Nelson-Auckland is scheduled at 1:25, with the upper level wind yesterday taking close to 2 hours seems about right.
The normal cruise rpm of Dash is pretty low so when ice starts to build up there can be a decent vibration, bringing the props up to max rpm is quite effective at getting the ice to shed. Yes there is electric prop de-icing but it can only do so much.
Yesterday that upper air flow was more NW so slightly warmer and at FL180 would have been nicely within the -10 to -20 C zone where ice accretion is more likely. -30 to -40 aren't such a worry for icing because there is very little moisture left at those temperature, if performance allows it can be better to climb above that -10 to -20 C zone if you start picking a fair bit of ice.
Last edited by Massey058; 9th Jul 2018 at 01:58.
Reason: grammar