---
title: "CS 25.1021 Oil system drains — CS-25 · Avioverse"
description: "A drain (or drains) must be provided to allow safe drainage of the oil system."
url: "https://avioverse.aero/regulations/easa/cs-25/subpart-e/cs-25-1021"
---

# CS 25.1021 Oil system drains

Large Aeroplanes (CS-25) · CS-25 · EAR revision 26 Jan 2023

IR Implementing rule

## CS 25.1021 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.

IR · CS 25.1021 — CS-25 · ED Decision 2003/2/RM · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

[All rules in SUBPART E – POWERPLANT](https://avioverse.aero/regulations/easa/cs-25/subpart-e)

Consolidated from the EASA Easy Access Rules (revision 26 Jan 2023, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.