Re avoiding storms (
lomapaseo #2535), “unfortunately this is often subjectively interpreted”. I agree, perhaps this is one of the significant differences in this accident – not flight in a Cb, but the margin by which the Cbs were avoided.
Re “Above the storm has been interpreted as good-enough yet is that not a greater risk to pitot, engines etc.?” The report linked in #2526 suggest that the icing conditions can occur above the storm. This together with weather radar weakness in detecting the vertical extent of the core and emerging cells beyond it would exclude Cb over-flight as an option.
EGMA re #2536, the central point in the ‘engine’ report (linked in #2526) is that perceptions or mechanism of conventional icing is not the same as ice particle icing; the latter can have a very sudden onset, see the plots of TAT rise.
The contribution (or otherwise) of drain holes is shown in the presentation
Instrument External Probes.
I do not know what the specific changes are between the different pitot designs; shape may be a critical factor or just a simple increase in anti icing heat flow, which was a fix for one of the engine types.
There is no evidence of any upset. It has been shown that the aircraft can be flown without airspeed information, and in other respects – lack of protections, structures, manoeuvre capability, etc, it is comparable with conventional aircraft.
Question: Aside from the debate on integrated automation and degraded operation, would the EFIS still indicate or be able to indicate the reversionary modes (alerts and cautions) with the supposed complete ADIRS shutdown?
If not, then the debate is not so much about gradual degradation of systems and basic control capability, it would be of the crew’s awareness of the change of state and triggering the need for knowledge of the required precautions.