As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE DEPARTURE, CLIMBING THROUGH FL240, WHEN THE OIL PRESSURE ON THE LEFT ENGINE STARTED DROPPING. THE MASTER WARNING LIGHT AND THE LOW OIL PRESSURE ANNUNCIATION LIGHT ILLUMINATED, CONFIRMING THE OIL PRESSURE GAUGE INDICATION. THE ENGINE WAS SHUTDOWN . THE CREW FOLLOWED UP WITH THE CHECK LIST AND RETURNED TO DEPARTURE WITHOUT INCIDENT. FOUND THE OIL CAP CRACKED