Text in force at CS25-28: from CS25-0, effective 17 Oct 2003.
(a) Each oil line must meet the requirements of CS 25.993 and each oil line and fitting in any designated fire zone must meet the requirements of CS 25.1183.
(b) Breather lines must be arranged so that –
(1) Condensed water vapour that might freeze and obstruct the line cannot accumulate at any point;
(2) The breather discharge does not constitute a fire hazard if foaming occurs or causes emitted oil to strike the pilot’s wind-shield; and
(3) The breather does not discharge into the engine air induction system.
ED Decision 2003/002/RM · Source