Why does this approach have higher LNAV/VNAV minimums than just LNAV?

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Rockie
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

valleyboy wrote:So all this banter and why not just do the LPV approach
Don't we all wish.... The problem is LPV requires WAAS which costs money. Money most (not all) airlines will not spend until they're forced to. Rare is the airline that sees the economic benefits and glaringly obvious safety aspect of LPV approaches. The FAA gets it though, hopefully followed by TC at some point.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

What are the detailed economic benefits to an airline of spending on LPV equipment? And the safety improvements are...?

How many approaches are missed or flights canceled due to inadequate approach minimums at revenue destinations that have LPV approaches? On how many of those occasions would LPV have saved the airline money?
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by lazyeight »

photofly wrote:What are the detailed economic benefits to an airline of spending on LPV equipment? And the safety improvements are...?

How many approaches are missed or flights canceled due to inadequate approach minimums at revenue destinations that have LPV approaches? On how many of those occasions would LPV have saved the airline money?
The benefits could be not going missed in an airport where the next lowest approach is a VOR/DME with minimums nearly 300 feet higher. Seen it happen personally multiple multiple times and lots of angry customers wondering why the little planes (LPV certified) are landing yet the "big" sked plane (were talking Metro here) which they are paying hundreds for a ticket on went missed for the 3rd time today. So to answer your question, a lot of money to be saved. In fuel costs, rescheduling etc. etc.
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photofly
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

Apparently the costs savings still aren't enough to justify the costs.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by lazyeight »

Well, said airline has been slowly upgrading their fleet. Most of the airplanes from my understanding are now equipped but not everyone is trained to fly them yet. GPS certification costs a lot of money for flight crews mid PPC cycle. My guess is within a year they will be all certified once everyone is through recurrent training.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

LPV's provide ILS like precision, many with 200 and a half limits, and can be produced for almost any airport anywhere without the need for an expensive ILS installation - cost savings airlines could insist on to reduce their fees paid to NavCanada, airports and other national service providers. The FAA is all over that. On Canada's east coast alone an LPV approach would often make the difference in getting in or not especially in the winter. Runway 25 in Ottawa anyone?

The safety enhancements are obvious as the weather degrades and when taken in context with stabilized approaches. They are unaffected by temperature and guarantee that the aircraft is tracking horizontally and vertically toward the correct touchdown spot on the runway upon reaching minimums. I'll take precision over non-precision any day.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by 55+ »

Rockie wrote:LPV's provide ILS like precision, many with 200 and a half limits, and can be produced for almost any airport anywhere without the need for an expensive ILS installation - cost savings airlines could insist on to reduce their fees paid to NavCanada, airports and other national service providers. The FAA is all over that. On Canada's east coast alone an LPV approach would often make the difference in getting in or not especially in the winter. Runway 25 in Ottawa anyone?

The safety enhancements are obvious as the weather degrades and when taken in context with stabilized approaches. They are unaffected by temperature and guarantee that the aircraft is tracking horizontally and vertically toward the correct touchdown spot on the runway upon reaching minimums. I'll take precision over non-precision any day.
Some clarification to the above. In order for Precision landing limits(200ft HAT), vis ½, (A)the airport itself has to be Certified in accordance to criteria in TP-312- Aerodrome Standards and Recommended Practices and (B) The landing surface aka Runway has to assessed as meeting Precision Criteria in regards to take off/approach sloped, strip widths, transitional slopes etc. If those criteria are not met the lowest landing minima approved is 250ft HAT
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

Rockie wrote:LPV's provide ILS like precision, many with 200 and a half limits, and can be produced for almost any airport anywhere without the need for an expensive ILS installation - cost savings airlines could insist on to reduce their fees paid to NavCanada, airports and other national service providers. The FAA is all over that. On Canada's east coast alone an LPV approach would often make the difference in getting in or not especially in the winter. Runway 25 in Ottawa anyone?

The safety enhancements are obvious as the weather degrades and when taken in context with stabilized approaches. They are unaffected by temperature and guarantee that the aircraft is tracking horizontally and vertically toward the correct touchdown spot on the runway upon reaching minimums. I'll take precision over non-precision any day.
A NavCanada manager responsible in this area told me the delays in the introduction of more LPV approaches are due to airport operators: an LPV approach needs a detailed site survey for obstacles and a commitment from the airport operator to fund the periodic re-surveys required (as they are for an ILS with similar minimums). Airport operators are not exactly falling over themselves to sign up for this new ongoing cost.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

photofly wrote:A NavCanada manager responsible in this area told me the delays in the introduction of more LPV approaches are due to airport operators: an LPV approach needs a detailed site survey for obstacles and a commitment from the airport operator to fund the periodic re-surveys required (as they are for an ILS with similar minimums). Airport operators are not exactly falling over themselves to sign up for this new ongoing cost.
Airport operators can be very short sighted (look at Ottawa), and so can airlines. A LPV gives ILS like capability without the need for an expensive ILS installation. No brainer...
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

If you present it as a choice between an LPV approach and an ILS then it's a no brainer, sure. But that's a false choice. Most airports are clearly happy having neither.

It may be true that a Ford Galaxy is cheaper or better value than a Ferrari, but that's irrelevant if you don't want to buy a car at all.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

photofly wrote:If you present it as a choice between an LPV approach and an ILS then it's a no brainer, sure. But that's a false choice. Most airports are clearly happy having neither.

It may be true that a Ford Galaxy is cheaper or better value than a Ferrari, but that's irrelevant if you don't want to buy a car at all.
Think of it this way, a community somewhere that relies on its airport but only has a crappy NDB approach has someone offer to install and maintain an ILS installation with 250 foot minimums to all its runways - for free. All the community has to do is get someone to build the approach for it.

Sure, the community might pass up such a deal but it would be foolish of them to do so.

Alternatively an airport has instrument runways but cannot justify the cost of purchasing and maintaining a CAT I ILS, or maybe they can but recognize there is a much cheaper option that provides the same capability.

Trying to find an argument here against LPV's but I just can't.
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Last edited by Rockie on Sat Aug 27, 2016 3:25 am, edited 1 time in total.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

An LPV approach is not free! They have to pay for annual surveys! For ever! Expensive ongoing costs to maintain the approach! Costs money! Every year! Not free! Cheaper than an ILS, but not free!
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

photofly wrote:An LPV approach is not free! They have to pay for annual surveys! For ever! Expensive! Cheaper than an ILS, but not free!
Yes it's free, the Americans are paying for it. And if the airport already has a crappy NDB approach they're already paying for surveys. Crappy NDB/VOR approach with a navaid that needs to be installed and maintained - or a precision LPV approach that doesn't? Hmmm, let's think about that for a second...,
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

What are you talking about? The Americans are going to pay for surveyors in fluorescent jackets with theodolites to troll out to Quaqtaq every year to confirm there are no new encroachments on the approach so that Administration Régionale Kativik can have an LPV approach at their airport? You're smoking some good stuff there!

The ongoing survey requirements for a precision or precision-like approach are much higher than anything required for an NDB or LNAV non-precision approach. Airports have been slow to sign up for those significant additional costs.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

photofly wrote:What are you talking about? The Americans are going to pay for surveyors in fluorescent jackets with theodolites to troll out to Quaqtaq every year to confirm there are no new encroachments on the approach so that Administration Régionale Kativik can have an LPV approach at their airport? You're smoking some good stuff there!
The Americans are paying 100% of the cost of the GPS and SBAS systems, and have guaranteed full time, no cost availability to all users. Look it up. The Europeans and Russians have done the same.

If the Administration Regionale Kativik is already paying to survey a crappy NDB approach doesn't a LPV make more sense? In fact they can have both since they're paying for the survey anyway right? Obstacle data is obstacle data - hills don't get higher just because there's another approach being built.

What's so hard to understand about this really?
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by AuxBatOn »

Antenna and structures are built. The approach needs to be re-surveyed every year at the operator's cost.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

Rockie wrote:
photofly wrote:What are you talking about? The Americans are going to pay for surveyors in fluorescent jackets with theodolites to troll out to Quaqtaq every year to confirm there are no new encroachments on the approach so that Administration Régionale Kativik can have an LPV approach at their airport? You're smoking some good stuff there!
The Americans are paying 100% of the cost of the GPS and SBAS systems, and have guaranteed full time, no cost availability to all users. Look it up. The Europeans and Russians have done the same.

If the Administration Regionale Kativik is already paying to survey a crappy NDB approach doesn't a LPV make more sense? In fact they can have both since they're paying for the survey anyway right? Obstacle data is obstacle data - hills don't get higher just because there's another approach being built.

What's so hard to understand about this really?
Apparently the bit that's difficult for you to understand is that as a plain fact, the ongoing survey costs of an LPV approach are much higher than the ongoing survey costs of LNAV, NDB approaches et al. And that airport operators are not rushing to commit to those extra costs.

You find it incomprehensible that airports aren't opening LPV approaches every fortnight. I give you the reason, as reported to me by the NavCanada manager responsible in Ontario for LPV approaches, that makes it entirely comprehensible. Frustrating, sure - but understandable.
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by complexintentions »

We still have the option to use LNAV only minimums instead of the LNAV/VNAV minimums and frequently do if weather isn't a deciding factor as there is a lot less work required for LNAV only approaches.
Could you please explain what you mean that "there is a lot less work required for LNAV only approaches"? Perhaps in the setup phase i.e. approach validation and the like, but surely flying an approach with vertical/horizontal guidance is a lot less work than doing it in basic modes?

Incidentally I've never done a LPV approach in my entire career, I confess I had to look into the term. I gather it's more of a Canada/US thing? Other than ILS, my own airline operations have always been LNAV/VNAV. (Pre-airline, different story! Chasing that NDB needle when the wind is howling, ugh, don't miss it.) Even for a VOR approach, if it's in the database, can be flown as an overlay with LNAV/VNAV guidance. (To MDA, of course). On very rare occasion if the approach won't validate the vertical might be flown in V/S or FPA, but in thousands of approaches that's happened maybe twice.

I agree with Rockie 100% that airports over a certain size that drag their heels on lower-minimum approaches are shortsighted and saving a dime to spend a dollar. And of course there's the safety issue, but as they like to say in Canadian aviation, "Safety Third!". I mean really, what's the odd 320 plunking in short of YHZ between friends?
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by Rockie »

In the US there are 1291 CAT I ILS's.

In the US as of last May there were 3678 LPV approaches, 940 of which have 200 foot minimums and 1739 of which are to non-ILS runways. More are being developed every month.

In the US there are a combined 1681 NDB/VOR approaches compared to 6073 LNAV approaches and 3553 LNAV/VNAV approaches.

The FAA clearly gets it.

Your airports, TC and too many operators in Canada might not get it yet Photofly, but sooner or later they will.

Also if you would please explain the cost difference in finding the highest obstacles in any given area. Does a 200 foot tower on final cost more to find for a LPV approach than it does for a NDB approach? Is the obstacle data not valid for both approaches? In the OP example the controlling obstacle for the LPV seems to be the same one for the circling. Did it cost more to find for the LPV?
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Re: Why does this approach have higher LNAV/VNAV minimums than just LNAV?

Post by photofly »

I think the FAA funds the costs of the LPV approach, much like they provide a lot of airport funding, out of tax dollars.

Canada doesn't have nearly the same level of federal investment in aviation. But if we did, those dollars aren't free - they come out of everyone's pocket. Most people would probably say that the people who would benefit from better approaches should pay, so that means higher airfares and more investment from airlines into airports. I think everyone "gets it" but nobody has an economic incentive to do anything about it.
Also if you would please explain the cost difference in finding the highest obstacles in any given area. Does a 200 foot tower on final cost more to find for a LPV approach than it does for a NDB approach? Is the obstacle data not valid for both approaches? In the OP example the controlling obstacle for the LPV seems to be the same one for the circling. Did it cost more to find for the LPV?
I can't answer that. I can only tell you what was told to me, which is that more or less any airport in Canada can have an LPV approach approved shortly after pressing the button on approving the ongoing survey costs. The lack of LPV approaches is entirely down to airport operators not providing the funding.
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