I wonder if the OP is confusing ‘Icing’ conditions with ‘Freezing’ conditions? I am currently mid-way through line training on the 737NG (having come from regional jets and turbo-props.) Our fleet is a mix of ‘mid-life’ (up to 20 year old, and new aircraft.)
Probe heats aren’t automatic on ours.
We have supplementary procedures for freezing (temp 3•C or less, wet runway and / or visible moisture) as distinct from ‘icing conditions’ mentioned by the OP. We performed them yesterday. Freezing conditions supplementary procedures include turning the probe heats on before start, and performing a 70% N1 runup for 30 seconds on the seconds on the runway before brakes release and TOGA being pressed.
But clearly, I appreciate different operators have varied definitions and procedures, so obviously, go with what’s in your manuals (or ask a Trainer to clarify.)
Last edited by Jump Complete; 28th Feb 2020 at 10:07.