Trim runaway was a possible scenario identified by the Air Accidents Investigation Branch in a report into a 2017 Piper PA-31 fatal accident.
The pilot reported pitch control problems and diverted to Caernarfon Airport where the aircraft crashed on an attempted landing. The elevator trim was found in a significantly nose-down position.
You can read the full AAIB report in the AAIB March 2019 bulletin.
To help pilots prepare for a trim runaway we have produced a short guidance document called Handling a trim runaway (CAP 1774).
The short videos below explain the issue, how to deal with a runaway and what you can do now to make sure you're prepared for any incident.