A320 FMS altitude constraint in white

[Check Airman]

Question for those in the know. What does a white altitude constraint mean in the MCDU? I entered an altitude and upon inserting it, it was green, with a purple asterisk. So far so good. When I changed the altitude to a higher one, the asterisk remained purple, but the altitude was white. We also go the -TOO STEEP PATH- right below the line with the constraints.

Couldn't find it anywhere. Does anyone have an answer with a reference? Thanks

[neilki]

Question for those in the know. What does a white altitude constraint mean in the MCDU? I entered an altitude and upon inserting it, it was green, with a purple asterisk. So far so good. When I changed the altitude to a higher one, the asterisk remained purple, but the altitude was white. We also go the -TOO STEEP PATH- right below the line with the constraints.

Couldn't find it anywhere. Does anyone have an answer with a reference? Thanks
Which FMS OEM?
9E Alum?

[iceman50]

Was this on the approach? Going white possibly means the FM cannot work out the descent profile which is why you had a too steep path as it cannot work it out from the without knowing the a/c speed. Sometimes setting Vapp at the FAF removes the too steep path, as the FM needed to know what speed at that constraint.

[sonicbum]

Question for those in the know. What does a white altitude constraint mean in the MCDU? I entered an altitude and upon inserting it, it was green, with a purple asterisk. So far so good. When I changed the altitude to a higher one, the asterisk remained purple, but the altitude was white. We also go the -TOO STEEP PATH- right below the line with the constraints.

Couldn't find it anywhere. Does anyone have an answer with a reference? Thanks

I am not sure why the asterisk remained purple as it should have turned amber since the constraint was missed in association with the white altitude. Were You in OP DES ?

[Check Airman]

Was this on the approach? Going white possibly means the FM cannot work out the descent profile which is why you had a too steep path as it cannot work it out from the without knowing the a/c speed. Sometimes setting Vapp at the FAF removes the too steep path, as the FM needed to know what speed at that constraint.

It was on the STAR. The only constraint, apart from the approach waypoints.

[Check Airman]

Which FMS OEM?
9E Alum?

Not sure which fms we have. 9E being Endeavour? No

[Check Airman]

I am not sure why the asterisk remained purple as it should have turned amber since the constraint was missed in association with the white altitude. Were You in OP DES ?
The circle around the constraint on the ND was purple. That was normal. I'm talking about the digits on the MCDU itself being white. We were in the cruise phase, well before top of descent.

[neilki]

Not sure which fms we have. 9E being Endeavour? No
Thales and Honeywell have several differences, I had a good look through the Honeywell FMS guide and didnt see anything. Clearly she thinks she can’t make the constraint, but i’d like to find out too...

[Check Airman]

Thales and Honeywell have several differences, I had a good look through the Honeywell FMS guide and didnt see anything. Clearly she thinks she can’t make the constraint, but i’d like to find out too...

It made the constraint fine. We fly that STAR every day, and like I said it was the only constraint outside of the approach, so there was nothing preventing it from making it.

[FlightDetent]

Which FMS - at least the supplier, if not the version?
Which constraint, hard alt, or alt+ ?

Either way you have created a vertical discontinuity, the FMS believed it is impossible to rejoin the calculated path due to your CSRT being too high. As a consequence, the last ALT prediction before the discontinuity, the altitude of the constraint itself, was displayed in white instead of the traditional green colour. <---- is that it?

[Check Airman]

I think it's Thales. No idea which version.
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/1099x1280/img_20190907_wa0100_05c1fdf8c97e411f5a2319f430700c99cd526ed5 .jpg
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1059x1280/img_20190907_wa0101_94c404befd5f79a06b90698f05f37516e4d5ed6c .jpg

[sonicbum]

I think it's Thales. No idea which version.
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/1099x1280/img_20190907_wa0100_05c1fdf8c97e411f5a2319f430700c99cd526ed5 .jpg
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1059x1280/img_20190907_wa0101_94c404befd5f79a06b90698f05f37516e4d5ed6c .jpg

Yes, it's Thales.

THALES FMGC GUIDE (http://www.smartcockpit.com/docs/Smiths_Thales_A_1_0_1_FM_Pilot_Guide.pdf)

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