On most airplanes, you can trim the elevator by turning a wheel or crank that sets a tab — a flap on a flap — that then redirects the airflow to hold the elevator or stabilator at a certain angle of attack. Elevator trim is fairly important, since it saves you from having to hold constant pressure on the yoke to keep the plane from diving to the ground or going nose up and stalling. Fancier planes also have rudder and aileron trim (the Warrior has a fake rudder trim that’s really just a spring in the control system).
Since I bought my Piper Warrior II in December 2002, the elevator trim wheel has been surprisingly hard to move. Sometimes I almost get used to it, but then I fly another plane and notice that the wheel does not require 20+ lb of force to turn. At every annual inspection, I’ve squawked the trim, and mechanics have replaced the cable, replaced the pulley, and tried various lubricants. It always seemed a bit easier afterwards, but then soon went back to its old self.
This year, I squawked the trim once again, but the mechanic wasn’t satisfied just relubing; instead, he decided to examine the trim tab itself, and he noticed that when you turn the trim wheel, the tab flexes, but that the hinge has seized up with corrosion and does not seem actually to move. I imagine that it has been moving some — since it also acts as an anti-servo tab, the plane would be tricky to control otherwise, and I’m sure that I verified at least some movement on every preflight — but it’s still strange to think that I’ve been flying single-pilot IFR with no autopilot and trimming my plane by flexing aluminum through brute force alone. Man vs. machine, indeed.