Text in force at CS29-12: from CS29-0, effective 14 Nov 2003.
(a) The air induction sy stem for each engine and auxiliary power unit m ust supply the air required b y th at en gine an d au xiliary power unit under the operating conditions for which certification is requested.
(b) Each en gine an d au xiliary p ower unit air induction system must provi de ai r for proper fuel metering and m ixture di stribution wi th t he induction system valves in any position.
(c) No air intake may open wi thin the engine accessory section or within other areas of any powerplant com partment where em ergence of backfire flame would constitute a fire hazard.
(d) Each reciprocating engine m ust have an alternate air source.
(e) Each alternate air intake m ust be located to prevent the entrance of rai n, i ce, or ot her foreign matter.
(f) For turbine engine powered rotorcraft and rotorcraft incorporating auxiliary power units:
(1) There must be m eans to prevent hazardous quantities of fuel leakage or overflow from drai ns, vent s, or ot her components of fl ammable fl uid sy stems from entering th e en gine o r auxiliary power unit intake system; and
(2) The air in let d ucts m ust b e located or protected so as t o m inimise t he i ngestion of foreign m atter duri ng t ake-off, l anding, and taxying.
ED Decision 2003/016/RM · Source