496 and g5 questions
 

Ok guys, we have some planes set up with G5s wired up to 496 gps units. The G5s will display horizontal and vertical guidance from the 496 units. I understand that the G5s can also use that data for attitude calculation if it is considered to be better quality than the internal GPS data.

First, is there a "best" choice for external antenna for the 496 since the mounting point causes the little factory stick antenna to not point straight up? Secondly, I don't think these 496s have been updated since the Clinton administration and I seem to remember the WAAS constellation changing some time back requiring a bunch of these older units to need some sort of update. Did that effect the X96 series units? The units always seem to be searching in vain for a WAAS lock. If an external antenna and/or firmware update get the WAAS function working, would that max out the G5 situational awareness, or should we consider also adding an external antenna to it as well? The G5 in this particular installation do suffer from rapid and fairly extreme maneuvering which causes them to go into in flight recalibration fairly often.

The G5 can accept GPS data for attitude aiding purposes from its internal GPS receiver, a GPS Navigator like a GTN 650, a GTX transponder with internal GPS receiver, or a GPS 20A. The GPSMAP 496 can not provide the GPS information the G5 needs for these purposes.

We suggest installing an antenna on the G5 and using the internal GPS receiver regardless of any outside GPS inputs.

Regarding the attitude re-calibration, please send us a flight data log from the G5 for us to take a look at, we should be able to narrow down the cause of the poor performance of this installation by looking at that document. Our email address is G3Xpert@Garmin.com, please feel free to send us a note if you are unsure of how to pull flight data logs off of the unit.

Thanks,

Justin