As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
30 MINUTES INTO FLIGHT, HAD AN INDICATION OF A FAILED LEFT WING SPAR VALVE. RETURNED TO DEPARTURE, AND LANDED. AIRCRAFT WAS GROUNDED. MAINTENANCE REPLACED THE SPAR VALVE ACTUATOR IAW 28-27-02 AND PERFORMED SATISFACTORY OPERATIONAL CHECK.