DPD also required the fitting of a stick nudger on UK registered 747s. This was because, (I quote page 262) with the flaps up and a trim speed of 1.3Vs, after a small elevator force to start the speed reduction, the stick force falls to zero while the aeroplane quietly progresses all the way to the stall on its own. The fix was the nudger. This is a gentle stick force augmentor of about 16lbs in the nose down sense which operates when the stick shaker starts to operate and remains effective until the stick shake cancels. In a fairly rough and ready manner it restores the pre-stall longitudinal stability and satisfies the requirements at little cost and with no snags.
Since the very start of this whole debate on the 737MAX, I have always wondered why Boeing didn't try something similar rather than using the MCAS to drive the whole horizontal stabilser.