Lately the subject of flying IFR (Instrument Flight Rules) has occupied my time and more than a few pixels on this website. The debate centered on flight into IMC (Instrument Meteorological Conditions… or situations with no or low visibility, or simplistically, flight into clouds). Although I spend 100% of every day on the subject of Light-Sport Aircraft and other flying machines used for aerial recreation, I can also make mistakes explaining all the ins and outs of the six-year-old regulation abbreviated as SP/LSA. I corrected my last SPLOG post on this subject, but I enlisted Robert Hamilton of Dynon to help further. Robert had politely explained to me that I’d made an error. Rather than tackling this myself, I asked him to contribute. *** From Robert… “At Dynon we are often asked if our avionic products are ‘Certified’ for IFR flight. In fact, there is no such thing as ‘IFR Certification’ for amateur-built and LSA aircraft, and so answering the question requires an explanation. *** “The relevant regulation is FAR 91.205, which lists equipment that is required for various types and times of flight: VFR, VFR Night, and IFR. Included for IFR flight are such things as two-way communication and navigation equipment, gyroscopic rate-of-turn indicator, sensitive altimeter, artificial horizon, etc. Most modern digital glass panel avionics meet these requirements for the analog gauges they replace. Interestingly, the definition of ‘gyroscopic rate-of-turn’ is based on functionality, and so includes solid-state MEMS (micro-electro-mechanical system) devices which are used in most digital, solid-state AHRS (Attitude Heading Reference Systems). There are many thousands of home-built aircraft legally flying IFR with ‘non-certified’ Dynon digital avionics. *** “Does this mean a Light Sport Aircraft with the same digital avionics is IFR legal? The answer to that question must come from the ASTM F37 LSA committee and the aircraft manufacturer. Assuming a LSA is equipped to meet the requirements of FAR 91.205, the avionics equipment is not a restriction. However, the overall aircraft operating limitations are specified by the manufacturer according to the standards written by ASTM committee members and subsequently accepted by FAA.” *** Hopefully Robert answered the question, but as I’ve noted earlier, this is not likely the end to the vigorous IFR/IMC discussion.