Abstract. There is considered a device and the peculiarities in the operation of friction pairs of the fuel systems mentioned. Factors resulting in airing these systems in the course of operation, maintenance and repair of vehicles are emphasized. A wear correlation of a plunger, a plunger tappet, a high-pressure fuel pump casing, and fuel nozzle valves is shown. Main defects of friction pair parts caused by fuel system airing are revealed. There are developed recommendations to avoid airing CRJ fuel system of the fourth generation.

Key words: parts wear, friction pair defects, fuel system, fuel system airing, aircraft.