17000m is normally on the high side for the tropopause, even in the tropics (was it that high for AF447?).
Possibly a handwritten 1 has been transcribed as 7.
...m.......ft......°C
10999 36089 -56.3 ISA at tropopause
10668 35000 -54.1 ISA (AF447 - forecast -46°C)
09448 31000 -46.2 "