Title: GPS ALT on DATA/GPS MONITOR is affected by BARO setting

Issue:
The GPS ALT value displayed on the DATA/GPS MONITOR page changes when the BARO/QNH setting is adjusted.

Steps to reproduce:

1. Spawn on the ground at any airport and allow the aircraft to finish alignment.

2. Open MCDU → DATA → GPS MONITOR.

3. Note the displayed GPS ALT.

4. Change the BARO/QNH setting by a significant amount (e.g. ±20–30 hPa).

5. Observe the GPS ALT value.

Observed behavior:
The displayed GPS ALT changes as the BARO setting is changed.

Expected behavior:
GPS ALT should represent the GNSS-derived altitude and therefore should remain essentially independent of the selected BARO/QNH. Minor fluctuations due to GNSS accuracy are expected, but changing the altimeter setting should not systematically alter the displayed GPS altitude.

Additional information:
The same behavior has been observed on the A330, A310 and A340, suggesting it may be common to the shared avionics implementation rather than being aircraft-specific.

Edited 3 hours ago3 hr by jahtakesya