Suppose I'm making an ILS approach in heavy snow. All the instruments completely freeze! The altimeter gives incorrect readings, if the auto throttle is engaged then the engine power rises to 100% the heading goes for a toss. Its virtually impossible to make an approach!
From my experience I know that I need to engage de-ice which I'm already doing around 5 min before decent at 25k.
Anything else I need to do to get rid of this?