Peter, based upon the majority opinion of the TC members the rendering you put up the blue area part of the seatback would not pass
The area being measured is the “Flat” portion. The top area of seat specification you show is correctly displayed by the top of green line on centerline.( assuming green line having the min 2″ radius and being located at top of flat area “Crown”)
The issue here is that flat area does not extend out to the tangent to the curved green line everywhere . Therefore seat as shown is too narrow
Edge radi along top of seat to support is not considered part of the measured seat .
currently there is no constraints to a support structure
The seat back specification in the past and currently in effect essentially is the green line . Any flat area to either side of center extending beyond the green line is open The green line area is the minimum requirement
As far as Paul’s comment about “padding ” applied to seats I agree, the seat back must conform to specification prior .
At this time I believe we can consider this discussion concluded and deemed “clarification” As the majority are in Agreement