Asking for a friend......
’86 M20K, had a Aspen EFD1000 Pro installed; no additional battery besides the internal. This replaced vacuum-driven King KI-256 ADI and a KI-55 HSI. Since these were the only remaining vacuum-driven items on the plane, vacuum system was removed. Legacy airspeed, altitude, and turn coordinator were all retained. A G5 was installed as a backup attitude source.
Now learning this may not be a legit installation because the STC for the G5 doesn’t allow its use as a backup attitude source (the G5 apparently isn’t TSO’d in this installation; only TSO’d as the backup to a TXi), and the STC for the Aspen installation requires a TSO’d backup attitude.
My question—Has anyone gotten a field approval for this (or a similar) setup?