PilotEdge Forums

Hey all, just been looking at ( and flying ) the two different RNAV 27 approaches at KSAN, and want to make sure I'm getting this right! It looks to me that the only approach which has vertical guidance is the RNAV Z 27? The RNAV Y is lateral only, is that correct? If you had a GTN 750 I assume you could fly either of these depending on if you could get clearance?

Hmmmm.

It looks like only the RNAV Ry 9 has LPV (vertical guidance) mins.

Then again I can't remember what just LP stands for in the RNAV Ry 27.

And RNP... that's a question for someone else hehe.

According to Garmin, the GTN 750 meets the equipment performance to conduct RNP terminal departure and arrival procedures, and RNP approach procedures without RF (radius to fix) legs. Obviously a lot of the Zulu approaches, like the RNAV Z RWY27 at KSAN have RF legs, so the 750 doesn't meet the equipment requirement. And of course, in the RW Part 91 subpart K, 121, 125, 129, and 135 operators require operational approval from the FAA in addition to the equipment requirements. So for those of us not in the SAAAR category (Special Aircrew and Aircraft Authorization Required), if lower minima and vertical guidance are needed at KSAN we've got to use the runway 9 approaches - ILS or LPV.

The GTN 750 is WAAS. so it can fly the RNAV Y to the LP minimum. LP is Localizer Performance, so it has the same minimum as the LOC 27 approach even though it is using GPS. But as you said, no glidepath with that one.

Good to know.Thanks

I should clarify, the 750 should meet the equipment requirement for the Zulu 27 if approached from the LYNDI IAF, just not the KLOMN fix, which requires RF.

Similarly, the Zulu 24 at KCRQ has two IAFs: OCN and TANNR that require RF, but also has three non-RF IAFs: ZASOG, JLI, and ICUGA that should work with the 750, assuming its in the database.

Again, in the RW you'd still need crew authorization as part of a RNP AR (Authorization Required) approach, in addition to the equipment requirement. I find it hard to see the advantage of RNP outside of extreme terrain, especially when LPV approaches typically have lower minima, like the RNAV Y 24 at KCRQ, which is almost 300 ft lower than the Zulu 24 approach. Or even looking at the 27 approaches into KSAN; the RNP is only 80 feet lower than the LP and LOC approaches. Big deal.

From what I've read, Garmin is pushing the FAA for non-AR RF approaches, and I think the latest update to the 750 can fly them in a properly equipped aircraft. The RNAV X 24 at KCRQ is a non-AR RF approach.

The RW 750/650 received an upgrade in 2015 to allow them to fly RNP approaches with RF. Not sure if this applies to the sim version.

EDIT: should have read rtataryn's post more carefully. He says the same thing...

Actually Andrew, I didn't realize the GTNs were now approved for RNP RF's. I thought it was only for RF legs for the non-RNP approaches. But, yes, it looks like they are now as of March 2016 - at least to RNP 1.0. http://garmin.blogs.com/aviationalerts/ ... a-35c.html

Ils approaches are looking really attractive again !