Recently an experienced pilot told me that he flies practice instrument approaches (flying school stuff) with a fully shut down engine, for MECIR training.
The RAAF learned the folly of that over 55 years ago after several crashes where propellers were feathered for practice asymmetric landings and engine failures after take off. There were two major crashes at Townsville three years apart but for the same reason. These were Lincoln four engine bombers where an outboard engine was cut and its prop feathered for landing.
In the first instance the instructor was an experienced former wartime Lancaster pilot who only nine years earlier had won a DFC when his Lancaster was hit by another Lancaster at night during a raid over Germany. Not only did he have part of one wing torn away, but lost two engines. He felt it was safer to continue to the target on two engines using almost full aileron and rudder (in IMC single pilot by the way) than do a 180 and risk a head on collision with one of a few hundred Lancasters of the incoming bomber stream.
But I digress. The point being he was an experienced multi-engine flying instructor and a good one too. I know, because I flew with him many times at Townsville. The pilot he was converting at Townsville was a experienced wartime pilot, so he was no sprog CPL in a Duchess. The instructor was demonstrating a feathered landing in the usual 10 knot cross wind on 02 at Townsville (the old wartime runway) and because of the poor visibility over the nose of the Long Nosed Lincoln (worse still at night), he found himself straddling the left edge of the runway during the hold off with No 1 feathered. He went around again but below VMCa.
By dint of full rudder and considerable aileron he was able to keep it clear of the ground but the aircraft continued in ground effect in a half circle around the aerodrome boundary until it hit a power pole. The Lincoln crashed and caught fire but the three man crew escaped with minor injuries. The Court of Inquiry blamed the accident on pilot error which of course it was. But in those days feathered practice asymmetric landings were the norm in training.
Then a few years later, another instructor was training new pilots (they had about 230 hours and the Lincoln was their first multi engine type). This was at Townsville, too. On final for 20 this time with the port outboard feathered for a practice asymmetric landing. The Lincoln bounced (and my, how a Lincoln could bounce...) and the instructor (by coincidence another wartime Lancaster veteran) took over and tried to cushion the bounce by applying power on the remaining three engines and letting the aircraft down gently. The asymmetric yaw got too much and he tried to go-around. VMCa all over again and the Lincoln crashed and burned. No casualties although it was close to the then civilian terminal. Pilot error once more was the verdict.
By now the RAAF brass had had enough and belatedly brought in an Air Force directive that practice asymmetric landings were to be confined to throttled back zero thrust only. Meanwhile in civilian flying feathered landings continued to this day with the loss of many aircraft and lives.
OK, so todays instructors on the Duchess and Seminole are not expected to know history of old accidents- but that doesn't preclude the use of good old fashioned airmanship and commonsense - or it shouldn't. But I sometimes wonder!