Michael Adams wrote:
: What does the FAA say about adding IFR certification to planes which do not
: have it? Can IFR be added to any plane, or does it have to have some sort
: of "pre-cerfication" by the manufacturer for make and model? This question
: came up, because I have seen IFR added to a few aerobatic models, presumably
: for "emergency IFR". I know for helicopters, you can't add IFR unless it
: meets certain stability requirements. I wasn't sure about planes.

For certified aircraft it's probably in the TCDS. All that I have seen
specify a placard in the airplane that says something like "This Aircraft Is
Certified for the following conditions: Day - Night - VFR - IFR: If properly
equipped". (That was the placard language from a C-152, anyway.)

For homebuilts, well, the way it was explained to me by the friendly Van's
people is that the builder cerifies everything about the aircraft,
so they can specify anything they want, assuming proper equipment as you
noted in the reply below.
--
Aaron Coolidge