Further info on LED's and WAI... Confirmed that Lufthansa also has the LED inhibit (mentioned in their FCOM)
Looking at the WAI circuit.. The inhibit is only active with the Wing Anti Ice switch in AUTO (another 744 option). The signal from the left and right ice detectors is inhibited if any of the three FCU's sense that the Flaps are not up.
Thanks, Dan. You're stretching my memory, but our classics only had one battery for the electrical system (one for APU starting and control).
Rgds.
NSEU