§29.1027 Transmissions and gearboxes:

General (a) The oil system for com ponents of t he rotor dri ve sy stem t hat requi re continuous lubrication must be sufficiently independent of the lubrication systems of the engine(s) to ensure: (1) Operation with any engi ne inoperative; and (2) Safe autorotation. (b) Pressure lubrication sy stems for transmissions and gearboxes must comply with the requirements of C S 29.1013, sub-paragraphs (c), (d) and (f) only , CS 29.1015, 29.1017, 29.1021, 29.1023 and 29.1337(d). In addition, the system must have: (1) An oil strainer or filter through which all the lubricant flows, and must: (i) Be desi gned t o rem ove from the lubricant any c ontaminant wh ich may damage t ransmission and dri ve sy stem components or i mpede t he fl ow of lubricant to a hazardous degree; and (ii) Be equi pped wi th a by pass constructed and installed so that: (A) The lubricant will flow at t he norm al rat e t hrough the rest of the system with th e strain er o r filter completely blocked; and (B) The release of collected contaminants i s m inimised by appropriate location of the bypass to ensure that collected contam inants are not in the bypass flow path; (iii) Be eq uipped with a m eans to indicate collection of contaminants on the filter o r strain er at o r before opening of the bypass; (2) For each lubricant tank or sum p outlet supplying lubrication t o rot or dri ve systems and rot or dri ve sy stem components, a screen to prevent entran ce into th e lu brication system of any object t hat m ight obst ruct t he flow o f lu bricant fro m th e outlet to the filter required by sub-paragraph (b)(1). The requirements of sub-paragraph (b) (1) do not apply to screen s in stalled at lu bricant tan k o r sump outlets. (c) Splash type lubrication sy stems for rotor drive sy stem gearboxes m ust comply with CS 29.1021 and 29.1337(d).