@dosmarder thanks, yep that's exactly the part that caught me. I think it makes sense for the manufacture to simplify the models differences and the certifications and training required.
From my humble real-life C172 experience, even a modest diff of 160HP vs 180HP models can feel quite different, especially when torque and p-factor are at their fullest.
As I understand, the goal was to focus on the cruise performance without dealing with the rest of the flight envelope. While I'm also a bit puzzled about the lack of 850 mode during takeoff ( and go-arounds!) , I guess they considered the available performance for T/O GA balanced, proven and well in the design goals.
Another hint I've found, relies in the differences between the 850 and 900 where the 850 SHP made available for the entire flight regime. Here is an excerpt:
"The new dorsal fin and a new torque limiter on the PT6A allow takeoffs at the engine’s fully flat-rated 850 shp instead of the 700 shp limitation in the earlier TBMs. " https://www.ainonline.com/aviation-news/business-aviation/2014-07-01/pilot-report-daher-socata-tbm-900
My another hint also comes from the 850 POH, especially interesting to read is the restriction to use "850" during a go-around:
GO--AROUND (2/2)
If IAS is at or above 115 KIAS :
8 -- Flaps ................................................ UP
In case of air leak between the solenoïd valve and the torque limiter,
the available torque might be below 100 %. Consequently, it is
strongly recommended not to select “850” :
for a new approach or visual circuit
for staying below 1500 ft AGL
Just my guessing here, but it seems that the torque limiter is a sensitive point of failure and again in the balance of safety vs performance it is best to stay on 700SHP.. my interpretation anyways...
