Flight Testing an Engine Inlet Barrier Filter for the EC145

The EC145 is a twin engine helicopter with a maximum take-off weight of 3585 kg / 7900 lb. At the request of customers, an Engine Inlet Barrier Filter (EIBF), which consisted of a cotton gauze filter element and a bypass door mechanism, was installed on the helicopter. Flight testing and analysis for development and certification included defining the maximum acceptable level of filter clogging, verification of the inlet airflow distortion and engine response characteristics, performance testing, and substantiating that the EIBF was safe with respect to inadvertent icing. Certification for the EIBF was obtained in the spring of 2008. An evaluation of the EIBF in a sand and desert environment demonstrated the filter's effectiveness and operational capabilities.