Originally Posted by
slacktide
On the NG, it is possible for the STS to fail in a way that causes undesired intermittent runaway trim, just like it is possible for MCAS to fail in a way that causes undesired intermittent runaway trim. Clearly, due to the reliance on a single unchecked AOA value, the demonstrated failure rate has been orders of magnitude greater on the MAX. But the scenario of intermittent runaway trim is still possible on NG.
I have been searching high and low for any actual cases of this happening on the 737NG, particularly as a result of a bad AOA or airspeed input in much the same way as occurred in the MAX accidents. If anyone has an actual case history of this malfunction, please post it here or send me a PM.