@PJ2
Momentary loss of airspeed information isn't an emergency, it is a minor abnormal that, according to the drill, requires setting the MCDU to the GPS page to monitor altitude and levelling off for troubleshooting which means get out the QRH for the pitch-power settings, and wait...
Well... not really. According to AF book (see BEA's report appendix 9), when
ALL IAS are unreliable "
sécurité du vol" must be considered "
affectée" and 5° NU/TOGA drill MUST be performed.