Airborne_Again wrote:
All G1000 systems have this capability
All WAAS GPS units have to have it. It is part of the TSO.
I think this may be true for CAS flight enroute in the future as well.
Why would one need “W” for enroute?
The 430/530 non-WAAS have not enough capacity to store direct to waypoints.
That, however, is a separate issue. For example my KLN94 can hold max 20 waypoints, which is a hassle, but it doesn’t actually affect anything I want to do because one has plenty of time enroute to clean up the passed ones and make room for new ones (obviously while keeping the general route intact so the LFOB figure remains correctly computed).
There are some WPs you can use as part of a procedure, but can’t used as direct to waypoints.
Do you mean that if e.g. you have a WP # limit of 20 and you have 18 loaded, you can load a GPS/LNAV procedure containing 5 more? I am fairly sure this would not work on the KLN94.
I wonder if one day we will not come full circle with vastly improved accelerometer technology and end up with Inertial Navigation in a small (suitable for light aircraft) sized box accurate enough to allow vertical navigation…
Highly unlikely. The solid state accelerometer technology is about 100x short of what you would need for useful enroute nav.
More or less like what a Cirrus Perspective does when you lose the GPS signal en route, it goes into dead reckoning mode and interpolates your position from airspeed and headings for 15 minutes, displaying a yellow plane icon on the MFD. Only much more precise as to allow to finish an approach.
15 minutes is an awful long time. We discussed this here before, many times. I think the current perf is a drift of around 1 degree of heading per minute, which is useless for flying.
Big jets use fibre optic gyros. You can buy an uncertified box for about €20k which has a GPS antenna one end and outputs “GPS+INS” NMEA the other end, so you could have an uncertified INS for the 20k. One could drive a tablet from it, or if you wanted to be illegal but clever you could hack an IFR GPS to accept this data 
The KLN94 has an internal GPS module which AFAIK outputs NMEA so you could patch this data into that quite easily. But the KLN94 does not do LPV…
All WAAS GPS units have to have it. It is part of the TSO.
Dead reckoning yes but what are the inputs? The TSO does not require this to be done with inertial inputs. It does no more than a (very modern) satnav when you go into a tunnel.
what_next wrote:
On the list of French aerodromes above there are quite a few Ryanair destinations. I don’t think they will do themselves a favor by decomissioning ILS. And a place like Annecy with difficult terrain will get ridiculously high minima with a GPS only approach (even with LPV).
ILS DH Annecy 310
LPV DH Annecy 360
@Jason
Your C-510 has LPV, right?
I don’t worry about the big BizJets so much as about all the lower cost IFR SEPs. There’s many that have perfect equipment for ILS, a DME, and all – but which can only be upgraded to LPV with a lot of money …
The result will be that many fly LNAV non precision approaches only, because many do have an IFR GPS for that … and that would clearly be a step back in safety.
Neil wrote:
ILS DH Annecy 310
LPV DH Annecy 360
That difference is prob just because Europe still won’t allow LPV to 200ft in spite of it working well to ILS minima in the US. So there always seems to be a 50ft spread between ILS and LPV minima.
@Flyer59 I agree many smaller aircraft that could be upgraded won’t be due to cost. But the one reason airports will try to keep ILS open is as @what_next said – to keep jet revenues. SEPs don’t pay the bills – CJ4s do.
Guillaume wrote:
LPV-200
Yes I know, we already discussed it on here. But no one is yet using it to my knowledge.
The withdrawal of ILS approaches had been scheduled quite a long time ago xc-aviation.co.uk
what_next wrote:
I think it is complete madness to make the infrastructure of a whole continent dependent on a system that is owned by the military of a foreign state.
So true.
