cockygashandlazy,
It's a journo writing. IMHO a temperature rise of 20 degrees C to minus 34 degrees C at 41,000 ft can only be explained by assuming an anomaly of the temperature sensor, which is a common occurrence in these incidents, see the Mason paper.
EDIT:: A TAT sensor is enclosed in a heated duct, susceptible to accretion of ice particles by the same mechanism as engine internal ducts and vanes.
Last edited by HazelNuts39; 27th Aug 2013 at 12:55.