CFR /  Title 14  /  Part 27  /  Sec. 27.1021 Oil system drains.

A drain (or drains) must be provided to allow safe drainage of the oil system. Each drain must--

(a) Be accessible; and

(b) Have manual or automatic means for positive locking in the closed position. [Amdt. 27-20, 49 FR 6849, Feb. 23, 1984]