FMC FIX page

[Acesimulation]

I am wanting to do range rings but for some reason on the FIX when I go and put in the fix which in this case was RW25 for EGAA and it says not found ??? Works fine with the zibo ?

[Litjan]

I think it depends on the nav database read and if the runway ends are available. I don´t remember being able to input the runway ends on the 737, but we usually do nowadays on the A320, like EGAA25.

IIRC the FIX INFO can only take up to 5 letters, so EGAA25 wouldn´t be possible...

Not sure what database or FMC version the Zibo models, I don´t have it.

Cheers, Jan

 

[tkyler]

The only RW25 in the fix database (both old Aerosoft and latest Navigraph) is in EL SALVADOR, which is more then 3000 miles from EGAA.  As mentioned elsewhere, we cull the global database for only those waypoints that are within range of the aircraft when its loaded.  If we did not do that, then it would have loaded that fix, but it would have been the wrong fix anyhow and you wouldn't have seen it on the EHSI, which would probably have been even more confusing.

This culing technique saves quite a bit of memory and allows us to search the database much faster, avoiding potential pauses.  The fix page reads the fix database of the navdata.   I can't say if runway ends could be input in the older version of FMS we simulated, but I wouldn't be opposed to it, in the sense that even FMS software can be updated.  Its simply a matter of decideding if its a realistic feature for this simulation.  Jan?   The FMS manual we used only says, "valid navaid or wpt" and goes on to specifcally say,  "the FIX"....so we only implemented those navaids/fixes, which didn't include runway ends.

-tkyler

Edited May 27, 2020 by tkyler

[Litjan]

I guess if the navigation database holds the coordinates of the runway ends readily, I would have no objection to making them accessible to enter in the FIX page.

 

[Shifty]

I know on all of FMC's on the 300's we could put a runway fix in. I would always use it for putting range rings for some SA on approach. I Just get around it in the IXEG by using the Aerodrome in the fix instead. 

 

Regards

 

Craig 

[Rolandonavia1997]

I can agree on that, every -300 I’ve flown had the ability to put the runway fix in the fmc fix page, we usually do this In order to put our VDP ring for non precision approaches and therefore adjust a more precise vertical speed during the approach. (Make the altitude range arc appear on top of the ring arc on the ehsi, having set our MDA in the MCP obviously).

[Shifty]

10 minutes ago, Rolandonavia1997 said:

I can agree on that, every -300 I’ve flown had the ability to put the runway fix in the fmc fix page, we usually do this In order to put our VDP ring for non precision approaches and therefore adjust a more precise vertical speed during the approach. (Make the altitude range arc appear on top of the ring arc on the ehsi, having set our MDA in the MCP obviously).

Yeah, Gone of the 300 days....Just press Vnav now and drink my tea.

 

Although it did work until you wound up the missed approach alt 

Edited May 28, 2020 by Shifty

[Litjan]

VNAV work? No way!!

[tkyler]

OK, we'll put this on the list to implement then.

-tkyler

[Litjan]

After some consultation with Shifty we determined that the only runway related waypoints that can be entered in the FIX page are from the actual flight plan (i.e. what you can also find on the LEGS page).

So if you fly to Frankfurt (EDDF) and you have the ILS approach to runway 07C in your FMS, there will be a RW07C waypoint on your LEGS page. You can enter this one into the FIX page as any other fix.

You can NOT just enter RW07L at that point - only after you changed the approach in the FMS to ILS07L.

So we are going to implement it like that - only waypoints that you find in your LEGS page.

Cheers, Jan