I’ve been looking at the approach minima for a couple of GA airfields that have GNSS approaches and it would appear that they offer little benefit in terms of minima compared to NDB. However LPV approaches should offer minima similar to that of an ILS.
Now initially I suspected that at some airfields this won’t matter as a lot of their usage is for flight training purposes eg Shoreham. However I then got thinking a little more and wondered if such equipment would actually expand the commercial viability of such airfields as the lower minim would make them practical destinations for the citation, king air mob and lets face it a couple of them a day would give a far bigger income than 40 jodels.
LPV approaches are great. Agreed a basic non precision GPS approach doesn’t add much more than accuracy over a VOR/DME.
Did LPV into Calais last week. Right down to 200ft and easy with a GPS autopilot ie no CDI mode changes.
Much cheaper than an ILS to install.
they offer little benefit in terms of minima compared to NDB.
Yes – very little improvement at Shoreham. 860ft v 800ft on 20, 480ft to 430ft on 02.
However LPV approaches should offer minima similar to that of an ILS.
They will but not necessarily to 200ft AAL. Lydd EGMD for example is 418ft AAL (430ft QNH) – possibly due to the power station.
a couple of them a day would give a far bigger income than 40 jodels.
I couldn’t agree more – especially as the IFR traffic is going to be using the IAP during slack periods.
Being based at Shoreham I find that 50% of my cancellations are due to the likelihood of not being able to get back home.
If they could get LPV with an MDH of 500ft or less that would probably convince me to blow away the five figures on the upgrade to fly it. Yesterday I measured the available stack height and it is 6" (KLN94+KMD550) which would be OK for something like a GTN750 (6" high) or a KSN770 (5.25" high). The big problem is that I don’t know of a UK avionics shop I would trust to install it – following my TCAS experience at one of the biggest ones.
I think the flying schools that do IFR training at the non-ILS airports must by now have reasonable planes e.g. G1000 and thus LPV capable, and could use the LPV for the precision approach training. The schools I know who operate the most shagged hardware are all based at ILS airports, which is understandable.
Much cheaper than an ILS to install
I think the installation cost is 100% courtesy of the US taxpayer 
There is a survey, which reportedly costs of the order of 10k-30k, and a test flight for which I am sure the CAA approved company charges a good few bob. I don’t know if there is a regular test flight requirement as there is with an ILS.
WAAS does not work here – so its EGNOS and the European taxpayer enabling LPV approaches
They would be great if they could be implemented easier and in more places.
Actually, this technology for the first time realistically opens possibilities for precision approaches to minor airfields. This could, if it is not hampered in it’s development by the powers that are, be a major safety improvement as well as, as Peter sais, a major convenience and value increase as well as a motivation to get the IR for folks who never go to larger airports.
The problem is, as usual, that the day you start talking of making an airport IFR, all sorts of misantropic groups come out of the woodwork and announce their fierce opposition. We had such a discussion here not too long ago, when a grass airfield wanted to finally install a concrete runway as a safety factor. The anti noise groups around that airfield soon sucked up all the money put aside for this purpose fighting the opposition lawyers until they had to give up. That is the situation which lots of airfields who could profit from this technology find themselves in. For the anti noise groups, a safety increase is bad news, because, as one of their exponents put it, “only a dead pilot is a good pilot”.
What would be needed is a more strict and straightforward infrastructure legislation which stops every rabbit breeding club from becoming a no-go factor for the development for airports, roads and other transport infrastructure. Especcially safety enhancements should be exempted from the legal hurdles these people put up, knowing that they are not in their right but that their cashbox is bigger.
Best regards
Urs
WAAS does not work here – so its EGNOS and the European taxpayer enabling LPV approaches
The “enabling” is technically true but the US taxpayer is still providing the main system.
Actually the history of EGNOS is a bit of a joke. At one stage it was going to be tied to the “will create 100000 jobs” Galileo white elephant but they gave up on it later.
all sorts of misantropic groups come out of the woodwork and announce their fierce opposition
It is indeed very hard to convert a grass runway to a hard runway, in terms of getting what in the UK is called the planning permision.
A number of airfields have tried it and I think most of them have failed – the local politics don’t like the presumed increase in traffic. I think LPV will be of most use to existing hard runways.
Also the runway needs to be long enough. The UK CAA claims to be looking at relaxing some of the requirement but I don’t ever see LPV approaches to say 700m runways.
Plus there will be objections from airports which already meet the requirements at some substantial cost and which don’t want to lose business to others nearby.
So everything takes time
The biggest problem in the UK is the current requirement for full ATC for any IAP, so LPV is in any case currently relevant only to full ATC airports.
