14 CFR 33.69 : Aeronautics And Space (§ 1.1 To Parts 1311-1399) — (§ 1.1 To Parts 50-59) — Federal Aviation Administration, Department Of Transportation (§ 1.1 To Parts 50-59) — Aircraft (§ 21.1 To Parts 50-59) — Airworthiness Standards: Aircraft Engines (§ 33.1 To Appendix D To Part 33) — Design And Construction; Turbine Aircraft Engines (§ 33.61 To § 33.79) — Ignitions system.

4 Aug 2016

Each engine must be equipped with an ignition system for starting the engine on the ground and in flight. An electric ignition system must have at least two igniters and two separate secondary electric circuits, except that only one igniter is required for fuel burning augmentation systems.

14 CFR 33.69
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974]