Fabien, I guess that was a "national" exception..based in the French Navy F10 "Mer" cockpit mods, and before the new 25 rules had been written…

I'd guess nobody, neither the FAA nor EASA would open that can of worms, because of the danger of Michael O'Leary of Ryanair fame then starting to bug our friends in Renton to produce a "NEOphyte Single Pilot" version of the 737…

and then he would start ads…."Flights from Vienna to Paris for 10 Euros, we've got one pilot on board, no lavs, you bring your diapers and your own fuel…"

never quite got it, how and why O'Leary ended up in the airline biz…he'd be the perfect sales- and marketing man for robotic lawn mowers….

If I recall correctly, the original Diamond was designed to be single pilot. As a matter of fact that is why the CB panel on the Diamond 1/1A, 400A and 400XP are on the left side of the cockpit.

I think the aircraft was overweight by the time they were done and that is why they nixed the single-pilot authorization......

Just to expand on what we were saying, I just realised that I know of one more example of a FAR/CS25 airplane which is SP.

The C501/550.

And it's even certified SP in EASA-land, where you can get an SP and MP rating, the two being completely different ratings. And it's still a CS25 plane, with an MTOW>5.7t/12500lbs.

Next question, are there SP and MP version of the plane?