Just Read this analysis from CAPA about TG considering introducing Premium Economy. It also details about other airlines in SEA that offers PE, including PAL. One of the quotes states the following
"PAL retrofitted eight A330-300s with premium economy from 2Q2017 to 1Q2018. PAL’s first new aircraft with premium economy, an A350-900, was delivered on 14-Jul-2018. PAL will take three more A350-900s by the end of 2018 and two more A350s in 2019"
By the end of 2018 PAL will just have 12 aircraft that will feature PE which consist of 8 A330-300, and 4 A350-900. If the delivery of the 2 remaining A350 included that will rise to 14 aircraft. From this it looks liked the 7 Bi-class A330s will liked stick around for a while longer. However what I find more Intresting is the next quote.
"PAL (at least for now) has no plans to retrofit its 777-300ER fleet with premium economy, which would enable the airline to offer a more consistent product across its long haul network."
From this quote it seems that there is no definitive plans to retro-fit the B77W with PE (not sure if they have plans to replaced the J and Y seats on the 6 older B77W Probably included.) I'm quite baffled by this since the B777 is there biggest aircraft yet there no solid plans to retrofitted them With PE (Let alone replaced The J and Y seats in there six earlier B77W which are starting to get warn out.) also this aircraft are being used at there flagship routes yet there onboard product are dated.
Link to the analysis:
https://centreforaviation.com/analysis/reports/premium-economy-thai-airways-considers-joining-the-growing-trend-428540<quote