Curved approach path

[flyingron]

RNAV (GPS) approaches can use the curved path RF leg type, but you won't find any of these in the existing WAAS GPS databases as none of the Garmin panel mount GPS units support the RF leg in their AFMS.

Well, the "real" Garmin units (including the GTNs) don't. The GNS 480 that came out of the old Apollo/UPSAT group in Salem has always supported all the ARINC leg types.

I don't however know if Jepp coded any of the subject approaches into the 480 database or not. I guess I can look Friday when I get to the aircraft.

 

[John Collins]

Well, the "real" Garmin units (including the GTNs) don't. The GNS 480 that came out of the old Apollo/UPSAT group in Salem has always supported all the ARINC leg types.

I don't however know if Jepp coded any of the subject approaches into the 480 database or not. I guess I can look Friday when I get to the aircraft.

Actually, as I understand it, all the Garmin WAAS GPS have the capability to fly the RF leg types, but that it will require a software update to unlock the capability. In the mean time, no approach with the RF leg type is included in the database. There is one Garmin exception, a recent version of the G1000 for the King Air added the capability.

 

[John Collins]

Although I can easily come to the same conclusion that because the DME is used for the lateral course guidance on the MTN 15 VOR/DME, it can't be flown using the GPS to substitute for the DME, I have not been able to get the FAA to confirm this. This procedure is not in the database because there isn't an ARINC coding for it, at least that is what Jeppesen claimed when I asked why. This is a one of a kind approach in the US. A DME arc is a very crude lateral path with pilots expected to remain on the center DME value +/- 1 NM. The TERPS for the arc require a primary obstacle clearance +/- 4 NM around the center line with another 2 NM secondary. At the MAP, all this approach does is keep you in the same county as the airport.

 

[flyingron]

This is a one of a kind approach in the US. A DME arc is a very crude lateral path with pilots expected to remain on the center DME value +/- 1 NM. T

Actually, it's two of a kind. Wallops Island also has a similar approach.

 

[flyingron]

Actually, as I understand it, all the Garmin WAAS GPS have the capability to fly the RF leg types, but that it will require a software update to unlock the capability. In the mean time, no approach with the RF leg type is included in the database. There is one Garmin exception, a recent version of the G1000 for the King Air added the capability.

Again, to my knowledge, and the 480 pilot guide supports this, it has always supported RF legs. Whether Jepp codes these approaches in the database is another story but there's no "software update" or "unlocking" required.

 

[azure]

Again, to my knowledge, and the 480 pilot guide supports this, it has always supported RF legs. Whether Jepp codes these approaches in the database is another story but there's no "software update" or "unlocking" required.

Page reference? All I can find in the GNS480 Pilot's Guide is the standard DME "arc to a fix" leg type. I don't know the precision required for a RF leg but I assume it's greater than the standard +- 1nm John alluded to for a DME arc.