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G5 as altitude encoder

Rallylancer122

Well Known Member
Can the G5 be used as an altitude encoder for a Mode C/S transponder? Ok, I know it can technically, but I mean legally. My understanding is that the encoder needs to be TSO'd, and the G5 is not.
 
I have been using the G5 as my altitude encoder for ADS-B out for over two (2) years. The two G5s in my airplane passed my 91.411 and 91.413 tests with only needing a simple calibration.
 
same as Gary here... the PFD of my dual G5 install feeds alt to the GNX375. Works perfect :)
 
I like using the G5 as an altitude encoder when possible. It only makes sense in that it not only is a digital source, it also reads your altitude at all times in flight. Plus there is no added cost, weight or plumbing for a stand-alone encoder. That being said I had a G5 go haywire with about 20 hours since new and it started running the altitude from below sea level to 30k+ feet and all points in between randomly in a matter of seconds. The bird was departing the LA Basin and So. Cal approach got all in a tizzy with the altitudes being reported. Got the notice in the mail from the FAA ADS-B team and I had to write a letter stating I swapped out the air data computer with a loaner G5 and promised not to ever let it happen again if I could help it, I guess. I have never had a lick of trouble before or since with a G5.
 
Like I said, I know it CAN do it. Just wondering if it was legal. I know certain things still require a TSO (IFR navigators for instance) and I thought transponders and encoders was one of them.
 
Like I said, I know it CAN do it. Just wondering if it was legal. I know certain things still require a TSO (IFR navigators for instance) and I thought transponders and encoders was one of them.

When my RV-6 first flew, I use a Rocky Mountain Instruments microEncoder as my encoder. This was something that I purchased as a KIT and built myself. It was designed to meet the TSO and as such passed the 91.411 and 91.413 requirement every other year when my transponder was tested.
 
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