Wx radar
having stayed out of the debate .. which remains my policy until findings are released by BAE, I wish to add my comments regarding weather radar from personal experience.
If it is not pointed at the correct part of the cloud, there will be no return, ie no water droplets to give a return. It means scanning a vertical profile from surface (clutter) returns upwards to get a vertical section through something active.
My ex, working as c/c along with her colleagues were horribly bounced over the roof structure and galley areas because flying in high overcast with no look down, a very active cell failed to paint. One girl was medivac'd out and never flew again having flown 4 rows forward from the aisle and head first into the 'F' foot well.
Own experience from the flightdeck, the number of times I entered "WX radar failed to paint visually active TS cells" together with the Fl, range, angles, and gain used, only to have it signed off as "tested on ground found satis" are too numerous to mention.
Of the manufactures mentioned one was worse than the other in this respect, & I will leave it at that.