Can someone explain this paragraph from the A320 FCTM about minimum temperatures for non-precision approaches? I can't understand it.
COLD WEATHER OPERATIONS For all Non Precision Approaches, there is a minimum OAT. Below this temperature, the error on the barometric altitude is no longer acceptable, and altitude should be corrected in temperature. As it is not authorized to make these altitude corrections to the final approach segment of the FM Flight Plan (F-PLN) through the MCDU, it is not possible to use FINAL APP when OAT is below this minimum OAT. The flight crew must then use selected vertical guidance. This minimum OAT is indicated on the approach chart or must be defined by the operator based on the terrain profile (plus adequate margin).