As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE FLIGHT PILOT GOT A WARNING HORN WITH NO WARNING LIGHT. PILOT REDUCED POWER FOR AN AUTOROTATION, FOUND EVERYTHING WORKING NORMALLY AND CANCELLED HORN. 2 MINUTES LATER PILOT NOTICED A DIM HYDRAULIC WARNING LIGHT AND CONDUCTED EMERGENCY PROCEDURE (HYDRAULICS OFF LANDING). INSPECTION BY MAINTENANCE FOUND THE HYDRAULIC PRESSURE SWITCH TO BE FAULTY. SWITCH WAS REPLACED AND OPERATIONALLY CHECKED, AIRCRAFT RETURNED TO SERVICE.