Hi Pete;

My understanding of what "IFR Certified" means in regards to an aircraft is that it has the minimum equipment required for IFR operations, and has had the appropriate inspections to insure the airplane and equipment are safe for flight. That can be determined by examining the equipment list for the airplane and the logbook entries, but there is no logbook entry that says "IFR Certified".

The FARs specify the minimum equipment required, to include the instrumentation, avionics, and the other aircraft systems required.  The 24 month pitot/static and transponder test certifies that the airspeed indicator, altimieter, and altitude encoder is working properly and is reporting the correct altitude to ATC. The 30 day VOR check insures that these navigation instruments are accurate enough for safe flight. The annual inspection is supposed to insure that all the other aircraft systems are safe for flight.

As far as the avionics, the FARs only require radios and navigation equipment appropriate for the operation. A single Nav/Com with a VOR indicator may meet the minimum requirement for enroute and some localizer approaches. A VOR with a glideslope indicator is required for ILS approaches, along with a marker beacon receiver to identify points along the approach.  DME or ADF are required for some approaches and holding operations, and an IFR certified GPS can allow you to perform other types of approaches and direct enroute navigation.

So as you can see, there is a minimum requirement that is specified in the FARs, and the rest is more of a limiting factor as to what types of IFR operations you can perform.  That is why you give ATC the equipment suffix when you communicate with them or file a flight plan.  That way they shouldn't give you an instruction that requires equipment you don't have on your aircraft.

Hope this helps.

Jon

Hi Pete:

As a follow up, the required equipment for IFR is specified in Part 91, Section 91.205 of the FARs.

Jon