Sarcastic? Only partly.
Other posts suggested that it is prudent - do I dare say ‘good airmanship’ - to run the rudder trim through its full range and confirm the correspondence of physical position and indicated position during pre-flight. That suggestion was made in a context that implied the check was not aimed only at confirming the rudder trim is indicating the correct position for take off. The implication was that the check is also aimed at confirming the rudder trim system, including the trim indicator, is working correctly throughout its entire range.
Once you say that the point of that pre-flight action is to confirm that the trim system including the trim indicator is working correctly throughout its entire range, you’re acknowledging that you’re checking to confirm that there have been no random failures or maintenance or other interventions that may have caused the system and the indicator to malfunction. If that’s the point of the check, rather than just looking down and seeing that the rudder trim indicator is indicating neutral, it follows that all of the aircraft’s systems should be checked to the extent of their full functionality to confirm there have been no random failures or maintenance or other interventions that may have caused problems. It therefore follows that the PIC:
- should have run up the engines and operated all of the engine and propellor controls through their full range, then shut down and inspected the engines and propellers
- removed all the inspection panels necessary to confirm that no control cable was fraying
- drained and replenished fuel to confirm that calculated and indicated equaled uploaded, and
- done an aircraft re-weigh to confirm that the loading and CofG data for the aircraft remained accurate.
All aircraft systems and components could suffer random failures or be adversely affected by maintenance or other interventions. What’s so special about the rudder trim system, other than hindsight?