There does, however, remain a worrying airworthiness issue.
The enquiry has revealed that improper washing techniques can allow water to penetrate the alpha sensors leading to a multiple sensor failure.
A multiple failure will not be correctly interpreted by the automation and in this case apparantly caused a control law change and a full-up elevator trim which was not immediately apparant to the crew.
Complex failures of this kind are difficult to diagnose and indeed are difficult to design around. I find it worrying that a simple error by relatively unskilled ground staff can lead to such a situation.
Alpha limits should never be triggered in normal airline operations but the protection is there for good reasons and there remains a possibility that the failure could be repeated with disastrous results.
Strict supervision of washing operations is the obvious answer but a redesign of the sensors and pilot awareness are also important.
Another case of the world inventing a better fool to defeat a supposedly foolproof system.