[attachment]foreflight.jpg[/attachment] [attachment]foreflight.jpg[/attachment] This past week I took a commercial flight from Atlanta to Bonaire (island 50 mi from Venezuela) which follows a course along the east coast of Florida, down the bahama chain, across Haiti then direct. As usual, I took my Ipad mini loaded with Ifly and Foreflight. I was using my Stratux with external antennae (antennae wedge in the window with clear view of the sky) to follow the route of the plane.
The only difference in this flight vs previous trips is that I used the Stratux for gps which can feed both Ifly and Foreflight.. Previously, I have brought the Ifly 720 with external antennae. The 720 usually lost connection about halfway down the bahama chain.
On this trip, I watched the flight from ATL down the Fla coast and everything was fine (both Ifly and Foreflight). Once I got out over the ocean in the Bahamas, the Ifly altitude began reading a negative altitude and hence set off alarms. The Ifly stayed in this mode all the way to Bonaire. I flipped flop back and forth between Ifly and Foreflight and determined that the Foreflight altitude was correct. I believe the distance to next waypoint and to final desitnation was correct on Ifly but the distance to next way point on Foreflight was not correct. I am not a power user for Foreflight and really hate using it so I may not be interpretting foreflight correctly. Ifly is 10 times easier to use
My confusion lies with the negative altitude in Ifly. On the return trip home, I observed the same phenomena with the altitude showing negative the entire trip from Bonaire to ATL. I tried recycling the Ipad, recycled and reloaded Ifly and even recycled Stratux.
Below are snap shots of both Ifly and Foreflight at about the same position over the bahamas between Freeport and Nassau.
Any clues on the negative altitude?