14 CFR § 33.37 - Ignition system.

---
identifier: "/us/cfr/t14/s33.37"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 33.37 - Ignition system."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "33.37"
section_name: "Ignition system."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "33"
part_name: "AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(g), 40113, 44701, 44702, 44704."
regulatory_source: "Docket No. 3025, 29 FR 7453, June 10, 1964, unless otherwise noted."
cfr_part: "33"
---


# 33.37 Ignition system.

Each spark ignition engine must have a dual ignition system with at least two spark plugs for each cylinder and two separate electric circuits with separate sources of electrical energy, or have an ignition system of equivalent in-flight reliability.