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I’m inheriting an IFR capable 1964 Cherokee 235 that is not equipped with a GPS. I’m looking at installing a Lynx NGT-9000 to get ADS-B compliant and gain the traffic and weather information.

Is there any way to leverage its integrated GPS/WAAS to enable LP/LPV approaches and file IFR direct? I don’t want to over panel this plane.

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    $\begingroup$ I feel this pain after I just dropped a substantial amount of cash Garminizing a 1965 Cherokee 180 just so I could fly GPS approaches. ADS-B Out is cheap, but a GPS I can use as a pilot is still hideously expensive :( $\endgroup$
    – voretaq7
    Mar 9, 2017 at 20:53

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Sorry, but windmills approach certified GPS systems do not work that way: A GPS approved for IFR navigation and approaches, like a Garmin 430W or GTN650 or an Avidyne IFD440, are more than just an approved position source such as what's included in the NGT-9000 transponder. They have an approved navigation database and interface with (or provide the equivalent of) a Course Deviation Indicator (CDI).

You can't just suck position data out of the NGT-9000 and fly around using it because while that device has an approved high-quality position source it doesn't have an IFR-approved navigation database, so there's no way to take that GPS data (your position as a point in space) and relate it to known waypoints (VORs, NDBs, airports, intersections, etc.) in a way the FAA considers satisfactory as a primary means of navigation.

You can take the GPS data from it and interface it with an iPad - Foreflight speaks the Lynx L3 language - to use for enhanced situational awareness, which is a huge win, but that's not enough to get you to file GPS flight plans: You would be limited to filing flight plans based on your other installed primary navigation instruments (VOR, ADF, DME).

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  • $\begingroup$ Why isn't there a gadget that can "overlay" an ADS-B position source and provide GPS navigation using that? $\endgroup$ Mar 10, 2017 at 3:37
  • $\begingroup$ @UnrecognizedFallingObject Mainly because as far as I'm aware nobody has built and certified one yet, and they'd have to get it approved to interface with each ADS-B position source (assuming they expose the position and integrity data over a hard-wired interface). At that point you're basically building a GTN625 (GPS navigator only) equivalent but with the GPS module external - Garmin retails those for only \$2000 less than the full GTN650 (GPS/Nav/Com) and maybe cut another \$2k out for the GPS, but you lose a lot of functionality so I'm not sure there'd be a huge market for them. $\endgroup$
    – voretaq7
    Mar 10, 2017 at 3:44

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