14 C.F.R. § 29.1551 Oil quantity indicator.
Title 14 - Aeronautics and Space
Each oil quantity indicator must be marked with enough increments to indicate readily and accurately the quantity of oil.
Title 14: Aeronautics and Space
PART 29—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT
Subpart G—Operating Limitations and Information
Markings and Placards
§ 29.1551 Oil quantity indicator.