Thai has already been putting in new seats on about half of their B747-400's. The aircrafts with the new style seating is mostly used on the routes to FRA and LHR. But it can varies. The best way to find out what configuration the actual aircraft has, is to use one of the search engines for booking tickets you find on the internet. You can do that from the TG homepage if you like.
The aircrafts with the old configuration is marked with 744 under aircraft type, while the ones with the new is marked with 747.
U are perfectly right about the route to CPH. The business pax are seated in the old F class section in the nose on the main deck. It is absolutely one of the better business class travels available. Food is served restaurant style from a trolley where you can see whats available and pick what you like. Seats are excellent for sleeping and service is very good. The only thing is that there is no personal TV's except small DVD players that you may borrow.
TG says they are giving first class service in the business class section on the CPH route. Only exception is no caviar and high-end champagne.
After 2 trips to BKK this year on this route, I would definatly choose TG c-class again for my next trip!
However, when they introduce the new seats on this route, they will go back to the tradisional layout. But no one can tell when that will be. I dont think they rush it, as from CPH there are a very low demand for F class. Before they change the configuration I was on several flights with empty F class. I have never been on a flight on this route with more then half-full C-class cabin eather. But monkey class have always been full or almost full.
Have a nice trip!
Alex
