14 C.F.R. § 121.241 Oil system drains.
Title 14 - Aeronautics and Space
Accessible drains incorporating either a manual or automatic means for positive locking in the closed position, must be provided to allow safe drainage of the entire oil system.
Title 14: Aeronautics and Space
PART 121—OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS
Subpart J—Special Airworthiness Requirements
§ 121.241 Oil system drains.
