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LPV or ILS


Joe Larussa

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I too prefer the LPV because the signal is more stable and not prone to interference from ground traffic.  However, as gsengle said, the ILS sometimes has lower minimums.  For example, at Tacoma Narrows (TIW) the LPV 17 minimums are to 344' (400-5/8) while the ILS to 17 is good to 200' (200-1/2).

Practically speaking, probably not a big deal since the weather is rarely right at minimums (except for every approach in the simulator).

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21 minutes ago, gsengle said:

If a busy airport is using the ILS for all traffic have you requested the LPV? I find I only use it at smaller airports...

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Agreed.  There have been a couple times I asked for the RNAV and get an ILS instead at the bigger controlled airports.  Maybe because the old ATC fella knew it was a training flight and he wasn't paying attention?

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  • 3 weeks later...
On 4/14/2016 at 10:46 AM, Piloto said:

Where the LPV shines is when coupled to the autopilot. You can have the A/P coupled from take off to approach all the way to DH. All you have to do is adjust the throttle, set flaps and gear

José

Absolutely.

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We had a couple of LPV approaches at local airports disappear and revert to Lnav approaches.  I'm not sure why.  

Anyone else notice disappearing LPV's?

I wonder if there are new TERPs requirements or perhaps the airport not longer meets them. My airport is slated to be paved and widened to 60'. Our airport manager went through the FAA requirements for approaches. The amount of clear area between the LPV served runway and obstructions is pretty significant. Also, the minimum runway width for an LPV is 60'. Wonder if any of those factors play into it what you are seeing?

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2 hours ago, Marauder said:

Wonder if any of those factors play into it what you are seeing?

That's a possibility.  

The reversion caught me by surprise....significant minima differences!

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I too choose LPV whenever there is an option.  I just did that last Friday in fact in the soup, and the approach controller asked after the request if I wanted the ILS and I had to re-confirm the GPS approach.  I wonder if many of them don't realize that the LPV gets near-ILS minimums typically since all of the GPS approaches are charted the same.  I much prefer the fairly standard layouts so flying one is pretty much the same as flying another, whereas ILS can get you anything from arcs to procedure turns or vectors to intercept somewhere...

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What I have noticed is that ATC generally is going to require you to fly the whole approach with an LPV, but they are not at all reluctant to vector onto an ILS, in fact, they insist on it most of the time.  I will grant that the LPVs are typically at rual nontowered airports and ATC probably does not have the radar coverage they need for vectoring.  Most LPVs take quite a bit of time to fly, if no vectoring.  I take the ILS any time it is available, same amount of button pushing in my aircraft (KFC200 with GPSS).  I still have to push APCH, and sometime before the FAF.  Everything else is the same, the AP just uses a GPS waypoint and computed glidepath instead of a broadcast signaal.

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  • 1 month later...
On May 4, 2016 at 7:47 PM, jlunseth said:

What I have noticed is that ATC generally is going to require you to fly the whole approach with an LPV, but they are not at all reluctant to vector onto an ILS, in fact, they insist on it most of the time.  I will grant that the LPVs are typically at rual nontowered airports and ATC probably does not have the radar coverage they need for vectoring.  Most LPVs take quite a bit of time to fly, if no vectoring.  I take the ILS any time it is available.....

I've found ATC vectors me to the IF/IAF on LPV approaches in metro areas.  They only vector me to the outer IAF if it's on the way.  

In unmonitored approaches you get to fly the whole procedure.  There just aren't many unmonitored ILS.  

As almost all LPV approaches are "T" shaped you can pick the better located IAF of the two.  

If a major airport is using ILS for its inbound traffic I go with their flow.  After all most airliners can't fly LPV approaches and we don't want to flaunt our superior capability.  

With the GTN750 driving the KFC225 I do have to watch for the message "Enable Autopilot Outputs" before selecting APR mode during WAAS approaches.  

But once it's all coupled up the WAAS GPS signal guides the autopilot so well that if you never see the runway the debris field will be right down the centerline...

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I have been using the LPV approach into KGAI. As Jose mentioned, it is really cool to connect the autopilot after take off, engage the GPSS and then not to touch the controls (with the exception of gear, throttle and flaps) until DH... In a way it is even a bit scary to sit there and to just wait and control. But it works extremely well. 

The only issue that I noticed is that you really have to understand the rationale of your equipment. What the meaning of each function actually is and how it works. Otherwise you may run into the "why is he doing this"  syndrome... which may be dangerous for your health.

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4 hours ago, Oscar Avalle said:

I have been using the LPV approach into KGAI. As Jose mentioned, it is really cool to connect the autopilot after take off, engage the GPSS and then not to touch the controls (with the exception of gear, throttle and flaps) until DH... In a way it is even a bit scary to sit there and to just wait and control. But it works extremely well. 

The only issue that I noticed is that you have to really understand the rationale of your equipment. What the meaning of each function actually is and how it works. Otherwise you may run into the "why is he doing this"  syndrome... which may be dangerous for your health.

I think you have the STEC AP. Have you ever done the manual intercept angle? (pushing the HDG & NAV buttons at the same time) I have a video of it doing an 80 degree intercept.

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4 hours ago, Oscar Avalle said: I have been using the LPV approach into KGAI. As Jose mentioned, it is really cool to connect the autopilot after take off, engage the GPSS and then not to touch the controls (with the exception of gear, throttle and flaps) until DH... In a way it is even a bit scary to sit there and to just wait and control. But it works extremely well. 

The only issue that I noticed is that you have to really understand the rationale of your equipment. What the meaning of each function actually is and how it works. Otherwise you may run into the "why is he doing this"  syndrome... which may be dangerous for your health.

I think you have the STEC AP. Have you ever done the manual intercept angle? (pushing the HDG & NAV buttons at the same time) I have a video of it doing an 80 degree intercept.

Never heard of this, my manual specifically states must be with 10 degrees of heading and 1 needle width?

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3 hours ago, Hyett6420 said:

Is there a map like this for Europe?

Not on the FAA site, no.

https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/approaches/

EGNOS enabled LPV approaches in Europe can be seen in a map at

https://egnos-user-support.essp-sas.eu

 

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8 hours ago, teejayevans said:

Never heard of this, my manual specifically states must be with 10 degrees of heading and 1 needle width?

Here is the section of the manual that talks about the dual intercept:

Capture.JPG

At the end of this video you can see an example of an 80 degree intercept. It will fly through the final course a little, but certainly manageable.

 

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