What was found
DURING CRUISE FLIGHT, SELECTED CROSSFEED FROM LEFT TANK TO RIGHT ENGINE. LEFT FUEL BOOST PUMP TURNED ON NORMALLY, FOLLOWED ALMOST IMMEDIATELY BY RIGHT FUEL BOOST PUMP AMBER CAS, THEN LEFT FUEL BOOST PUMP CAS MESSAGE CHANGING TO AMBER. RAN QRH AND CAS MESSAGES DISAPPEARED. DID NOT ATTEMPT ANY FURTHER FUEL CROSSFEED, REST OF FLIGHT UNEVENTFUL. REMOVED & REPLACED THE CHECK VALVE IAW AMM 28-20-30. PERFORMED FUEL CROSS FEED VALVE OPS CHECK IAW AMM. CHAPTER 28-20-00. NO PROBLEM FOUND.