14 CFR §23.2300

1. (a)The applicant must design airplane flight control systems to:
   1. (1)Operate easily, smoothly, and positively enough to allow proper performance of their functions.
   2. (2)Protect against likely hazards.
2. (b)The applicant must design trim systems, if installed, to:
   1. (1)Protect against inadvertent, incorrect, or abrupt trim operation.
   2. (2)Provide a means to indicate—
      1. (i)The direction of trim control movement relative to airplane motion;
      2. (ii)The trim position with respect to the trim range;
      3. (iii)The neutral position for lateral and directional trim; and
      4. (iv)The range for takeoff for all applicant requested center of gravity ranges and configurations.