Originally Posted by Small cog
ISTR from my flying the Twotter many, many years ago that there is an elevator trim / flap / interlink to prevent a recurrence of tailplane overstress during flap retraction.
That's not what the flap-elevator interconnect tab is there for. It is there to reduce the amount of force that the pilot needs to apply to the control column to maintain the same pitch attitude prior to retrimming the aircraft. There is a certification requirement (CAR 3, later SFAR 23) that sets a limit on the amount of force that is needed to maintain pitch attitude following flap extension or retraction but prior to retrimming. Without the interconnect tab, the DHC-6 would not have met that limit.