This is an excerpt from a report made to the Aviation Safety Reporting System. The narrative is written by the pilot, rather than FAA or NTSB officials. To maintain anonymity, many details, such as aircraft model or airport, are often scrubbed from the reports.
My student and I departed on a mini cross-country in the Cessna 152. When I took the controls so my student could get his charts out (approximately seven miles away from the airport), I noticed that the trim wheel could only be progressively moved in the nose down position.
At some point I had to apply quite a lot of yoke aft pressure to keep the plane in straight and level flight. I made a 180, and let ATC know the situation.
On the way back for landing, my student appeared to have forced the nose trim wheel downwards in order to get some nose up trim action and we heard a loud snapping or cracking noise. After the noise, the trim wheel operated normally, and we were able to fly the plane no issues and land uneventfully.
We landed and downed the plane so our mechanic could look at it.
I can’t imagine a student solo or a low time private pilot dealing with this situation well.
Not sure if this was a factor, but we were the first flight after maintenance was done to repair the carb heat control.
Primary Problem: Aircraft