Airworthiness Requirements and Means of Compliance about the Bleed Air Contamination

With the continued growth of aviation transportation, there has been an increase in the events of health and aviation safety related to bleed air contamination, which may degrade the cabin air quality to be threats to the heath of occupants, furthermore, affect the ability of flight crew and cabin crew to perform their duties. Such safety threats are seriously concerned by many civil aviation authorities and have been partially included in the airworthiness regulations. The frequency of such kind of events were investigated after reviewed the data from public literatures comprehensively to estimate the frequency of air supply contamination events involving engine oil or hydraulic fluid and obtained many useful findings. And then current airworthiness standards and the possible further development were summarized and analyzed, including design requirements of transport category airplane and aero-engine. Lastly an analysis model was developed to help showing the compliance of bleed air contamination, and the procedure to apply that model was brought out and demonstrated through an example. Furthermore the numerical tools to determine the retention ratio were constructed and validated partially through the experiments from public literatures. Such numerical models could provide more detailed information of the contaminate transportation process in ECS, which will be helpful for the design of the monitor and filter equipment in the bleed air system.