GB, my experience is with TAT probe icing and engine malfunctions in similar conditions, but essentially these involve the same phenomena as the ‘pitot icing’ hypothesized in AF447.
As you are aware, this form of ‘icing’ is not conventional icing and is better described as ice particle icing, where very small particles accumulate in unheated parts of tubes, or freeze / refreeze where melting ice balances the heat flow of anti-icing devices.
The conditions where these very small particles are encountered were outside of the then normal icing certification envelope and thus did not have to be considered by manufacturers. Until relatively recently the science of icing did not recognize or predict such conditions.
The particle size, shape, composition are such that they are most unlikely to be reproduced by tanker aircraft. During the early investigations, the only facility capable of reproducing the conditions was at the Arnold Test Centre and involved liquid nitrogen in a wind tunnel.
The relatively ‘recent’ spate of problems from ice particle icing begs the operational questions why now? What has changed?
Some considerations, but not exhaustive:
- Older aircraft did not have sufficient performance to reach the conditions (EASA - European Aviation Safety Agency slide 17), possible, and/or with a lower number of exposures, but perhaps the older systems (and engines) were more tolerant to these conditions.
- Older aircraft did not fly in the conditions generally found close to large Cbs. Quite possible. Modern WXR provide crews with high quality information (but still not detecting ice); this could lead to a false sense of security, or overconfidence from routine operations. These, together with the pressure of modern operations / ATC / airspace restrictions could result in cutting Cb deviation too close.
- Modern aircraft use sensors to provide (digital) data for many systems other than primary flight instruments, thus any malfunction (severe ice particle encounter) can have a wide ranging and noticeable effect.
http://www.ukfsc.co.uk/files/Safety%...Oct%202009.pdf
http://www.specinc.com/publications/...craft_1998.pdf
http://www.sae.org/events/icing/pres...sopenmason.pdf