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
ACN: 1839380
dont mess with operating equipment it causes failures
all that wear and tear on secondary controls
perhaps once a month or aft maint or at annual would b sufficient
forcing anything not good ( altho it works for iced up aileron gap seals on warrior)
original poster never says what mechanic found
I fly a 7KCAB and though it does not have a “trim wheel” for pitch trim (it has a sliding lever similar to a throttle) part of my pre-takroff check is to exercise the trim “stop to stop” before placing it to take off position. JMTCW
As an AMT and student pilot, I’d NEVER leave the ground before verifying that all controls were able to touch both stops. Especially after being in maintenance.
On preflight inspections and runups, typically the control wheel is moved to the aileron and elevator stops and the rudder exercised but not always to the stops. The trim is usually just verified to be neutral or at the takeoff mark. This is a good example that during the preflight, the trim wheel should be run to both stops and the trim-tab position verified outside the airplane (to make sure it reaches the stops and also that it doesn’t move backwards). Same goes for the fuel selector. How do you know you can switch tanks or turn off the fuel system in an emergency if you haven’t moved the control to all positions.