330/340 42-03 Front Windshield Heating One may be inoperative provided: The aircraft is not operated in icing conditions.
B747 30-11 Flight Deck Window Heating
1) #1 Windows One may be inoperative provided:
a) #1 left window heat is operative for LWMO,
b) Flight is not dispatched into known or forecast icing conditions,
c) Windshield air (anti fogging) is operative, and
d) Both #2 window heaters operate normally.
B747-400 30-41-2 FLIGHT DECK WINDOW HEATER SYSTEMS (#1 & #2)
One #1 or one #2 window heater may be inoperative provided:
a) Operation is not predicated on flight into known or forecast icing,
b) Windshield air (anti-fog systems) operates normally, and
c) Remaining #1 AND #2 window heaters operate normally
B777 [30-41-1 Flight Deck Forward Window Primary Heater Systems
One may be inoperative provided:
a) Associated window backup heater operates normally,
b) Both left and right side (#2) window heaters operate normally,
c) Aircraft is not operated in known or forecast icing conditions, and
d) For a cracked outer glass ply, limit airspeed to 280 KIAS or less below 10,000 FT MSL