Milt, I do not know if the specific pitot head has been tested in the relevant icing conditions (#2511).
Some pitot heads, OAT, and TAT probes have been assessed in icing tunnels, and all installed systems should have been exposed to conventional icing during aircraft type certification.
There appears to be many facets to the problem of pitot icing in this instance; first it is not conventional icing.
The atmospheric conditions and likely mechanism of icing (as you describe) are discussed in
http://www.pprune.org/tech-log/37634...ml#post5027449 and the linked paper "The Ice Particle Threat to Engines in Flight".
There does not appear to be any industry standard against which a pitot could be tested in these specific conditions. Furthermore, in addition to the possibility that every design of pitot head will produce different results, so too could each location on differing aircraft types.
Ice particle induced icing appears to be greatly affected by the airflow characteristics prior to the probe – very small particles probably follow the airflow, but larger ones (and water drops) might cross the flow due to their higher mass.
Fortunately the conditions are rare, or that pilot’s previous avoidance of large Cbs has contributed to infrequent hazardous encounters. Changes in these aspects appear central to recent incidents and this accident – so what is different? The training and use of weather radar has been discussed elsewhere, as has pilot knowledge, attitudes, and behaviour. These probably have contributed, but in previous incidents the outcomes were significantly different and thus the range differing piloting standards should not have been a critical factor in this accident.
The above also appears to support the view that the loss of all pitot information is no greater risk that hazardous –
Instrument External Probes, and that the aircraft can be flow relatively safely for an appropriate period (average exposure to the conditions 5nm, max 135 nm - engine ref above). However, there may be ‘hidden’ assumptions about crew competence in severe atmospheric conditions, checklist design and use, lack of primary inst, aircraft condition, lack of radar, etc, – what should the safety requirements consider for an extreme adverse combination of factors?
Other certification standards define an adequate level of structural strength for inadvertent flight in severe weather. If (IF) the aircraft broke up in flight then at this time we do not know why, nor apparently do we understand any mechanism for such a failure – we must wait and see.
Meanwhile avoidance of large storms by a wide margin would be a prudent safety action.