Jam nuts serve a purpose and that is to prevent actuating arms from becoming disconnected. I found three examples on the same airplane. Two flap jam nuts were loose and should have been caught on a preflight, and the autopilot servo arm jam nut was loose as well. Any of these could cause a flight control problem if they came completely loose.
In Case You Missed It
The Staaken Z-21A Flitzer
Intended as an inter-war sportplane, the VW- or Jabiru-powered Staaken Flitzer delivers the goods in both performance and agility. These planes may not appear sleek, but they’re a blast to fly.
Cowl Plug Footballs
Nerf footballs give their all for flight safety. By Bill Repucci.
Loctite and safety wire , I have yet to have one come loose