Six years ago here, various discussions about CAT 3, but nothing has happened
Possibly with GBAS but am guessing the loss of integrity for the last 800 m is a technical problem?
Technically, it’s possible with GBAS unlikely with SBAS as the specs have been set already for wide area although one can easily show it’s fine for 50ft DH
Economically, Cat3 operation runway would costs a lot of extras (ATC, RFFS, radar, lights, ancillary equipment,) that would kill any cost benefit from having RNP(50ft) as alternative to ILS(50ft)
RobertL18C wrote:
Possibly with GBAS but am guessing the loss of integrity for the last 800 m is a technical problem?
+1
I’ve seen reports for GLS trials down to CAT III on big planes and there is a lot of talk of the future of GLS in CAT II-III.
The other thing is US is well advanced on the topic but bizarrely they have not picked the idea of “LPV 50ft” for some reason? for GNSS applications, there are way more savvy in US across FAA, US operators and pilots: the LPV was norm in US since 2005 and LNAV was norm in Alaska since 1999 and there was lot of “technical need & expertise” in those corners, in the other hand, while I have seen few Airbus/EGNOS presentations on GBAS for “RNP CAT3”, I will not hold my breath….not sure how Pilot/Operator/Aircraft will get “RNP CAT3”? I mean for the average sunshine operator, average B737 and average ATPL captain, It took them 15 years to learn RNP LPV200 fro Cat1…
This may seem a bit of personal judgement based on limited interactions but the most skeptical people I come across on GNSS tend to be those in working in “airline industry”?? I am sure it’s proportional to the amount of understanding how these things work, or the amount of how much they use it, or personal experience of failures after 20kh: lot will tell you they don’t trust LPV to Hethrow bellow 50ft (the GPS jamming vehicle has to be on the runway) as the last time they overflew Turkey they had some jamming at 40,000ft (the GPS jamming vehicle is in some war zone 250m away)
The Garmin Emergency Autoland System does CAT III based on LPV – so technically it’s not impossible. (Obviously for non emergency situations it take a lot more reliability…)
I’d assume the challenges are more economical ones: Cat 2/3 operations are very special and costly in terms of equipment, training, currency, etc. Changing that system is extremely costly and the benefit is limited to saving some maintenance cost on (existing) ILS equipment.
I didn’t mean for GA. That will “never” happen, because CAT3 needs an auto throttle which is “impossible” to certify, for a piston aircraft.
I meant for airlines, and they already have the right runway, ATC, etc.
LPV can already be “flown” by GA all the way to the tarmac, if your autopilot can cope with low speed handling.
Tried flying a GPS approach a few years ago with a GTN 750 down to 50ft in VMC and with instructor in the right seat and ATC ok. It worked like a charm.
Ibra wrote:
I mean for the average sunshine operator, average B737 and average ATPL captain, It took them 15 years to learn RNP LPV200 fro Cat1…
The airlines with very few exceptions have not equipped with WAAS systems, so almost no experience at all with LPV. For all practical purposes, only GA has adopted LPV capability. Some air carrier aircraft are equipped for GLS, but there are only two airports in the US that have GLS approaches, KIAH and KEWR and they are currently only supporting Cat 1.
