A ventilating and particle-filtering airflow methodology for managing the flow of air to the electrical sliding-contact zone of an on-board aircraft (vehicle) electrical generator. Conduit structure collects intaken air during aircraft (vehicle) engine operation, filters this air to capture and prevent the passage of particles, and directs filtered airflow to that brush region through a close-coupled fluid-flow connection which closes upon and substantially isolates (in terms of incoming airflow) that region. Water drainage is provided for in a region near where filtering takes place. The filtered airflow is substantially the only airflow admitted to this protected region.