On the SR22 I believe the EHSI has a back up power supply. That would keep this instrument operating with power off? Larry
On the SR22 I believe the EHSI has a back up power supply. That would keep this instrument operating with power off? Larry
Larry: I don’t recall anything to this effect in the Sandel installation or operating manuals. Even a back up power supply to the Sandel wouldn’t be of much use anyway, since the unit is dependent on the Garmin 430 for position data and on the gyro for heading data and both of these are dependant on power to operate.
I think that the safest provision for the total electrical failure is to put in the BFGoodrich 2 1/4" AH and provide for a backup battery for it in the same manner as the Piper Meridian. The only problem is where to put the instrument. The best location is a replacement for the Davtron clock/oat/voltmeter. However, since the Davtron unit is described in the POH, there is an issue as to whether you could get approval for removing it and replacing it with the backup AH.
If Cirrus offers the Shadin 200 air data computer, the outside air temperature will display on the Garmin along with calculated air data, wind vectors, etc. There are probably sufficient clock displays between the Garmin transponder and the 430. I don’t think that the Shadin 200 will display voltage.
It is all up to getting FAA approval on the change.