Sorry, late to this thread, but many years ago in a B737/200 over N Wales around FL370, inbound to MAN, the A/P pitch channel dropped out for no apparent reason (1 A/P, separate Pitch & Roll channels --High Tech stuff). It was duly re-engaged and a few seconds later dropped out again, again with no warnings. Last try attempted, and stayed in for a few seconds, under close supervision, then once more out she goes, but his time with the Skipper's hands on the stick and a lot of attention we saw/heard there was a momentary stick shake (Stick Shaker activation automatically takes out the A/P Pitch channel).
Continued to MAN uneventfully, and were sitting on the ramp with the Tech Log out, wondering how to write this up so it made some sense, when the Ground Engineer arrives. Seeing our puzzlement he says "Autopilot Pitch Channel?" we both nod. "OK" he says, "Write `FL3X0 over N Wales. Repeated A/P Pitch Channel disconnects with momentary Stick Shaker activation'. "How do you know that?" we ask.
"Third today, the military must be up to something around the LLanbedr ranges!" (Lots of live ranges, radars etc in that area).
Different A/C. Different place and time, but similar results.
Fragman
