NON-WAAS question

[CFIDave]

For what it's worth, the DA62 G1000 NXi is not certified for flying RNP AR approaches, although when installed in the King Air the NXi is RNP AR certified, and is capable of flying RF (Radius-to-Fix) legs. I'm guessing that is because the King Air's G1000 NXi installation includes Baro-VNAV, dual transponders, and dual ADAHRS.

US RNP approaches are clearly identified as "RNAV (RNP), and also specify special aircrew approval "AUTHORIZATION REQUIRED."

[linzhiming]

How can I recognise on an approach plate whether it is an RNP AR one? Just by seeing a RF depicted? Or is there a code/name?

For Jeppesen, the standard RNAV approaches (LNAV, LNAV/VNAV, LPV) are titled "RNAV (GPS)" whilst the RNP AR approaches are titled "RNAV (RNP)". Also the first line of comments would normally say in bold "Authorisation required." ICAO also seems to require that the AR (authorisation required) portion is always made prominent either via the "RNAV(RNP)" term or the explicit "(AR)" term (see page 7 of http://www.icao.int/MID/Documents/2016/ ... 20ICAO.pdf).

What I have seen in terms of published RNP AR approaches is that they normally exist only if a standard RNAV approach cannot be built, primarily because of terrain considerations that require very high precision and well-defined turns (RF turns). I am not sure how much spacing and traffic management considerations will become more important, but given that only a minority of RNAV systems currently supports RF/<RNP0.3 precision, I would think that the design preference would still be for an RNAV approach rather than an RNP AR approach.

That said, the fact that I can find some RNP AR approaches in Asia where no SBAS physically exists (no WAAS or EGNOS) highlights that WAAS receivers are apparently not really required for RNP AR approaches.

Need to think then before I spend 30k+ on a WAAS/EGNOS upgrade at this point in time..

In Europe, I think the main driver would be LPV vs LNAV minima only as the FAA enroute/alternate requirement (or WAAS benefit) does not exist as an equivalent requirement in Europe, at least for Part-NCC operations.

Wolfgang

[Colin]

I don't know how many are near the rest of you, but near me KPSP (Palm Springs) is the only one I can think of where it is the only option for getting in. (The Obamas tried to land after leaving the Whitehouse and wound up having to wait out some weather at nearby San Bernadino airport. Little planes could get in by getting under the clouds at Thermal and then heading over to PSP.)

[ememic99]

I have practical question related to this topic. When I load RNAV approach (non-WAAS G1000) the distances shown in FPL inset window are relative to previous point. So the last distance shown is between last point before MAP and MAP. However, on Jepp plates distances used for vertical guidance are relative to runway treshold. The question is how to relate distances written on plates to distances shown in FPL? I.e. I'm looking for the same feature as when using DME in LOC/DME or VOR/DME approaches.

[CFIDave]

On the MFD, when you display your flight plan with approach waypoints, you can easily switch from individual leg distances to distance to the runway. Just select the CUM (Cumulative) softkey.

[ememic99]

On the MFD, when you display your flight plan with approach waypoints, you can easily switch from individual leg distances to distance to the runway. Just select the CUM (Cumulative) softkey.

The first problem is that the runway threshold is not loaded as point in FPL. You can add airport manually but such entry will point to mid of runway rather than to threshold. How to get runway threshold in FPL?

The second issue is if I select CUM at MFD, will this change presentation at inset FPL window on PFD?

[CFIDave]

You typically see MAP waypoint that's pretty close to runway threshold. Otherwise, it's very easy to take CUM mileage distance to center of runway and subtract .5 mile for a 5000 foot runway, etc. Very easy...

I don't recall that MFD FPL map setting will affect little PFD inset map.

[ememic99]

MAP is MAP and doesn't necessary have to be close to RW threshold. And calculating anything while in IMC approaching minimum is not easy task.

[Aart]

Maybe in the cases where the MAP does not coincide with the runway you could make a user waypoint at the RW threshold. While you are still en-route of course

[CFIDave]

MAP is MAP and doesn't necessary have to be close to RW threshold. And calculating anything while in IMC approaching minimum is not easy task.

The CUM distance to the middle of the airport runway requires no calculation. Unless you're landing on a 10,000 foot runway, it's only going to be off by about 1/2 mile from runway threshold distance. How hard is that to calculate? I don't need more than that level of precision when navigating, or making position reports to ATC or on CTAF.