As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, THE FLIGHT CREW REPORTED THE NUMBER ONE ENGINE LOW OIL PRESSURE LIGHT ILLUMINATED AND OIL QUANTITY WAS SHOWN AT ZERO. THE AIRCRAFT RETURNED TO ITS DEPARTURE AIRPORT. MAINTENANCE FOUND A LOOSE STUD ON THE MAIN OIL FILTER. THE STUD HOLE WAS HELI-COILED IN ACCORDANCE WITH BAC 5064. THE ENGINE WAS SERVICED IN ACCORDANCE WITH THE REQUIREMENTS OF MM 12-13-11. THE ENGINE WAS RUN AND LEAK CHECKED AND FOUND TO BE OPERATING CORRECTLY.