(a) The air induction system for each engine and auxiliary power unit
must supply the air required by that engine and auxiliary power unit under
the operating conditions for which certification is requested.
(b) Each engine and auxiliary power unit air induction system must
provide air for proper fuel metering and mixture distribution with the
induction system valves in any position.
(c) No air intake may open within the engine accessory section or
within other areas of any powerplant compartment where emergence of
backfire flame would constitute a fire hazard.
(d) Each reciprocating engine must have an alternate air source.
(e) Each alternate air intake must be located to prevent the entrance
of rain, ice, or other foreign matter.
(f) For turbine engine powered rotorcraft and rotorcraft incorporating
auxiliary power units --
(1) There must be means to prevent hazardous quantities of fuel leakage
or overflow from drains, vents, or other components of flammable fluid
systems from entering the engine or auxiliary power unit intake system;
(2) The air inlet ducts must be located or protected so as to minimize
the ingestion of foreign matter during takeoff, landing, and taxiing.
(Secs. 313(a), 601, 603, 604, Federal Aviation Act of
1958 (49 U.S.C. 1354(a), 1421, 1423, 1424), sec. 6(c), Dept. of
Transportation Act (49 U.S.C. 1655(c)))
[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as amended by Amdt.
29-3, 33 FR 969, Jan. 26, 1968; Amdt. 29-17, 43 FR 50601, Oct. 30, 1978]