One can get the IFR data easily (airways, navaids, airports) but not airspace which – in Europe – is published only via the AIP PDFs. So that debate would be the same one as doing yet another tablet flight planning app… a lot of work.
That airspace work is already done where there are glider pilots. Depending of teh country it is provided by the NAA, the national aeroclub or some individuals. See here for a large collection. As it comes mainly from personal best effort, it comes with a large disclaimer.
Peter wrote:
I wonder how many homebuilts (Lyco engined) have a fuel totaliser?
Most of them in which you’d take a trip. Link
The EI units are inexpensive (US $558 with GPS input and flow transducer) and are used in homebuilts a lot, as well as being TSO’d and STC’d for certified aircraft on EI’s AML. Mine is consistently 2% conservative as installed and has been reliable. I need to adjust the calibration to take out the 2% error but it appears to be a good quality device.
Is the Landing FOB shown on the GPS or on the totaliser?
There is no TSO requirements for radios in non certified/experimental aircraft. Maybe some authorities (other than aviation also) demand that the radio is to be tested/approved, but that is a different thing.
Yes – that’s what I said, I think 
The end result is similar, however.
Peter wrote:
I wonder how many homebuilts (Lyco engined) have a fuel totaliser?
I would think most with EFIS/EMS. It’s a standard setup for all EFIS/EMS. Of the two microlights I fly, one has a separate fuel system from MGL, the other has it included in the Dynon. With the MGL fuel totalizer (the separate one), you can also include GPS signals to get actual range.
Peter wrote:
You cannot make anything that radiates anything (of aviation relevance) that is not approved.
Yes you can. There is no TSO requirements for radios in non certified/experimental aircraft. Maybe some authorities (other than aviation also) demand that the radio is to be tested/approved, but that is a different thing.
Peter wrote:
But, your Ipad is not displaying a CDI for flying approaches, or driving an autopilot
Who knows, in a homebuilt or microlight it could very well do that. Jeppesen has no way of knowing what I am using their data for, and yet they happily collect my money (no: my employers money!) for them …
Why is this different from the certified / STCd system?
For a system like that a manufacturer will be able to get some kind of liability insurance cover at a price which does not ruin his whole financial plan.
They license it to my iPad which is certainly not a certified GPS
But, your Ipad is not displaying a CDI for flying approaches, or driving an autopilot
The problem with a GNS clone will be that the yearly navdata upadate fee will be higher than the purchase cost of the unit itself which is not something users will like.
Agreed.
Regarding fuel computers: That would be an interesting field where a lot could be done. But personally I would be afraid of the legal implications that come with tinkering around the fuel system. If one of your selfmade transducers ever leaks or blocks the fuel flow, every lawyer in the United States will come after you. Even 50 years from now.
Why is this different from the certified / STCd system? The mechanicals would be identical. The Floscan transducer will not block the fuel flow even if the turbine jams.
I would think somebody who can build an RV or a Lancair to a reasonable standard can install those two hoses. After all the engine is a standard Lyco engine so the existing STC can just be followed as-is. I know there are flakey homebuilds but if somebody can’t tighten up two hoses right, they won’t be able to get the engine started… The airframe is not affected.
I wonder how many homebuilts (Lyco engined) have a fuel totaliser?
Peter wrote:
Jeppesen own all that stuff currently and it seems pretty clear that they would refuse to license it to any non-certified GPS.
They license it to my iPad which is certainly not a certified GPS 
The problem with a GNS clone will be that the yearly navdata upadate fee will be higher than the purchase cost of the unit itself which is not something users will like.
Regarding fuel computers: That would be an interesting field where a lot could be done. But personally I would be afraid of the legal implications that come with tinkering around the fuel system. If one of your selfmade transducers ever leaks or blocks the fuel flow, every lawyer in the United States will come after you. Even 50 years from now.
It may be doable but is it worth doing? I think most people that want to do serious GPS approaches in IMC in experimental aircraft will probably go with the existing certified systems that integrate seamlessly with their current PFD’s. Unless of course the non-certified one had the same functionality and was sold at a much lower price, which I doubt is possible because it would likely take fairly deep pockets to develop such a unit to the required standard that was able to interface with the existing PFD’s on the market.
On the other hand, there may be a market for a small lightweight nav radio designed to fit a 21/4" instrument cut-out, like many of the small com radios on the market. If these units could integrate with any CDI, HSI or glass PFD via an ARINC 429 interface, they could provide a back-up or low cost ILS capability for many aircraft.
