Hm.... yes, the 747-8 has many of everything. It even has a system that protects against tailstrikes and looks a bit like the 737-Max system that didnīt work right at first. I wonder how the 3 LRRA cope with the 5G stuff...?
Originally Posted by
tdracer
Rather ironically given the current issue, WOW (prox sensors) was not considered sufficiently robust with regard to ElectroMagnetic Interference and is typically single thread. LRRA designed and certified as a Critical "DAL A" system and nearly always has redundancy.
When we did the 747-8, we used a combination of WOW and LRRA for critical engine control functions - basically five sources (two WOW, three LRRA) - to indicate "On Ground" for critical functions we required three on-ground indications, with at least one each from WOW and LRRA.