Peter wrote:
SMS is more reliable than mobile data in many scenarios.
IME not if roaming is involved, which it will usually be in this case.
That depends on the quality of the network you are with. Vodafone costs more than many but they invest in infrastructure and the network works properly and in general (there are always geographical variations) better than any other. All over Europe, there are many poor quality but cheap networks which work well domestically and get their reputation that way.
Telegram (& WhatsApp) work fine on ground and sometimes while airborne, honestly, without internet, I am not flying at all, it’s just too much hassle, starting with sending fax PN to customs and getting the phone number for PPR, I don’t print these one week in advance 
Maybe AR SMS API makes more sense if one is using AutoRouter in southern Sudan or middle of Greenland?
Probably…
Actually SMS is delivered at much higher altitudes than you get mobile data at.
The real issue is that SMS is not “free” – you pay per message. For a free service, one should not expect that. The AR has server hosting costs too; hopefully they are covered by the Garmin Pilot licensing deal.
The AFTN (needed for V Z Y flight plans; only “I” FPs go wholly to Eurocontrol via their VPN) is not free either and actually much more expensive than SMS (last time I was involved). No idea what one does about that. There has to be a cross-subsidy from somewhere.
The real issue is that SMS is not “free” – you pay per message
Yes and the pilot pays way more in SMS than what AR pays to reply to him by SMS
Data only SIM cards are dirt cheap in comparaison
the pilot pays way more in SMS
I don’t understand.
Data only SIM cards are dirt cheap in comparaison
They cannot be used in a phone, unless you go 100% VOIP which is pretty difficult to do (I have done it; too tricky for incoming, and often poor quality outgoing calls).
They can be used in a tablet, if you do not need it as a phone backup (with VOIP – I always do that), but the cheap data SIMs are again with poor quality networks.
I think it costs about 1£ to send SMS to move EOBT by 1h using my UK number while in Sudan, AR pays $0.07 to reply as you said which is way cheaper
With my UK number in France, I pay 0.02£ per SMS and 0.01£ per 1Mb (max is 60Mb?), which is still cheap but not “free”
Actually when last on the UK I bought a Tesco pay as you go card. It has worked great in the UK and here in France. I’m getting voice calls in places I can’t get the call with Orange France (Which is AIUI the biggest network here.)
That sounds like the best way to do it while travelling but you rarely find “pay as you go SIM” for sale after landing GA airports? you simply rely on your phone, untill you get WIFI in your hotel or restaurant
If you land in Nice, Lille, Nantes, Southend, Cardiff…you can go to Starbucks to pick a coffee while installing SIM card you just bought, while at it get 25€/day car rentals
I think it costs about 1£ to send SMS to move EOBT by 1h using my UK number while in Sudan,
Very possibly. Or £100 to send it to an Iridium phone 
AR pays $0.07 to reply as you said which is way cheaper
Only to German (or possibly European) numbers.
Actually when last on the UK I bought a Tesco pay as you go card. It has worked great in the UK and here in France
Tesco is ok for those
in places I can’t get the call with Orange France
Orange was called “Zero Range” and for good reasons. I was with them for years.
Anyway, we have multiple threads on GSM networks. I think the AR dropping SMS is reasonable, given it is free.
