Everything here is from the references shown below, with a few comments in an alternate color.
The following checklist should be conducted at regular intervals during cruise phase of flight.
FMS fuel quantity should not be updated in flight. The FMS fuel quantity is an independent information source provided to verify FQMS quantity and assist troubleshooting FQMS indication errors or fuel leaks.
Displayed PFD altitudes automatically change from the selected ADS to a Voted Altitude at approximately FL280. The HUD continues to display the selected ADS information at all times.
Above FL280 there may be displayed altitude differences of up to ±150 feet between the HUD and PFD. The PFD altitude should be considered the most accurate.
Gulfstream GVII-G500 Airplane Flight Manual, Revision 4, August 29, 2019
Gulfstream GVII-G500 Production Aircraft Systems, Revision 3, July 15, 2019
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