---
kind: "section"
citation: "14 C.F.R. § 21.128"
title: "14"
number: "21.128"
heading: "Tests: aircraft engines."
url: "https://uscodex.org/cfr/14/21.128"
---

# §21.128. Tests: aircraft engines.

- (a) Each person manufacturing aircraft engines under a type certificate must subject each engine (except rocket engines for which the manufacturer must establish a sampling technique) to an acceptable test run that includes the following:
  - (1) Break-in runs that include a determination of fuel and oil consumption and a determination of power characteristics at rated maximum continuous power or thrust and, if applicable, at rated takeoff power or thrust.
  - (2) **At least five hours of operation at rated maximum continuous power or thrust.** For engines having a rated takeoff power or thrust higher than rated maximum continuous power or thrust, the five-hour run must include 30 minutes at rated takeoff power or thrust.
- (b) The test runs required by [paragraph (a)](#a) of this section may be made with the engine appropriately mounted and using current types of power and thrust measuring equipment.

## Notes

### Amendments

[Doc. No. 5085, 29 FR 14568, Oct. 24, 1964, as amended by Amdt. 21-5, 32 FR 3735, Mar. 4, 1967]

### Source

Source: Docket No. 5085, 29 FR 14568, Oct. 24, 1964, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7572; 49 U.S.C. 106(f), 40105, 40113, 44701-44702, 44704, 44707, 44709, 44711, 44713, 44715, 45303.

### Amendments

[Doc. No. 5085, 29 FR 14568, Oct. 24, 1964, as amended by Amdt. 21-5, 32 FR 3735, Mar. 4, 1967]