Optical properties of soot particles emitted by aircraft engines are affected by the chemical composition of the fuel and by the combustion conditions. In this work we investigate the response of certified instruments to soot particles with different physico-chemical properties (chemical composition, organic content, structure, number, etc.). A Combustion Aerosol STandard generator (CAST) designed to burn aeronautic fuel and dedicated to study the emissions after the combustion of Jet A-1 kerosene and synthetic paraffinic kerosene (SPK) is used in atmospheric combustion conditions at three oxidation airflow settings for each fuel. The CAST exhaust is monitored with a multitude of techniques which give information on the physico-chemical properties of particulates and other combustion induced pollutants. Therefore two complementary laser induced incandescence (LII) systems (custom-built and commercial) were used for the evaluation of soot emissions and mass spectrometry was used to study the chemical composition of non-volatile particulate matter (nvPM), semi-volatile particulate matter (svPM) and volatile particulate matter (vPM). A condensation particle counter (CPC) was used to obtain the particle number, a scanning mobility particle sizer (SMPS) was used to measure the particle size distributions and gas detectors were used to monitor the CO/CO2 and SO2 values. The emitted PM was characterized with two mass spectrometry techniques which linked the optical properties of the emissions to their chemical composition function of the experimental configuration and the combustion conditions.