In the 1970s we were not permitted to alter flap settings in the Viscount whilst turning. We were told that the aeroplane had previous form with assym flap.
I remember that very well because, flying a tight arrival the voice from the LHS announced "I hope you aren't planning to extend flap in the turn, Basil, because you know it isn't allowed!" Bas had forgotten that The Boss was commanding that sector.
