G-reg G1000 C182 why only night VFR (and not IFR)?

But no one would expect anything else if one of the attitude reference systems had failed.

Legal yes but you have to land ASAP if in IMC

Peter a unit such as a Mid continent SAM would give you a back up that meets the leagal requirements.

https://www.aircraftspruce.com/catalog/eppages/kellydualalternators.php

For sure ;)

For a single-alternator aircraft, a backup

This looks to defy logic, what does a vac pump give you with all the glass that is fitted ?

And in the “KINDS OF OPERATIONS EQUIPMENT LIST” in the C182 POH, there are some equipments you need to have for night IFR and not for night VFR (example : vacuum pump, Alternate static air source)

For a G1000, he’re a table (from the AFM) outlining the minimum requirements for Day VFR / Night VFR / IFR