You do not have to have a Flight Manual Supplement, TGL10 permits a compliance statement.
Doesn't TGL10 apply only to EU-regs?
Interesting... obviously one needs a Garmin x30/W or similar to get the LoA.
I am not aware of this requirement for an EHSI - where did this come from?
Travis posted it.
I never found any mention of it in the US "pilot hangouts" but then I wouldn't because the FAA grandfathered all N-regs with an IFR GPS to PRNAV compliance, in US airspace, and 99.x% of US private pilots never leave US airspace especially for anywhere where anybody knows what PRNAV is.