As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE INSTALLING PITOT/STATIC DRAIN VALVE MODIFICATIONS, FOUND S2 STATIC DRAIN SYSTEM DISABLED. S2 DRAIN VALVE RESERVOIR HAD BLANKING CAP INSTALLED. THE T-FITTING CONNECTING THE LEFT AND RIGHT S2 STATIC SYSTEM WAS CAPPED. THIS LEFT THE S2 SYSTEM WITHOUT A DRAIN. THIS DRAIN IS LOCATED UNDER THE COPILOT SEAT IN AN UNACCESSIBLE AREA DUE TO AVIONICS THAT ARE INSTALLED IN THIS AREA. SUBMITTER STATED THE LOG BOOKS DO NOT REFLECT THIS CHANGE.