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
Spread Those Sheets
I'm kind of loose with my engineering and teaching. I don't have a lot of hard-and-fast rules.
Gross Weights and “Destroyed” Airplanes
Mel Asberry - 0
Where you you find the gross weight of an aircraft? And can you re-register an airplane that the FAA has deemed "destroyed?"
Maxing Out the Fun Factor
For those who have experienced it, the fun of going on a flying trip...
Loctite and safety wire , I have yet to have one come loose