Da AVHerald :
“need to say Pitot tubes (actually its input reservoir) on this aircraft are heated with nichrome wires, which can be overheted easily and damaged. so it's not allowed to use heating more that one minute on ground. the heating should be turned on 1 min before take-off in summer time, and 3 min if air temperature is 0C and below, like now”
“If Pitot tubes heating was off, there (normally) must be bright warnings on displays in front of pilots. An-148 experts say it's very hard not to notice them.”
“ "Turn on Pitot tubes heating" item is present in the Before takeoff checklist of An-148.“