AMC1 29.927 Additional tests

• ED Decision 2023/001/R found in: CS-29 Amdt 11 - Large Rotercraft (Feb 2023)

AMC1 29.927 Additional tests ED Decision 2023/001/R (a) Introduction This AMC supplements FAA AC 29-2C, § AC 29.927 and should be used in conjunction with that AC when demonstrating compliance with [CS 29.927](#_DxCrossRefBm1178331804). (b) Variable rotor speed (NR) (1) Explanation The variable rotor speed (NR) function allows running at different NR levels to achieve, for instance, lower noise levels and better rotorcraft performance. In addition to the endurance test prescribed in [CS 29.923](#_DxCrossRefBm1178331805), additional tests may be necessary to demonstrate that rotor drive systems of rotorcraft with a variable NR are safe. (2) Procedure In order to substantiate an acceptable vibration and dynamic behaviour of rotor drive systems when using the available range of rotor speeds within the variable NR function, the applicant should consider performing specific test investigations, as prescribed in [CS 29.927](#_DxCrossRefBm1178331804)(a). The need for representative test runs at the different torque and rotor speed combinations, covering steady states and transient conditions to be encountered in operation, should be evaluated by and agreed with the Agency. [Amdt No: 29/11] ##### AMC1 29.927 Additional tests *ED Decision 2023/001/R* (a) Introduction This AMC supplements FAA AC 29-2C, § AC 29.927 and should be used in conjunction with that AC when demonstrating compliance with [CS 29.927](#_DxCrossRefBm1685772269). (b) Variable rotor speed (NR) (1) Explanation The variable rotor speed (NR) function allows running at different NR levels to achieve, for instance, lower noise levels and better rotorcraft performance. In addition to the endurance test prescribed in [CS 29.923](#_DxCrossRefBm1685772270), additional tests may be necessary to demonstrate that rotor drive systems of rotorcraft with a variable NR are safe. (2) Procedure In order to substantiate an acceptable vibration and dynamic behaviour of rotor drive systems when using the available range of rotor speeds within the variable NR function, the applicant should consider performing specific test investigations, as prescribed in [CS 29.927](#_DxCrossRefBm1685772269)(a). The need for representative test runs at the different torque and rotor speed combinations, covering steady states and transient conditions to be encountered in operation, should be evaluated by and agreed with the Agency. [Amdt No: 29/11]