14 C.F.R. § 29.871 Leveling marks.
Title 14 - Aeronautics and Space
There must be reference marks for leveling the rotorcraft on the ground.
Title 14: Aeronautics and Space
PART 29—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT
Subpart D—Design and Construction
Miscellaneous
§ 29.871 Leveling marks.