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GNC300XL Instrallation Certification Question

edclee

Well Known Member
Patron
The question is, does the GNC300XL installation, which replaces my GNC250XL have to be certified by an avionics shop for IFR use or can I determine it is accurate and properly functioning by testing the installation myself in an experimental? Has anyone else done this?
Ed
 
I have a 300XL in my RV-7A, with an AK950L annunciator panel. Did it myself :eek: You do need the annunciator panel, and a CDI (I use my GRT Sport) for a complete installation. The installation wiring is very different if you use an actual CDI instrument.
Since the 300XL is not WAAS, you also need another type of nav radio (VOR) to be legal IFR. I have an SL-30 for that role.
I don't believe an avionics shop 'certifies' an installation, they install the equipment per the appropriate specs and verify it works. You must do the same.
 
Thanks

I have a 300XL in my RV-7A, with an AK950L annunciator panel. Did it myself :eek: You do need the annunciator panel, and a CDI (I use my GRT Sport) for a complete installation. The installation wiring is very different if you use an actual CDI instrument.
Since the 300XL is not WAAS, you also need another type of nav radio (VOR) to be legal IFR. I have an SL-30 for that role.
I don't believe an avionics shop 'certifies' an installation, they install the equipment per the appropriate specs and verify it works. You must do the same.

Thanks for that...although, I am not sure I understand the point about VOR being needed. FAA requirements are for equipment necessary for navigation for the intended flight. WAAS, as I understand it is not necessary for enroute or for approach if a GPS approach is shown, not LPV approaches of course.
Ed
 
Thanks for that...although, I am not sure I understand the point about VOR being needed. FAA requirements are for equipment necessary for navigation for the intended flight. WAAS, as I understand it is not necessary for enroute or for approach if a GPS approach is shown, not LPV approaches of course.
Ed

The devil is in the details. The FAR's say "approved" gps may be used for IFR. FAR 1.1 (definitions) say a TSO is one way, but not necessarily the only way, to have an "approved" gps for use under IFR. (However, to the best of my knowledge, the FAA has never approved a gps for IFR except via the TSO route). Now, your GPS was TSO'd under TSO 129a ( think). That TSO limits use of the GPS under IFR to situations where back up non-gps navigation is available. There is even a requirement that your airport of intended landing, or the alternate, be accessible to you with your non-gps on-board equipment. The practical result of all this is that you have to have at least a conventional nav receiver (and a VOR, LOC, or ILS approach available at either your destination, or the alternate (with the forecast wx minimums as needed for your equipment)). The newer WAAS gps units are approved under a different TSO (144/145, I think?) which does not have this back-up nav requirement.
 
This is why VOR is needed: (the 300XL is a TSO-C129 device)

AIM 1-1-17 2 (a) states:
Aircraft using un-augmented GPS (TSO-C129() or TSO-C196()) for navigation under IFR must be equipped with an alternate approved and operational means of navigation suitable for navigating the proposed route of flight. (Examples of alternate navigation equipment include VOR or DME/DME/IRU capability). Active monitoring of alternative navigation equipment is not required when RAIM is available for integrity monitoring. Active monitoring of an alternate means of navigation is required when the GPS RAIM capability is lost.

Non WAAS GPS navigators are going the way of the buggy whip, but for those of us who still use buggy whips, this requirement still applies…
I just got a new Garmin 355 to replace my 300XL, so one more buggy whip will bite the dust soon :cool:
 
Thanks Again

This is why VOR is needed: (the 300XL is a TSO-C129 device)

AIM 1-1-17 2 (a) states:
Aircraft using un-augmented GPS (TSO-C129() or TSO-C196()) for navigation under IFR must be equipped with an alternate approved and operational means of navigation suitable for navigating the proposed route of flight. (Examples of alternate navigation equipment include VOR or DME/DME/IRU capability). Active monitoring of alternative navigation equipment is not required when RAIM is available for integrity monitoring. Active monitoring of an alternate means of navigation is required when the GPS RAIM capability is lost.

Non WAAS GPS navigators are going the way of the buggy whip, but for those of us who still use buggy whips, this requirement still applies…
I just got a new Garmin 355 to replace my 300XL, so one more buggy whip will bite the dust soon :cool:

Thanks again for the obviously well researched information and explanation. It certainly helps me, and probably others.
Ed
 
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