Critical engine
14 CFR § 1.1 — Definitions
Official definition — 14 CFR Part 1
REGULATION — OFFICIAL DEFINITIONCritical engine means the engine whose failure would most adversely affect the performance or handling qualities of an aircraft.
Reproduced verbatim from the eCFR. Regulatory definitions control how the term is used throughout 14 CFR.
Is this a regulation?
Yes — this is regulatory text and is legally binding.
Definition published in 14 CFR Part 1. Regulatory definitions are legally binding wherever the defined term is used in 14 CFR.