OPERATORS HAVE REPORTED AIRSPEED DISCREPANCIES WHILE FLYING UNDER HEAVY PRECIPITATIONS OR FREEZING CONDITIONS, WHICH SOMETIMES LED TO THE A/THR AND THE AP DISCONNECTION, THE E/W "F/CTL ADR DISAGREE" AND "F/CTL ALTN LAW"........
STRONG CUMULO-NIMBUS CONTAINING A HIGH DENSITY OF ICE CRYSTALS CAN BEE ENCOUNTERED, PARTICULARLY IN THE INTERTROPICAL CONVERGENCE ZONE (ITCZ)
IN SUCH AND ICY AND TURBULENT ATMOSPHERE, THE A/C AIR DATA PARAMETERS (PRESSURE DEPENDANT) MAY BE SEVERELY DEGRADED, EVEN THOUGH THE PROBE HEATERS WORK PROPERLY.
IT HAS APPEARED THAT THE CHARACTERISTICS OF SUCH AN ENVIRONMENT COULD EXCEED THE WEATHER SPECIFICATIONS FOR WHICH THE PITOT PROBES ARE CURRENTLY CERTIFIED.
