What was found
(CAN) NO ACTION FROM THE SERA (SINGLE ENGINE RUDDER ASSISTANCE) DURING TRAINING (PHASE : WATER BOMBING). SERA INDICATION LIGHT ON UPON SELECTION IAW FLIGHT AND OPERATION MANUAL REQUIREMENTS. FLIGHT CREW NOTED: NO ENGAGEMNENT OF SERA SYS. TRAINING ABORTED AND ACFT RETURNED TO BASE. MX PERFORMED TROUBLESHOOTING AND VERFIED FAILED VALVE PN 50347-6, SN 344G. FUNCTION OF THIS VALVE WHEN SELECTED ON IS TO ROUTE HYD PRESSURE TO THE CONCENTRIC SLIDE VALVES. SELECTOR VALVE ALSO ROUTES HYD PRESSURE TO EXTEND THE RUDDER TRIMMER LOCK ACTUATOR.