Hi Gil,
...sorry for the mis-read...
No problem. Been there, done that myself more than once!!
But, that would make it even harder (just about impossible) for any regular home builder to "document compliance with the appropriate standard".
Agreed. The article does not mean to imply that any of this would be easy, or even doable. But it would be legal if the person wanted to go through the effort.
Why not just come out and say directly that a GPS system must be TSO'd for use under IFR? - if used as a primary navigation function, not a situational awareness function.
Because if the article said that we'd have a bunch of people writing and calling, telling us that the article is not accurately stating what is legal and what is not! This happens all the time to us here at EAA HQ. There are a fair number of folks who read our publications and then go to great lengths to take issue with anything that is not absolutely accurate. This is not a bad thing, but trying to satisfy those folks leads us to situations like this discussion, where what is technically legal does not necessarily make a lot of sense. It really can be a "no win" situation sometimes when posting and publishing info. Everyone has their own opinion on what we should say and how we should say it. Bottom line: We do the best, most accurate job we can and deal with the feedback as it comes.
Again, I say read a few sections of the actual TSO C-129 I linked to previously and ask yourself "can I honestly document that my 496 (or any other non-TSO GPS system) meets the requirements"?.
I agree. I don't think anyone could do it, and I don't recommend anyone actually go to the effort of trying. In fact, I have some doubt that you could actually meet the requirements of the TSO with a 496. But if anyone really would like to try it, they're welcome to!
The FAA has nicely limited the amount of equipment that must be TSO'd (or documented to the TSO requirements) for our Experimentals - it's easier to just buy that equipment, especially for something as important as IFR flight.
Amen to that! I totally agree. And that's exactly the way 99.9% of the people do it. It's by far the most economical way to equip the aircraft. And that is mentioned in the article.
I still say the article is an over-simplification.
That may be the case, and you're certainly welcome to that opinion. But the article is technically accurate, as far as we are able to determine. I hope most find it to be informative and useful.
Cheers!
Joe