Look guys, I understand your point about panel vs portable; WAAS vs non-WAAS, 3D vs 2D, and how dangerous it is to use something portable for something critical. I really do. And I'm familiar with RAIM. Since my 430 is non-WAAS, I have to do a RAIM check before every IFR flight in order to be legal to use it for an approach. Here's the thing: Every article I've read on ADS-B traffic, certified or not, says not to rely on it . Yet there is is, available for use on the iFly at the pilot's discretion. If you've been here long enough you know that iFly didn't "enable" WAAS on its units for a long time because it's not a "certified" WAAS GPS, yet now it's available for us to use in all its uncertified glory. The Alt (MSL), Alt (AGL), and Vert. Speed instruments all rely on the altitude function of the GPS to compute a number, inaccurate as it may be. Yet there those instruments are, available for our use. Can you believe some people even use their iFly to drive an autopilot? Talk about a leap of faith; those guys are real daredevils! Or are they? Maybe, like me, they understand and accept the inherent risks in owning a non-certified device. For the record, I've been known to forget to bring the iFly and was still able to complete a flight using only the panel of instruments I've been using since 1992. I wouldn't rely on an uncertified tape to tell me when I've hit minimums any more than I'd rely on a canary to let me know there's carbon monoxide in the cockpit. But IF I had a canary in the cockpit, and IF that canary suddenly went toes up, I'd immediately open a window. And if I'm minding my own business or fixated on a missed procedure in the clouds and a tape tells me I'm getting low, I'm gonna immediately arrest any descent and verify my altitude with certified instruments. I'm still firmly convinced it's a good idea (Hardheaded, Party of ONE!). However, y'all have given me some additional ideas for improving the tape. Make the background green if there's a WAAS signal, yellow if it's regular GPS, and faded/inop if there's no GPS signal.
Sorry this got so long-winded; I had some time to kill. In my opinion iFly has the best product on the market and I want it to stay thay way.
And to clear up what I think is someone's misconception about the orbital position of GPS satellites, here is a pretty neat animation:
http://en.wikipedia.org/wiki/Global_Positioning_System#mediaviewer/File:ConstellationGPS.gif