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What proportion of GA IFR aircraft are equipped for LPV approaches?

In addition to the above, you have the additional (ahem, theoretical) protection from VFR circuit traffic if ATC cleared you for the approach…

Not any more since stupid European regulations have taken away our airspace “G” which used to surround this kind of airfield. They are now RMZs (radio mandatory zones) so theoretically everybody flying there should listen in and transmit their position, but there is no kind of traffic separation. Now your approach clearance will be something like “callsign, cleared for the RNAV/GPS approach runway 25, QNH 1015, leave 5000ft accoring to the procedure, radar service terminates when leaving controlled airspace” (wherever that may be) and from then on you will be surrounded by folks with their own guaranteed 1500m visibility.

Last Edited by what_next at 28 Jan 13:07
EDDS - Stuttgart

It probably also puts a new slant on when I asked, a while ago, whether there were any LPVs in Europe at airports which had Customs but didn’t have an ILS.

Yes. I just flew one an hour ago. EDMS Straubing. Admittedly only a 580ft DH.

I have to say it was a lot quicker than when I had to hold for Achim!

EGTK Oxford

Let me rephrase my Q slightly:

Any LPVs in Europe at airports which

  • do have Customs , and
  • don’t have an ILS, and
  • do have a GPS/LNAV+V glideslope

In the UK, a number of airports don’t have the +V encoded because Jepp would not do it if there was the LP approach (not used by light GA AIUI) or something like that. I read some months ago that new Garmin software would fix this issue. Also I wonder if the IFD540 has this issue too.

If you have +V and the LPV has the same DH/MDH, the LPV offers zero value.

Administrator
Shoreham EGKA, United Kingdom

To an extent I agree Peter if rewuired visibility is the same but with a much lower visibility limit. LPV wins.

+V not being available relates to LNAV/VNAV being in the database. There are no LPs in Europe to my knowledge. Given Straubing has LNAV/VNAV right now it would be LPV or the NPA LNAV.

Also I believe Straubing are also looking to lower the LPV minima as they too have HIALS and the LNAV/VNAV minima are 130ft lower.

Last Edited by JasonC at 28 Jan 17:10
EGTK Oxford

If you have +V and the LPV has the same DH/MDH, the LPV offers zero value.

I wouldn’t say that. The only LPV capable GPS (Garmin GNS540W) that I have flown with only shows the synthetic glideslope when an approved LPV approach is activated. With normal GPS approaches it leaves you with the distance/altitude table. So even if the minimum is not much lower, it is much safer and easier to fly. (Interestingly “my” Citation that is not LPV capable shows this synthetic glideslope for every non precision approach. Of course you are not allowed to look at it )

EDDS - Stuttgart

Administrator
Shoreham EGKA, United Kingdom

There is a difference between a LNAV+V and a LPV even if they have the same MDA/DA. With official vertical guidance such as with an LPV, there are no step downs once the GS is intercepted. On the US charts the GS intercept point is at the FAF. With advisory vertical guidance provided by WAAS, one must still obey the minimum charted step down altitudes as the advisory GS does not permit the pilot to fly below the step down minimums. The advisory GS will nominally clear the step down minimums on an ISO standard day by design, however the baro altimeter rules, not the advisory GS. On a warm day, the GS will be below the baro altitude minimums and the reverse on a colder than ISO temperature day. On a warm day, this results in the pilot having to abandon the GS to not bust the stepdown minimum. In the US, there is no criteria for an approach below the MDA using the advisory glidepath. With an LPV, the glidepath may be followed to the runway below the DA and be assured of not encountering an obstacle assuming one has the runway in sight and stays on the final approach course center line.

There are distinct disadvantages to flying a constant angle descent path on an approach that was not designed for it. I authored an article in IFR magazine pointing them out. A vertically guided approach requires greater visibility to complete the approach than the dive and drive to the same MDA. Turbine aircraft with there greater energy and mass and slower spool up are much safer using a constant angle descent approach, but the same is not necessarily true for small piston GA aircraft. At least in the US, we fly approaches into fields that do not have approach lights, have shorter runways, more challenging obstacle environments, and no control tower. To complete an approach where the conditions are close to minimums for the ceiling under these conditions requires time to locate the runway and then decide if it is safe to land, An approach that descends to a minimum and requires a near instant decision is going to result in insufficient time to acquire the runway without lights unless the runway can be easily seen from the decision point. Flying along at the MDA buys the pilot what he needs to safely complete the approach, time.

KUZA, United States

There are distinct disadvantages to flying a constant angle descent path on an approach that was not designed for it.

In Europe, unless otherwise specified on the chart, every non-precision approach is designed and supposed to be flown as SCDA (stabilised constant descent angle) approach. This was introduced with JAR OPS more than ten years ago (OPS 1.430, don’t know the corresponding EASA OPS number). We stopped training and instructing step down approaches around that time. Jeppesen charts for European non-precision approaches were all redrawn with SCDA final approaches since then. There may be some exceptions, but I haven’t come across any of them lately.

EDDS - Stuttgart

@what next:

In Europe, unless otherwise specified on the chart, every non-precision approach is designed and supposed to be flown as SCDA (stabilised constant descent angle) approach. This was introduced with JAR OPS more than ten years ago (OPS 1.430, don’t know the corresponding EASA OPS number). We stopped training and instructing step down approaches around that time.

I can add that last year my US instructors were stressing the concept of SCDA and telling me that dive and drive is no longer being done. But then LPVs appear to be available in the US everywhere by now.

@NCYankee:

An approach that descends to a minimum and requires a near instant decision is going to result in insufficient time to acquire the runway without lights unless the runway can be easily seen from the decision point.

That appears to be a good point. But then I wonder how that is affected by even more technology that we have available now. If you combine an RNAV LPV approach with synthetic vision on the PFD in your technically advanced aircraft (TAA), then that might change – doesn’t it? Obviously all data that is being used for charts of any kind has to be correct and current. For synthetic vision that means you want to have current terrain and obstacle data so that you can “see” the runway from far away through the clouds. The final decision is then only about continue or going missed at the DA. That is then not different from a classic ILS approach.

[quoted text fixed – a quoted paragraph needs to be a paragraph i.e. have a blank line before/after it]

Frequent travels around Europe

To complete an approach where the conditions are close to minimums for the ceiling under these conditions requires time to locate the runway and then decide if it is safe to land, An approach that descends to a minimum and requires a near instant decision is going to result in insufficient time to acquire the runway without lights unless the runway can be easily seen from the decision point. Flying along at the MDA buys the pilot what he needs to safely complete the approach, time.

It is true you will need better visibility for a CDFA procedure compared to a “dive and drive” approach. OTOH I find CDFA so much easier to fly that for me it is worth it. In fact when I first did a CDFA it was like a revelation — I asked myself why NPAs haven’t been done like that all the time?

ESKC (Uppsala/Sundbro), Sweden
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