The discussion at
http://www.pprune.org/tech-log/53670...ocedure-3.html might relate to this incident.
Has anyone a link to the "Boeing Flight Operational Technical Bulletin on the subject of unreliable airspeed issued dated 4 June 2013" as referenced in the report at para 2.6 (page 43 - 44).
For info see
Flight Operational Technical Bulletin Ice Crystals.