Originally Posted by DylanRush
Ah good points. It does seem nutty to replace my current GPS with an even older GPS. So the TSO would only cover certain CDIs or annunciators and the Skyview couldn't do that?
Strictly speaking, the TSO covers everything - antenna, indicators, panel placement, etc. But the FARs don’t say ‘TSO’, they say ‘approved’. And while so far, the faa has not approved a main gps box unless it is TSO’d, they seem content to let EAB aircraft use indicators, etc., that satisfactorily perform the same function as the TSO’d units. So short answer, yes, the Skyview CDI/HSI can be used. It can also replace annunciators if it can replicate the approved ones. Many builders have mounted antennas not in compliance with the TSO’d installation instructions (which personally I think is a bad idea) but so far the FAA has been silent. BTW, unless the rules have changed, you can continue to use your existing gps even with an expired database for enroute only. You’re supposed to check that you have the needed waypoints, and that none have moved.