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G3X Emergency Approach Capability

RhinoDrvr

Well Known Member
***Below I?m asking about possible during an emergency, not necessarily legal***

In planning my G3X Panel for light IFR, I?ve arrived at the point of choosing an IFR Navigator, Com and Nav Suite. My primary method of Nav will be WAAS GPS from the GTN650. My only concern is that if the box fails, I?ll also lose my backup approach capability through the integrated Nav Radio.

I can split the two up via a GTN625, and a GNC255, but then it occurred to me that the G3X has a built in WAAS GPS. If I ditched the Nav radio completely, and lost my GTN in IFR conditions, is it possible (not necessarily legal) to load an approach into the G3X and get on deck with its built in WAAS GPS? That could save $5000 off my avionics cost. It also aligns my play airplane with my work airplane in that they would both be IFR capable with very little redundancy. :D

I understand it wouldn?t be a legal, but if it is a viable way to get safe on deck during an emergency I would feel okay forgoing the added weight, cost and complexity of a Nav radio.

As I understand it, a radio stack with just a G3X, GTN625, single Comm Radio and G5 would be legal for IFR since no backup for WAAS is required by the FAR?s, and if it I had to use the E word I could realistically get on deck with the G3X.

Is my thinking way off base?
 
IFR Backup

I personally think you would be fine with that. Also, since you have a G5 backup consider military bases in your area as most of them have PAR and SAR approaches that require you to have nothing but attitude information to recover in a bad situation. So if you lost both your navigator and GDU you could still recover on your G5 battery (unlikely except in a total electrical failure situation). You would need a radio for those approaches though. A simple handheld radio or even better a handheld Nav/radio at a fraction of the cost could accomplish that in an emergency if you are truly worried about a total failure.
 
Evan, I'm in a similar boat with all my legal IFR nav devices in one box. If that box fails, I have an ipad running Foreflight for charts/plates and also have backup charts/plates on my Skyview.

In an emergency where the GPS/Nav box failed and finding VMC wasn't an option, I wouldn't hesitate to first ask for an ASR/PAR approach as Jon mentioned if I was close enough to a facility with one. Failing that, I'd have no problem using ownship position depicted on an approach plate on Foreflight or Skyview, plus altimeter, to try and get down on a non-precision RNAV approach (about the best you can do with no glidepath/glideslope needles).

In an emergency, anything you have to do to get down safely is fair game.
 
I have kept the PAR/ASR in my back pocket, but I know more and more bases are going away from that capability. Seems Navy fields are more likely to have them operating than AFB?s in my experience.

I guess my last question is regarding the G3X user interface itself. Does the G3X allow RNAV approach waypoints to be loaded, or is there no ability to do that since it isn?t IFR certified by itself?
 
The G3X's built in VFR navigation system is almost identical to what you would get with a X96 or Aera portable GPS. You only get from the FAF to the MAP when you select and activate an approach. You could however build your own approach out of waypoints. You would also be able to view the GEO referenced Approach Plate as long as you had that database loaded.

Check out starting at page 190 of rev P of the Pilot's Guide.

In an emergency, everything is game to get you on the ground safe.

Another thing to consider is that while the GTN is all in one box, the internal design is modular. You have a separate main board, COM board, NAV board, and GPS board. The COM board input power is separate from the rest. From what I have seen, complete failures do not appear to be common.

I have experienced GPS board failures (once it was the board, once it was the antenna, and once it was a shorted antenna lead) and in all cases, the Main, NAV and COM boards continued to function fine.
 
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You sound committed to a G3X, which is fine. But the GRT HX/HXr has exactly what you are asking about. Currently in beta test, I think. Self contained (you need to add their $500 gps) full blown LPV approach capability.
 
You sound committed to a G3X, which is fine. But the GRT HX/HXr has exactly what you are asking about. Currently in beta test, I think. Self contained (you need to add their $500 gps) full blown LPV approach capability.

Just be aware that it may be great for emergency use but it is still not legal for IFR use...

From GRT:
"When complete, the approach option will be designed to meet the requirements of TSO-C129, TSO146C, but is not an FAA certified navigation source. GRT Avionics makes no claim regarding the legality
of using this function for intentional flight into IFR conditions for GPS approaches within the US or
foreign counties. Use of this function for GPS approaches in VFR conditions, such as for flight instruction,
maintaining currency, etc., is legal, as well as for use in an emergency per FAR 91.3."
 
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