14 C.F.R. § 29.161 Trim control.
Title 14 - Aeronautics and Space
The trim control— (a) Must trim any steady longitudinal, lateral, and collective control forces to zero in level flight at any appropriate speed; and (b) May not introduce any undesirable discontinuities in control force gradients. [Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as amended by Amdt. 29–24, 49 FR 44436, Nov. 6, 1984]
Title 14: Aeronautics and Space
PART 29—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT
Subpart B—Flight
Flight Characteristics
§ 29.161 Trim control.