<p>Combustion noise is emerging as a significant contributor to an aircraft’s overall noise signature, making it essential to understand the factors influencing it. This study investigates numerically combustion noise mechanisms in a real helicopter engine. A method combining Large Eddy Simulations (LES), Actuator Disk Theory, and a Helmholtz solver is employed to analyze combustion noise in the combustion chamber, turbine, and far-field, respectively. Two LES databases are compared against experimental data to assess their effects on the predicted noise: (i) the first includes a liquid-fuel injection strategy in the combustion chamber coupled with a realistic first-stage stator downstream, (ii) the second relies on a gaseous-fuel injection in the combustor with a simplified nozzle at the exit. Compared to the gaseous injection, the presence of a liquid spray leads to more pronounced differences in the mechanisms of acoustic generation. Adopting the liquid injection and the stator, combustion noise predictions match more accurately experimental results at the turbine exit and in the far field, displaying a low-frequency resonant peak which is not accounted for in the gaseous case. Direct noise dominates at high frequencies, while indirect entropy noise is more important at low frequencies. The most significant discrepancy between both cases concerns the azimuthal noise distribution at the turbine exit. In the gaseous case, noise is evenly distributed across azimuthal modes, whereas the planar and first azimuthal modes predominantly drive the noise in the liquid injection configuration. This study provides insights into the complex interplay between combustion noise mechanisms, their modes, and the resulting far-field noise.</p>