If the FD was intermittently on and off, working and not working, I may have a better guess at the answer to my old question regarding the PF: what was he seeing?
If what I guess is close to right, then I begin to understand another factor in his confusion and frustration, particularly if his habitual instrument scan relied heavily on the "bird."
Mind you, this is guessing. Maybe a puzzle piece that fits better than others, maybe not.