

 

Yes imported from VROUTE.

 

Try it without VROUTE.

 

For what it's worth, it's really not that difficult to manually type out routes.  If you plan on flying the same route again, there's a save prompt on Page 1 of the RTE pages.  There's no better source than the origin (which is what's going to be reading the route file in the end anyway).

[RynardtSpies 1]

For now I'll just have to fly the flight as is. Once landed, I'll try it again with a manual flight plan entry and update this post with the results.

 

Here's a short video of what I'm getting:

 

http://youtu.be/jl91jeP7IGI
 

Rynardt