GPS175 LPV and GRT Mini GA flight director?

[BobTurner]

Bob, out of curiosity, how would one have done an IFR checkride back in the days prior to GPS, say the late 70's in a late 50's - mid 70's C152 equipped like the one at the flight school ? Perhaps the approach procedure was different then than now ?

In 1984 (still pre-GPS) my IFR check ride was an ILS, a VOR, and an NDB approach. My examiner loved NDB approaches. In fact, soon after take off, he asked me to use the ADF to navigate to an airport 40 nm away. When I got my CFII, 6 years later, I found out why. If you watched a pilot navigating with an ADF, you very quickly figured out if this guy "got it", or didn't. (ADF/NDB navigation required the pilot to figure out wind correction angles, appropriate corrections, reverse sensing, etc. A good ADF pilot could figure it all out in his head.). By the 1970's all the "direction finders" were "automatic" (the A in ADF) meaning an electric motor hooked up to the receiver was used to (electronically) rotate the antenna. Earlier radios (just DF, direction finders) the pilot had to rotate a crank (!) to rotate the antenna! ADFs were basically just AM radios (most could even bring in the AM radio stations, so you could listen to a ball game, or track to the local AM station at the destination. Shoot, we had an AM station that was right on the edge of SFO class B airspace (different name back then) and the ADF was very useful to make sure I didn't stray in where I didn't belong.) And they were very inexpensive, so almost all general aviation planes (except maybe 152 trainers) had one. They were terrible radios for actual IMC (if there was nearby lightning, they tended to point to it. In the rental plane I used, the examiner noted that the needle moved about 10 deg when he switched off the alternator! I peaked out from under the hood at him, and he just said, "You know, in the old days, that's all they had!"). NDB approaches were the very definition of "non-precision"!! GPS is light years ahead in accuracy, but, unfortunately, also light years ahead in cost (for this, I blame the FAA for letting their engineers go wild with the TSO requirements. I've seen one estimate that Garmin paid well over a million dollars in engineering costs to get their first TSO 129 on their pre-WAAS G430. And even then, the first two pages of the installation manual were full of leagalese about TSO tests they couldn't figure out how to do, and the alternative tests the FAA had allowed them to substitute, etc. BTW, did you know that GRT has an available option to display GPS approaches on some of its EFIS options? I think it's about $2K, plus their $500 GPS receiver designed for ADSB use. Unfortunately it is not TSO'd, and so is not legal to use under IFR. At least not yet.

 

[CF86301]

Okay, just for kicks, last night I emailed Jeff at GRT and asked the question about the GRT MINI **GA** and ARINC and approaches.

At 12:02 AM (this morning right after midnight), I got the following reply.
This from the guy that wrote the software.

~~~~~~~~~
Yes, the Mini-GA has the same capability as a Mini-AP for approach
display and autopilot functions including glideslope capture. It can do
ARINC-429 input and output with a GRT ARINC-429 module connected to one
of the 2 serial ports

~~~~~~~~~~

I hope that this helps.

This was implied by the message from Jeff at GRT in posts 24 and 28 above. Thanks for following up and confirming. The next question would be does the Mini GA firmware need to be updated to work properly with the ARINC 429 box.

 

[jclark]

This was implied by the message from Jeff at GRT in posts 24 and 28 above. Thanks for following up and confirming. The next question would be does the Mini GA firmware need to be updated to work properly with the ARINC 429 box.

I **think** that he stated clearly here that it works already.

The software should be updated if it is behind in any case. I would do that regardless.

 

[jackking123]

Bob, out of curiosity, how would one have done an IFR checkride back in the days prior to GPS, say the late 70's in a late 50's - m

Still needed 3 approaches in olden days.
One precision approach: ILS or PAR. (Precision Approach Radar)
Two non Precision approaches, pick one: NDB, VOR, LOC or ASR. (Airport Surveillance Radar)

There were a ton more NDB and VOR approaches back in the day. VOR approaches, although less of them today than in the past, are still here to stay for MON. FAA's VOR Minimum Operational Network (MON) ensures in lower 48 you can navigate safely during a GPS outage. Victor and Jet Airways and VOR approaches will be available for decades to come. Even as they shut down more VOR's they increase the service volume of others, including the DME range. The farthest distance between airports with a designated MON VOR or ILS instrument approach is typically 100 nautical miles (NM). So if you have VOR/LOC you can land every 100NM. It might not be where you want to go however. For normal operational efficiency one must have RNAV approach capability. Those are everywhere.

All NDB approaches are gone or almost gone, may be some in Alaska, and may be California? There were 2000 NDB's in the USA, with peak in the 70's and 80's. Every ILS had a LOM (Locator Outer Marker). The locator part was an NDB. ILS FAF or OM no longer use a NDB or Fan Marker, to ID the fix, they use DME or Radar. Of course the GPS (IFR capable) is a substitute for DME.

NDB - Non directional bacon, all but gone. NDB, like tail draggers, only real pilots can fly. Ha ha. They worked fine but had to do some mental gymnastics, have technique, could be a challenge to fly well with wind and just not as accurate, thus higher Mins. I flew freight into an airport with only an NDB approach one dark and stormy night. Terrain and obstacles all over and it was IMC. Normally no big deal, but there was convective activity (lighting) in the area. It played havoc with the NDB. I had to read the RMI between lighting interference swinging the needle. So I kind of miss NDB approaches, but never want to fly one for real in IMC ever again.

Bottom line in 2026 you need IFR capable GPS Navigator to file and fly IFR. I only have GPS in my RV. There is no mandatory requirement to having a VOR, unless it was needed to accomplish the flight. Obviously I am going to plan, file and fly RNAV missions. That is not very limiting now. In fact RNAV is often all you can get, at least to smaller airports. BUT like I mention FAA's MON, when GPS goes out (unlikely but it could). Alternatives is I am VFR I just land. You say it is IMC down to Mins. Another scenario I get talked down by ATC to get area of VFR or fly the nearest ASR approach (again talked down by COM). Last option take out my old trusty VHF transceiver from flight bag with VOR/LOC!