Originally Posted by
AerocatS2A
The problem isn't performance per se, it's having the data to quantify the performance. If your take-off performance data tops out at 50ºC / 122ºF (as ours does) then you can't go flying when the temps are hotter than that. If it tops out at 45ºC, then that's your limit.
Is it not likely that the take-off performance data tops out where it does because that's the limit that the aircraft can operate with a reasonable payload? Although not impossible, wouldn't a manufacture be silly to build an aircraft for ISA+45ºC and only certify it to ISA+35º.