---
kind: "section"
citation: "14 C.F.R. § 38.11"
title: "14"
number: "38.11"
heading: "Fuel efficiency metric."
url: "https://uscodex.org/cfr/14/38.11"
---

# §38.11. Fuel efficiency metric.


For each airplane subject to this part, or to determine whether a modification makes an airplane subject to this part under the change criteria of [§ 38.19](/cfr/14/38.19.md), a fuel efficiency metric value must be calculated, using the following equation, rounded to three decimal places:


## Notes

### Authority

Authority: 42 U.S.C. 4321 et seq., 7572; 49 U.S.C. 106(g), 40113, 44701-44702, 44704; 49 CFR 1.83(c)

### Source

Source: Docket No. FAA-2022-0241, Amdt. No. 21-107, 89 FR 12654, Feb. 16, 2024, unless otherwise noted.