Could you clarify this a bit? I'm assuming they're already legal for IFR as gyro replacements, are you saying the HSI function will be legal as a stand-alone?
Correct..as IFR replacements.. AI and DG only for now...
But the CDI, which will indicate when connected to a panel GPS, is not (yet) an IFR approved CDI.
The HSI function is not (yet) a legal stand alone, and cannot be used to replace a presently installed legal HSI.
Cap