Ozexpat: Please expand. No our route guide does not mention them. I'm still curious as to their worth, especially as the ones I've seen are on an ILS RWY, illuminating at the same time as the G/S. Seems like a waste of amps/volts to me.
Sorry that I missed this
RAT 5, but the only reasons I've ever heard for having a double PAPI are :-
1. Redundancy; and
2. The previous installation was a T-VASIS.
I favour the redundancy argument, especially at international aerodromes, but this benefit is sometimes negated because both PAPI systems are left on when a faulty one should be turned off. Of course, this makes it a tad difficult for us to figure out which one is giving the right information.
