OK, I've tried many combinations - it seems (as mentioned by some folks earlier)
- The departure point and destination must be TK destinations (including some codeshare destinations). https://en.wikipedia.org/wiki/List_o...s_destinations
- The connecting point does NOT have to be TK destinations; it can be any star hubs EVEN OUTSIDE the zone.
- Only round trip permitted (tried to decode the HTML and URL query - no luck
- Mixed carrier is permitted but maximum 2 segments (1 stop) - UNLESS it is TK+TK+Star (e.g. AC+TK+TK). This is a huge improvement.
- The miles required seems correct compared to standard main award table. https://www.turkishairlines.com/en-c...rds/index.html. Even though the footnote on the website was changed some time last year and now says "applicable mile amount for DIRECT flights with Star Alliance member airlines in the same region", you can still book in region flights with stops for the same amount of miles (e.g. 20K for Europe 2 to 2).
- The TK in region to EUR1 zone 7.5K per way is displayed correctly, and you can book TK+Star in region award for the same 7.5K (even transit outside the zone, e.g. ATH-ZRH-IST)
- Domestic 7.5K one way with Star is not working. I didn't expect TK to recognize airports in the same country outside Turkey anyway...
- NO FUEL SURCHARGE on AC (HUGE for me if bookable), UA, SQ, CA, but YQ is calculated on LH, TK, and TK+Star tickets.