anchorhold,
The Tucano does not have an abnormal history of trim runaways and I cannot remember why this training requirement was introduced. It has a 'Trim Isolate' switch which cuts out the trims in all 3 axes simultaneously. I have had an intermittent pitch trim runaway in one whereby it ran away but I was able to then trim back. After a couple of minutes it did it again so I retrimmed to what I thought were the trim settings required for the approach and selected Isolate. The landing was uneventful.
Rgds
L.