AMC1 27.1301 Function and installation

• ED Decision 2023/001/R found in: CS-27 Amdt 10 - Small Rotorcraft (Feb 2023)

AMC1 27.1301 Function and installation ED Decision 2023/001/R This AMC replaces FAA AC 27-1B, § AC 27.1301 and should be used when demonstrating compliance with [CS 27.1301](#_DxCrossRefBm8894072). (a) Explanation It should be emphasised that [CS 27.1301](#_DxCrossRefBm8894072) applies to each item of installed equipment including optional as well as required equipment. (b) Procedures (1) Information regarding installation limitations and proper functioning is normally available from the equipment manufacturers in their installation and operations manuals. In addition, some other paragraphs in FAA AC 27-1B include criteria for evaluating proper functioning of particular systems — an example is § AC 27 MG 1 for avionics equipment.) (2) [CS 27.1301](#_DxCrossRefBm8894072) is quite specific in that it applies to each item of installed equipment. It should be emphasised, however, that even though a general rule as [CS 27.1301](#_DxCrossRefBm8894072) is relevant, a rule that gives specific functional requirements for a particular system will prevail over a general rule. Therefore, if a rule exists that defines specific system functioning requirements, its provisions should be used to evaluate the acceptability of the installed system and not the provisions of this general rule. It should also be understood that an interpretation of a general rule should not be used to lessen or increase the requirements of a specific rule. [CS 27.1309](#_DxCrossRefBm8894074) is another example of a general rule, and this discussion is appropriate when applying its provisions. (3) If optional equipment is installed, the crew may be expected to use it. This may be the case of navigation capabilities (as, for instance, LPV capability) installed on VFR rotorcraft. Therefore, the applicant should define the optional equipment and demonstrate that it complies with [CS 27.1301](#_DxCrossRefBm8894072) for its intended function. In addition, the applicant should ensure that the optional equipment does not interfere with the other systems that are required for safe operation of the rotorcraft and that its failure modes are acceptable and do not create any hazards. [Amdt 27/10]