---
kind: "section"
citation: "14 C.F.R. § 27.1027"
title: "14"
number: "27.1027"
heading: "Transmissions and gearboxes: General."
url: "https://uscodex.org/cfr/14/27.1027"
---

# §27.1027. Transmissions and gearboxes: General.

- (a) The lubrication system for components of the rotor drive system that require continuous lubrication must be sufficiently independent of the lubrication systems of the engine(s) to ensure lubrication during autorotation.
- (b) Pressure lubrication systems for transmissions and gearboxes must comply with the engine oil system requirements of [§§ 27.1013](/cfr/14/27.1013.md) (except [paragraph (c)](#c)), 27.1015, 27.1017, 27.1021, and 27.1337(d).
- (c) Each pressure lubrication system must have an oil strainer or filter through which all of the lubricant flows and must—
  - (1) Be designed to remove from the lubricant any contaminant which may damage transmission and drive system components or impede the flow of lubricant to a hazardous degree;
  - (2) Be equipped with a means to indicate collection of contaminants on the filter or strainer at or before opening of the bypass required by [paragraph (c)(3)](#c-3) of this section; and
  - (3) **Be equipped with a bypass constructed and installed so that—**
    - (i) The lubricant will flow at the normal rate through the rest of the system with the strainer or filter completely blocked; and
    - (ii) The release of collected contaminants is minimized by appropriate location of the bypass to ensure that collected contaminants are not in the bypass flowpath.
- (d) For each lubricant tank or sump outlet supplying lubrication to rotor drive systems and rotor drive system components, a screen must be provided to prevent entrance into the lubrication system of any object that might obstruct the flow of lubricant from the outlet to the filter required by [paragraph (c)](#c) of this section. The requirements of [paragraph (c)](#c) do not apply to screens installed at lubricant tank or sump outlets.
- (e) Splash-type lubrication systems for rotor drive system gearboxes must comply with §§ [27.1021](/cfr/14/27.1021.md) and [27.1337(d)](/cfr/14/27.1337.md?p=d).

## Notes

### Amendments

[Amdt. 27-23, 53 FR 34213, Sept. 2, 1988, as amended by Amdt. 27-37, 64 FR 45095, Aug. 18, 1999]

### Authority

Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704.

### Source

Source: Docket No. 5074, 29 FR 15695, Nov. 24, 1964, unless otherwise noted.

### Amendments

[Amdt. 27-23, 53 FR 34213, Sept. 2, 1988, as amended by Amdt. 27-37, 64 FR 45095, Aug. 18, 1999]