An engine air filter for heavy dust conditions such as used in heavy military and off-road vehicles, including a scavenging system, and a method of operation thereof. The air filter includes: a housing, a precleaner, a permeable filter, and a scavenger system. The scavenger system disposes of particles collected at the precleaner and on the upstream surface of the permeable filter. The scavenger system includes: an air suction source and a three way valve. The three way valve is airflow coupled to the precleaner, to the permeable filter and to the air suction source. The three way valve enables scavenging of the precleaner and the permeable filter alternately. Optionally, the air filter may further includes a pulse jet back-flow flush system.