Then there was the occasion of a 777 A/P responding to dud acceleration information from the ADIRU that nearly took everyone out. It was the manual flying skills of the PIC that saved the day.

Shivers that sounds nasty Lookleft, where and when was that?

That was an MAS 777 going from Perth to KL in August 2005. The ATSB has a report on it 2005 03722. One of the interesting aspects was that the cause was a design flaw in the software driving the ADIRU. While ever software is a major part of systems development a human will be required at the pointy end.

The Canberra bomber did not have an autopilot. It frequently flew at 45,000 ft on the basic six pack of flight instruments. Limited panel at those altitudes was a challenge. The RAF lost a Canberra en-route Manus Island to the USAF base at Kwajalein Atoll in the Marshal Islands in 1954. There were CB's tops 60,000 ft.in the ITCZ. It was never found. It was thought it may have had an electrical failure (it had happened before) resulting in the loss of both generators and thus loss of the AH. Two weeks later a replacement Canberra experienced loss of both generators in IMC on the same route but managed to obtain visual flight.

Toughen up, Boeing driver. We were flying a (smallish) 4-engined jet around the Indian Ocean for days with no AP a few years back!

Had the occasional "total" failure of the AP system in the Boeing I used to fly. We coped.

Affirmative.

Had a loss of entire AFDS (auto-pilot and flight director) in the B777.

Suspected ground interference caused failure of 2 Rad Alts, knocking the AFDS out for the rest of the flight. So much for the advice during training that it would never happen.

Going back a long while we used to fly one of our HS125 aircraft worldwide with no autopilot at FL410. Never seemed much of an issue except the extra workload. I did turn back once climbing out of Sydney on a 146 with an autopilot failure but that was on a return to the UK ferry.

Dispatching without an AP was fairly relaxed compared to a long day of IMC formation and tanking in a small jet. Although breakfast was a little rushed and we didn't finish the crossword.

To the OP, yes! In Boeing FBW aircraft, a downgrade from Normal flight control mode will render the autopilots inop. I know of at least one incident where this occurred due to momentary unreliable airspeed, and the flight control mode could not be reset to Normal. I found a precis of the event here: Serious incident Boeing 787-8 Dreamliner VH-VKE, Monday 21 December 2015

Yep. I've dispatched several times with no working AP or AT in a 737. Also done it in ATPs BAe146 and Q400. Not an issue. The 737 was while working in Turkey so Non RVSM and it was a domestic, though a longish one. Both F/O (Ex Turkish Army Helo pilot) and I had no issues and did both climb to TOC and part of the cruise and handed over to setup and brief then took back control.

Back in the UK I've also taken an aircraft with no AT, but that was a hand me down to prevent a delay as several other crews had rejected it. MAINTROL were pleasantly surprised! The F/O was quite nervous though, till we were on the way and he realised it was a non event. I guess we get into a comfort zone and don't want to do any work here in the Western world......

What a silly comment. I'd wager 95% of crews that reject an aircraft with no AP or ATS would do so because of safety concerns. The other 5% of rejectees would say "you won't let us hand-fly or with the ATS disengaged in normal operations so you can jam it when it's actually MELd". The FOQA god will also be watching. Will he be lenient if things get untidy when you don't use the AP or ATS because they are U/S?

Prior to the RVSM era, I flew an MD80 manually from Alicante to Stockholm at FL370 due AP failure. No issue really, except me and the Captain took turns in cruise to fly in order to let the other one eat and monitor a bit. My first airline gig was flying a regional turboprop in the U.S. without any AP/AT in all weather ops in congested airspace, so it felt as no big deal really..

I must be getting old, as I feel these days there is almost a sense of panic among the magenta generation if the AP is not engaged shortly after departure and kept on until fully configured/ trimmed out on short final....