Who knew the Instrument Landing System had a nearly undetectable failure mode?

In 2000, a New Zealand flight nearly flew into rocks because the ground-based ILS transmitter was sending a diagnostic signal. It made an airplane think it was on the proper glide slope (leading to a runway threshold) regardless of its actual position/movement (leading toward rocks). It was a little like flying based on a VOT (VOR test) signal, which is designed for calibration of aircraft radios by always identifying itself as “to the south” (regardless of actual relative position).

Here is the investigation report, and subsequent safety video clip (part 1, part 2, part 3).

Youtube…. maybe Cringley is right, and Google was right, and it is the next huge thing.